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Topic: DP Engine Underpowered

Posted By: kidkasha on 11/13/11 10:34pm

Have been looking atMH in the 1999 range, and some of the cummins enginges are at 275 HP. Is this size engine under powered for a 38-40 ft MH? What do you think


Posted By: G Bash on 11/13/11 10:43pm

Had a 275 HP Cummins on a 36 ft. 1999 Georgie Boy, w/one slide. Weight 18,000 LBS. It did fine at that weight. Presently have a 40 ft. with Cat 300 HP, 2 slides at 26,000 LBS. Could use some more HP, I can tell the difference.

Starts up slower and hills need a running start. But you get used to it.

A freind has a 33,000 LBS, 40 footer with 4 slides and a 400 HP Cummins, he does much better and fuel costs are about the same.


2005 Newmar Northern Star DP


Posted By: Mr.Mark on 11/13/11 10:55pm

It's all a matter of weight to HP ratio... We are at 40,000 lbs pulling a 3,400 lb toad with 4 slides and 425 hp. We go slow up steep grades. We are passed by other coaches.

Our Aladdin computer says our average is 8.1 mpg's over 48,500 miles. We are not winning any races but I'm happy with my average fuel economy.

MM


Mr.Mark
2013 Honda CR-V EXL, AWD, w/Nav, SMI Air Force One vacuum-assisted braking
2015 Liberty


Posted By: donsuefuggrwe on 11/13/11 11:18pm

You will not be happy with it.


Posted By: ReverendCharles on 11/13/11 11:58pm

You may want to look at gas units, my 5.3 has 300hp.


Posted By: Executive on 11/14/11 12:05am

My 40' Dynasty had the 300HP Cummins and it really struggled going up large hills, think Grapevine in California. You will not be happy with a 275HP engine, and don't think of pulling anything bigger than a SmartCar with it......My current coach is my recommendation......Dennis


MY SENSE OF HUMOR IS THE MAIN REASON I'LL MOST LIKELY GO TO HELL !
Dennis and Debi Fifth Year Full Timing
Monaco Executive M-45PBQ Quad Slide
525HP Cummins ISM 6 Spd Allison
2014 Chevrolet Equinox LTZ W/ ReadyBrute
CLICK HERE TO VIEW OUR TRAVEL BLOG



Posted By: Golden_HVAC on 11/14/11 12:25am

Hi,
My friend rebuilt his 87 class C with a 460" engine to make about 350 HP, and he leaves his cruise control on while climbing 6% grades at 65 MPH. His buddy with a Fleetwood Egeal does OK until the grades and is slowed to about 45 - he has a 400 HP cat, I think, with a Banks exhaust and other goodies.

Diesel pusher do take the hills a little slower than most gas engine motorhomes, because they are so heavy, and it just takes a couple more minutes to get over them. Really we are not talking about that much time.

My motorhome, at 17,000 pounds, I don't want to push it over the hills, and go up them in second gear at 45 MPH, I am very happy with that speed.

Fred.


Posted By: FormerBoater on 11/14/11 05:14am

If you are looking at 99 year coaches that are 40 footers, you will be happier with the ISC engine.

98 or earlier will have the C8.3 mechanical forerunner of the ISC. We have the 325HP version C8.3 in our Eagle and I have never felt the need for more power even going up Fancy Gap twice in the summertime.

GVWR is 31,000 pounds.

Torque is the big difference with the larger block diesel and that is what helps you get up the hill!


Dave
1998 American Eagle 40EVS


Posted By: DanTheRVMan on 11/14/11 05:16am

Mr.Mark wrote:

It's all a matter of weight to HP ratio... We are at 40,000 lbs pulling a 3,400 lb toad with 4 slides and 425 hp. We go slow up steep grades. We are passed by other coaches.



Calculate the weight to hp ratio for coaches you are interested in.

If you have to be up the hill faster buy a more powerful engine.

If you can deal with going a little slower up hill and would prefer more money in you nest egg do not worry about speed.

But do the calculations for several MHs and make YOUR choice.

BTW, I think the exhaust brake and air ride are the best parts of a DP as they make the journey more pleasant and you should get them regardless of HP.


Dan
Allegro Red 36ft


Posted By: rocmoc on 11/14/11 06:46am

We have a 275hp Cat in a 36 footer HR, 25,000 lbs. With the exception of climbing hills with our HEAVY, Ram pickup, toad attached we do just fine. She slows more with the heavy toad climbing but have never found a hill we could not climb. With a lighter tow load this summer, just under 3,000 lbs of trailer & off-road toys, we climbed 18 long grades in UT & AZ in temps up to 100 degrees. No problems and one of the best trips ever. Of course more power is everyone's desire but how many minutes are spent climbing hills, only a few hours total on a major trip. I get incredible mileage and the money saved in the purchase will pay the fuel for many many miles of RV fun & adventure. If you can get a DEAL it is worth it. A 6 speed Allison Transmission is more important than horsepower IMHO.

rocmoc n AZ


rocmoc n Southern AZ/Mexico



Posted By: rgatijnet1 on 11/14/11 06:56am

Contrary to most of the posts at this forum, not all DP's rocket over hills and not all gas units struggle to make it over a hill. Both get the job done.
If you plan on doing most of your travels in the mountains, get a coach with the most horsepower available, keeping in mind that you will pay the price in fuel economy.
If, you are like most, and occasionally need to climb a long hill, just accept the fact that you will probably be going at the same speed as most truckers in the right hand lane. It is really not that big of a deal whether you have a DP or a gas coach when it comes to steep inclines. Hills are hills and when you go down the other side, they all coast about the same.


Posted By: docj on 11/14/11 07:03am

I hate to re-open an issue that has been discussed many times before, but not all diesel engines with the same rated HP are the same because the torque is different. Torque is almost totally a function of engine size in these diesels and pretty much cannot be changed, but for a given engine size, changes in the ECM can alter the HP output a bit. As a result there are MH's advertised as having 400HP most of which have Cummins ISC engines, some have the Cummins ISL engine, and a few have the ISM. The ISC engine produces ~1050 ft lbs of torque, the ISL is ~1200, and the ISM is ~1500. Guess which one goes up the hill fastest? (Roughly the same is true of the CAT C-7, C-9, and C-12 engines).

We just came back from a summer in WY, MT and ID. Pulling our toad we are ~37,000 pounds with 1550 ft-lbs of torque and "only" 425 HP. Going up hills I hardly ever use the truck lane since we can climb faster than all the trucks and a lot of the smaller cars! LOL


Sandie & Joel

2000 40' Beaver Patriot Thunder Princeton--425 HP/1550 ft-lbs CAT C-12
2014 Honda CR-V AWD EX-L with ReadyBrute tow bar/braking system
WiFiRanger Ambassador/RVParkReviews administrator
Follow our adventures on Facebook at Weiss Travels



Posted By: Mr.Mark on 11/14/11 08:05am

I surely don't plan to win races going up hills. This summer we were going up that long, long (did I say long?)...grade going east in Colorado towards Vail.... WOW, that was one long steep grade!

We climbed that hill at 37 mph and our temperature stayed steady (around 210°). I just put on my flashers and climbed until we reached the top. Two vehicles had overheated, a Prevost tour bus and an 18 wheeler, both off to the side.

MM.


Posted By: jacorso on 11/14/11 08:09am

I have 38' 98 Discovery with a Cummins 275. It's not a super power house or anything but it gets the job done. It is far better than the 454 I had in my 30' coach and I get much better mileage, more than enough to make up the cost difference in fuel.

I think something you need to take in account for the older DP's is that they are not nearly has heavy as the newer ones.


Posted By: John & Angela on 11/14/11 08:14am

It would be enough for me. Hit the right hand lane on the hills, don't be in a hurry and you'll get there about the same time as anyone else.

JMHO


2003 Revolution 40C Class A. 2002 Vanguard 22 foot Class C. Diesel smart car as a Toad on a smart car trailer or pulling a 2009 Timeout Tent Trailer.

Life is not measured by the number of breaths we take but rather by the moments that take our breath away.


Posted By: wolfe10 on 11/14/11 08:19am

First thing is to set REASONABLE EXPECTATIONS. For many, this is their first heavy vehicle. Heavy vehicles ARE different than the cars and SUV's most are used to. Physics DOES apply.

You are not going to climb a 6% grade at 70 MPH in your RV (except maybe Daveinet)-- PERIOD.

Here are some examples from Caterpillar's "Understanding Coach (RV) Performance". The HP are HP at the REAR WHEELS-- makes no difference if the engine is gas, diesel or squirrels on a wheel.

To climb a 6% grade at 55 MPH in a 4,250 pound automobile requires 53 HP at the rear wheels. NO PROBLEM.

A coach/toad with GCW of 34,000 pounds requires 402 HP, AGAIN AT THE REAR WHEELS. One would have to look long and hard to find a 500+ HP (to generate 402 HP at the rear wheels) in an under 30,000 pound coach (coach + toad= 34,000 pounds). And for a larger coach, say 52,500 pounds GCW, it would require 587 HP at the rear wheels to climb at 55 MPH.

A reasonable expectation is that you will climb faster than a loaded 18 wheeler and slower than an empty one-- based on power to weight ratio.


Brett Wolfe
2003 Alpine 38'


FMCA Forum: www.community.fmca.com/index

Diesel RV Club:http://www.dieselrvclub.org/


Posted By: DanTheRVMan on 11/14/11 09:11am

The OP really should have posted the weight not length of the MH.

But another rule of thumb people use is 1 hp for every hundred pounds. So if the mh and toad weigh less than 27,500 you will be similar to most MH out there.

If it is more than 27,500 pounds and the coach is rated for your toad and you have some good music and like to sing then you may enjoy the slower journey up the hill than many people who will not be satisfied unless they are passing everybody.

I would not let a few extra minutes going up a hill ruin a weeks or even a weekends camping trip.


Posted By: wny_pat on 11/14/11 10:06am

My Cummins B5.9, 230 H.P., 605 Ft. Lb @ 1600 RPM, engine pulling 24000 lbs goes up slowly, but I've been going up hill slowly much of my truck driving life so I don't mind it. Gives me more time to safely look around and much better fuel mileage than I would expect out of a bigger engine that could go up hill much faster. A Cummins ISX 650 hp would probably get me in trouble with the cops! 1950 lb-ft of torque!!! Just think of the damage that could do to a drive train!


“All journeys have secret destinations of which the traveler is unaware.”


Posted By: MartinDYN on 11/14/11 10:11am

The old race car formula still applies.

MPH is from HP which costs $$$. How fast can you afford to go?


'70 Jeep CJ5 + Sears Tent(Sold)
'70 Jeep + '63 Field and Stream Trailer(Sold)
'86 Ford F250 + Lance Camper(Sold)
'73 Dodge Sportscoach Class A(Sold)
'86 GM Eleganza 31' Class A(Sold)
'99 Suburban + '74 AS Landyacht(Sold)
'97 Damon Intruder 35' DP CAT


Posted By: Cloud Dancer on 11/14/11 10:23am

My wife sez, a putz is an old man who rides around in an old Cushman scooter that goes, putt-putt, putt-putt.....
I don't want to be called an ole putz, therefore I ordered my DP with the 1050 lb torque 8.3 engine. At 32,000 lbs of gross weight, I certainly would not want an engine with less torque.


Willie & Betty Sue
Miko & Sparky
2003 41 ft Dutch Star Diesel Pusher/Spartan
Floorplan 4010
Blazer toad & Ranger bassboat


Posted By: RVGRINGO on 11/14/11 10:27am

Ours was a '99 Holiday Rambler Endeavor with 270 HP Cummins and we had no complaints at all. We travelled both the Canadian and American Rocky Mountains without difficulty. Go for it!


Posted By: vacuumbed on 11/14/11 06:17pm

What do ya guys think of the 400 horse Cummins M11?


Posted By: Jarlaxle on 11/14/11 11:19am

At this point, I would prefer a 5.9 Cummins in just about any coach short of a 40,000+ lb 40' rig. It is the mileage champ, it is perfectly happy to haul around 30,000+lbs for years. If pulling a grade means running with the pedal planted & the engine wound out to 3000rpm on the governor...then so be it, wont hurt anything.


John and Elizabeth (Liz), with 3 nutty cats
My beloved St. Bernard, Marm, lost him 1/2/12
Current rig:
1992 International Genesis school bus conversion


Posted By: litespeed on 11/14/11 05:10pm

The poster who recommended a 5.3 Gas rig must have been joking. Towing capacity is based on the shape of the torque and hp curves. High horsepower, small displacement gas motors work great in light cars but cannot pull a load.The only way a 5.3 would pull any real weight would be to gear it to turn 4500 rpm almost all the time. And then you would have very short engine life, terrible gas mileage....and etc...


Jay & Lee(and Lucy..the Jack Russell Terrorist)
2010 Dutch Star 4010 DP with 2011 Jeep Rubicon in tow


Posted By: slemnah on 11/14/11 05:19pm

I have a 1997 HR Imperial 40WDS with a C8.3 Cummins with a Banks Turbo Kit. I won't ever win any drag races or pulling contests but it will climb the Grapevine with a Ford Edge behind it at around 35mph. Just make sure to keep the revs around 2,000 and don't get caught behind a slow truck and you will be fine.


Posted By: bbattey on 11/14/11 06:15pm

You really can't compare diesel to gas engines by comparing HP numbers. HP is just a calculation from torque and rpm, & it's torque that twists the axles & gets you up the hills. The formula is: HP = (Torque x rpm) / 5252. (Notice that torque is always = HP at 5252 RPM.)

The 2005-up Ford v10, for example, makes 362 HP at 4750 rpm and 457 ft-lb at 3250 rpm. The 275 HP Cummins diesel has almost 100 fewer HP, but it makes that 275 HP at something like 2000 rpm, which, by the formula above, means its maximum torque = 722 ft-lb, way more than the V10.

Dividing coach weight by maximum engine torque is a good way to compare hill climbing ability between coaches. The smaller the number, the faster it'll go up the hill.


Holiday Rambler Imperial 34 ft 454 TBI P30 chassis Smart Fortwo toad



Posted By: michahicks on 11/14/11 06:19pm

wolfe10 wrote:


A reasonable expectation is that you will climb faster than a loaded 18 wheeler and slower than an empty one.


This is exactly what I've experienced. '97 37' HR Endeavor, 275hp Cat, just under 30,000 with toad. Put it on the mat and let Mr. Allison do the thinking. Not a problem at all. The top of the hill will come soon enough - then it's your turn to start thinking!

Watch how the trucks handle the hills when you get into them. There are some lessons that can be learned pretty easily.


1997 38' HR Endeavor, 275 Cat, Freightliner
2003 CR-V Toad, Blue Ox, Ready Brake


Posted By: wolfe10 on 11/14/11 08:19pm

vacuumbed wrote:

What do ya guys think of the 400 horse Cummins M11?


In what weight coach??? Or more exactly what GCW? Could be a hotrod or a dog.


Posted By: vacuumbed on 11/14/11 08:30pm

wolfe10 wrote:

vacuumbed wrote:

What do ya guys think of the 400 horse Cummins M11?


In what weight coach??? Or more exactly what GCW? Could be a hotrod or a dog.

96 Monaco Executive 40'. No slide. GVW 35,000. Hope this helps.


Posted By: wolfe10 on 11/14/11 08:36pm

vacuumbed wrote:

wolfe10 wrote:

vacuumbed wrote:

What do ya guys think of the 400 horse Cummins M11?


In what weight coach??? Or more exactly what GCW? Could be a hotrod or a dog.

96 Monaco Executive 40'. No slide. GVW 35,000. Hope this helps.


You would be in the "climb faster" club.

A good motor, but at that age, maintenance history is important. As an example, this is a linered engines, so if coolant has been neglected it could be very expensive. If coolant has been maintained (SCA level maintained or an OAT-based coolant used) that would be a non-issue.


Posted By: DSDP Don on 11/14/11 10:12pm

kidkasha.......Keep in mind that steep grades are usually only about 5% of your travel. On a five mile grade, you're only looking at about an additional five minutes to climb the grade versus a high horsepower/torque coach.

Remember.......gas engines accelerate, diesel engines gain momentum.


Don & Mary
2014 Newmar Dutch Star 4018
450 Cummins
2012 Chevrolet Silverado LTZ CrewCab 4WD
2013 Polaris RZR 800 LE



Posted By: DanTheRVMan on 11/14/11 10:41pm

HP determines speed up hill

Torgue is a static number that simply measures the angular force in foot-pounds

HP is foot-pounds delivered per second.

1 hp = 550 foot-pounds per second

One engine can have higher torque than another engine and deliver that torque less quickly than another engine.

IF you can not comprehend the difference think of water flowing from a pipe. Which is better 50 psi or 100 psi for delivering water? What if the 100 psi is a 1 inch diameter pipe and the 50 psi is a 10 inch diameter pipe? Torque (like psi) by it self tells you nothing about how fast something will go and this is why people measure horse power.


Posted By: vacuumbed on 11/15/11 01:49am

Thanks for the info wolfe10

This thread reminds me of a decal I once saw on a CAT powered Safari Continental. It read...

"If it's not a CAT, it's a DOG"


Posted By: JetAonly on 11/15/11 04:32pm

Driving a turbo charged diesel at 10000 ft, think Vail Pass or Eisenhower Tunnel, is different. The Allison doesn't mind engine temperatures. There is a lot of physics going on that is not visible. At 5000 ft there is approximately a 30% reduction in atmospheric pressure, so the turbo charger has a lot of catching up to do. The engine is cool by the mass of air flow not the volume. FWIW


2000 Monaco Dynasty
ISC350


Posted By: 03FatBoy on 11/15/11 05:34pm

Executive wrote:

My 40' Dynasty had the 300HP Cummins and it really struggled going up large hills, think Grapevine in California. You will not be happy with a 275HP engine, and don't think of pulling anything bigger than a SmartCar with it......My current coach is my recommendation......Dennis


We would probably all love to have 525 hp, but most of us can't afford.
Our 330 in our Ambassador passes most going up hill.


Melissa & Steve (MNC USNR retired)
FMCA F335327, GS
'05 HR Ambassador 36PDD, Saturn Vue Toad
8.3L Cummins w/ 6sp Allison


Posted By: bbattey on 11/15/11 04:45pm

@DanTheRVMan- I know, HP seems like the better measurement, since it's a unit of power, which is the time rate of doing work. For example, say you have to push a big box 10 feet across the room, & it takes 55 lb force to push it. If you manage to push the box 10 ft in one second, you've generated (55 lb x 10 ft)/1 second = 550 ft-lb/sec, which is 1 HP. (You are VERY strong!) If you take 10 seconds to push the box 10 ft, you've only generated 55 ft-lb/sec, which is 0.1 HP. (You're a mortal!)

The trouble is, the time unit chosen for rotating engines is RPM, which isn't analogous to the time to push the box across the room (or the time to get the coach up the hill).

I've been thinking more about comparing the hill climbing ability of gas to diesel coaches & have concluded that it's more complicated than just dividing weight by torque.

Gas engined motorhomes go up grades at about the same speed as diesels, but at twice the rpm, which doubles the torque delivered to the drive axles.

You can compare gas coach hill climbing ability by dividing coach weight by HP; the coach with the lower number will probably climb the fastest. You can use HP because most gas coaches climb hills at about the same RPM (4000 or so), so the RPM cancels out in the comparison.

You can use the same calculation to compare diesel coaches, weight divided by HP. This is because diesel coaches also climb hills at about the same RPM (2000 or so).

Simplifying a little, the actual calculation to determine the twisting force that the engine is applying to the drive wheels at each rpm is (engine torque at that rpm) x (transmission gear ratio) x (rear axle gear ratio) / (drive tire diameter).

Examples, gas vs diesel (assume both coaches weigh the same) going up a long grade at full throttle:

1) 275 HP diesel at 45 mph and (typically) 2000 rpm.

Let's say the transmission gear ratio going up the hill is 2:1 and the rear axle gear ratio is 2.5:1. The engine is generating 722 ft-lb torque at 2000 rpm. The engine, transmission and differential is delivering:

722 x 2 x 2.5 = 3610 ft-lb

to the drive axles.

2) 362 HP gasser at 45 mph = 4000 rpm.

Engine is generating about 425 ft-lb torque at 4000 rpm.

Notice, though, that the gasser's rpm is twice that of the diesel at the same mph, so its gear ratios must be twice that of the diesel:

424 x 2 x 2.5 x 2 = 4240 ft-lb

to the drive axles

So, in this simplified example, the gasser has about 17% more oomph to push it up a grade at 45 mph. The gasser could go up a steeper grade than the diesel and still go 45 mph.

The 17% greater torque the gasser has in this example, however, is considerably less than the roughly 32% more rated HP that the gasser has. Using HP to compare diesel vs gas would introduce a lot of error. So would using just torque.

So, here's my quick & dirty gas vs diesel hill climbing ability determiner:

Diesel: weight divided by (rated HP x 2.5)

Gasser: weight divided by (HP + torque)

Lowest number wins

My thinking is:

- Multiplying diesel HP by 2.5 gets us close to the diesel's torque at about 2000 rpm, since torque & HP are always equal at 5252 RPM. (2000 x 2.5 = 5000)

- Averaging the gasser's HP & torque (HP + torque divided by 2) gets us close to its torque at 4000 rpm, but it has a 2x gear advantage, which leaves us with just HP + torque.

For the above coaches if they both weigh 20,000 lb:

Diesel: 20,000 / (275*2.5) = 29

Gasser: 20,000 / (362 + 457) = 24.4

The gasser, with the lower number, wins.

I've spent way too much time on this, but I (obviously) love this stuff.


Posted By: DanTheRVMan on 11/15/11 05:37pm

bbattey

You may love this stuff, but you desperately need a physics course.

I remember Dr. Resnick saying many students viewed the equations as a hot dog meat grinder. You put the meat at the top turn the crank and out came the hot dogs. Analogously, physics student did not understand physics and the equations and just plugged numbers into equations trying to get a result.

If you do not know who Dr. Resnick is look up Halliday and Resnick who I assume are deceased as the current premier physics book used by engineering colleges has some new guy (Krane - probably pretty smart) as an author.

We use RPM with torque because it is angular force so we have to use angular measurements like rpm. Your stating it is inappropriate for going up hill shows a lack of understanding.

A force or a torque is just that a singular unit with no concept of how fast anything happens. HP and velocity are measures of speed. Units per second. Max torque (ft-lb) which you respect has nothing to due with ft-lb per second.

Let me try another analogy with you. Max tensile strength on some glasses is higher than max tensile strength on many high strength steels. But which is tougher. If you were tied to the side of a cliff would you want to be tied by a piece of glass with 5 times the tensile strength of steel or steel. Ok not the best analogy but do you understand you can not look at a single factor?

The max torque say nothing about how many ft-lbs are available per minute or delivered per minute or second. They are different ways at looking at the engine. The engine is not defined by one number. Not torque. Not liters. Not number of cylinders. Not RPM. Not number of valves. Not horsepower. not any single number.

1 hp is 550 ft-lb per second. The more ft-lbs delivered per second will make it go faster. This is the unit most appropriate to determine power and therefore speed.

Unfortunately uninformed diesel mechanics and uninformed salesman have confused people for years.

Another consideration is if I did not care about going down the road and simply built the transmission to deliver max torque at the wheels do you realize i could design a transmission that delivered more torque at the wheels for a 10 hp engine than is delivered by a 500 hp engine with a traditionally designed transmission. YES absolutely a 10 hp engine with a ridiculously silly designed transmission could deliver higher torque than a 500 hp off the shelf system. BUT it would be slow as molasses and much more interesting watching paint dry.

Sorry if I went long but the lack of understanding concerning torque - which is a good thing and HP - which is a good thing is amazing to me even to people with engineering degrees so do not feel so bad if your having trouble.

* This post was edited 11/15/11 05:50pm by DanTheRVMan *


Posted By: bukib on 11/15/11 07:56pm

beautifully crafted posts to be sure. it still begs the question...what is your hurry? when i want to go fast i take out my corvette. but when i want a relaxed, no pressure trip i pull out the airstream. i dont need to pass anybody. i lay back and let it purr. so i only hit 45 going up. its coming down that becomes terrifying.Last winter we left dandridge tn on the cumberland plateau the grade was unreal. i never let on to my family that i was hanging on for dear life. just go with what you got. the 0nly difference in a 190 and a 500 is how white you want your knuckles to get.


Posted By: kidkasha on 11/15/11 08:29pm

My friend Billy told mr that he got a ticket on 6% grade for speeding and breaking trction w/ a 275 HP Cummis in a 40ft LoveBoat


Posted By: bbattey on 11/15/11 09:27pm

@DantheRVman- I didn't mean to insult you in any way with my post. From your response, it kinda looks like you took it that way. I certainly intend no malice & will not deliver any.

"We use RPM with torque because it is angular force." Will you please explain to me what 'revolutions per minute' has to do with force? I don't see any relation.

Torque, on the other hand, is a measure of the force required to rotate something about an axis. The SAE units of measurement is ft-lbs. That's a distance (feet) times a force (pounds).

"Your stating it is inappropriate for going up hill shows a lack of understanding."

I never said that. Of course rpm is appropriate for going uphill! The gasser's higher rpm ability is what allows it to overcome its lower torque output compared to the diesel; it can deliver its torque through a higher gear ratio, thus delivering more torque to the drive axles. (See the example in my previous post, where the gasser has a 2X gear ratio advantage, allowing the coach to have more torque at the drive axles even though the gas engine's max torque is 457 ft-lb compared to the diesel's 722 or so.)

"HP and velocity are measures of speed."

I don't see how how HP (ft-lb/second) is a measure of speed. Speed is distance traveled per unit time, as in miles/hour. Maybe you mean that HP is the time rate of doing work & speed is the time rate of traveling a distance, but that's not the same thing as saying that HP is not a measure of speed. (Velocity isn't a measure of speed either; it's speed in a direction, if you remember what Halliday & Resnick taught us.)

"The engine is not defined by one number."

I certainly agree with that! I'm not talking about a single factor like an engine's max torque, I'm talking about an engine's torque curve; the torque it can produce at each rpm. The curve is determined by putting the engine on a dynamometer & measuring the torque (twisting force) it can produce at 500 or so rpm increments over the engine's operating range. The measurements are then plotted on a graph with torque usually on the vertical scale & rpm on the horizontal scale. The line formed by connecting the data points is usually a concave down shaped curve; the highest point of the curve is the engine's maximum torque. (Did you know that dynamometers measure nothing but torque, and that the HP curve is generated by applying the conversion formula to the torque curve?)

"The more ft-lbs delivered per second will make it go faster."

Yup, I agree with that too. An engine that generates more HP at any RPM will also generate more torque at that RPM. I wasn't saying that HP isn't important; I was saying that you can't directly compare diesel HP ratings to gas engine HP ratings because they generate their rated HPs at very different RPMs. That was the main point of my post.

Think about this: In order for the coach to go up a hill, its drive tires need to exert a force on the road that is parallel to the road. In order for the tires to exert that force, the axles attached to the drive wheels need to twist the wheels. In order for that to happen, something needs to twist (apply a torque to) the drive axles. In this case, the ring gear in the rear axle's differential applies the torque. then it's all gears & rotating shafts through the differential & transmission until it gets to the cranksahft in the engine, which is the thing applying the torque to the whole shebang.

The forces required to push a coach up a hill at a given speed are the rolling & aerodynamic drag forces plus the force required to lift the coach up the grade. I know of no way to calculate how fast that coach could go up that hill without knowing how much twisting force the engine can produce. I can calculate it if I know the engine's HP curve, but first I'd have to use the infamous formula to get the torque curve.

I stand by everything I said. My gas vs diesel hill climbing ability comparator is probable not accurate in all cases, but I was looking for something that a non-Physics lover could use to get a first rough estimate using readily available informantion.

Ain't Physics fun?


Posted By: Executive on 11/15/11 10:19pm

bbattey wrote:

@DantheRVman- I didn't mean to insult you in any way with my post. From your response, it kinda looks like you took it that way. I certainly intend no malice & will not deliver any.

"We use RPM with torque because it is angular force." Will you please explain to me what 'revolutions per minute' has to do with force? I don't see any relation.

Torque, on the other hand, is a measure of the force required to rotate something about an axis. The SAE units of measurement is ft-lbs. That's a distance (feet) times a force (pounds).

"Your stating it is inappropriate for going up hill shows a lack of understanding."

I never said that. Of course rpm is appropriate for going uphill! The gasser's higher rpm ability is what allows it to overcome its lower torque output compared to the diesel; it can deliver its torque through a higher gear ratio, thus delivering more torque to the drive axles. (See the example in my previous post, where the gasser has a 2X gear ratio advantage, allowing the coach to have more torque at the drive axles even though the gas engine's max torque is 457 ft-lb compared to the diesel's 722 or so.)

"HP and velocity are measures of speed."

I don't see how how HP (ft-lb/second) is a measure of speed. Speed is distance traveled per unit time, as in miles/hour. Maybe you mean that HP is the time rate of doing work & speed is the time rate of traveling a distance, but that's not the same thing as saying that HP is not a measure of speed. (Velocity isn't a measure of speed either; it's speed in a direction, if you remember what Halliday & Resnick taught us.)

"The engine is not defined by one number."

I certainly agree with that! I'm not talking about a single factor like an engine's max torque, I'm talking about an engine's torque curve; the torque it can produce at each rpm. The curve is determined by putting the engine on a dynamometer & measuring the torque (twisting force) it can produce at 500 or so rpm increments over the engine's operating range. The measurements are then plotted on a graph with torque usually on the vertical scale & rpm on the horizontal scale. The line formed by connecting the data points is usually a concave down shaped curve; the highest point of the curve is the engine's maximum torque. (Did you know that dynamometers measure nothing but torque, and that the HP curve is generated by applying the conversion formula to the torque curve?)

"The more ft-lbs delivered per second will make it go faster."

Yup, I agree with that too. An engine that generates more HP at any RPM will also generate more torque at that RPM. I wasn't saying that HP isn't important; I was saying that you can't directly compare diesel HP ratings to gas engine HP ratings because they generate their rated HPs at very different RPMs. That was the main point of my post.

Think about this: In order for the coach to go up a hill, its drive tires need to exert a force on the road that is parallel to the road. In order for the tires to exert that force, the axles attached to the drive wheels need to twist the wheels. In order for that to happen, something needs to twist (apply a torque to) the drive axles. In this case, the ring gear in the rear axle's differential applies the torque. then it's all gears & rotating shafts through the differential & transmission until it gets to the cranksahft in the engine, which is the thing applying the torque to the whole shebang.

The forces required to push a coach up a hill at a given speed are the rolling & aerodynamic drag forces plus the force required to lift the coach up the grade. I know of no way to calculate how fast that coach could go up that hill without knowing how much twisting force the engine can produce. I can calculate it if I know the engine's HP curve, but first I'd have to use the infamous formula to get the torque curve.

I stand by everything I said. My gas vs diesel hill climbing ability comparator is probable not accurate in all cases, but I was looking for something that a non-Physics lover could use to get a first rough estimate using readily available informantion.

Ain't Physics fun?


Reading all this makes my eyeballs bleed.........Dennis


Posted By: Mr.Mark on 11/15/11 10:26pm

Executive wrote:

bbattey wrote:

@DantheRVman- I didn't mean to insult you in any way with my post. From your response, it kinda looks like you took it that way. I certainly intend no malice & will not deliver any.

"We use RPM with torque because it is angular force." Will you please explain to me what 'revolutions per minute' has to do with force? I don't see any relation.

Torque, on the other hand, is a measure of the force required to rotate something about an axis. The SAE units of measurement is ft-lbs. That's a distance (feet) times a force (pounds).

"Your stating it is inappropriate for going up hill shows a lack of understanding."

I never said that. Of course rpm is appropriate for going uphill! The gasser's higher rpm ability is what allows it to overcome its lower torque output compared to the diesel; it can deliver its torque through a higher gear ratio, thus delivering more torque to the drive axles. (See the example in my previous post, where the gasser has a 2X gear ratio advantage, allowing the coach to have more torque at the drive axles even though the gas engine's max torque is 457 ft-lb compared to the diesel's 722 or so.)

"HP and velocity are measures of speed."

I don't see how how HP (ft-lb/second) is a measure of speed. Speed is distance traveled per unit time, as in miles/hour. Maybe you mean that HP is the time rate of doing work & speed is the time rate of traveling a distance, but that's not the same thing as saying that HP is not a measure of speed. (Velocity isn't a measure of speed either; it's speed in a direction, if you remember what Halliday & Resnick taught us.)

"The engine is not defined by one number."

I certainly agree with that! I'm not talking about a single factor like an engine's max torque, I'm talking about an engine's torque curve; the torque it can produce at each rpm. The curve is determined by putting the engine on a dynamometer & measuring the torque (twisting force) it can produce at 500 or so rpm increments over the engine's operating range. The measurements are then plotted on a graph with torque usually on the vertical scale & rpm on the horizontal scale. The line formed by connecting the data points is usually a concave down shaped curve; the highest point of the curve is the engine's maximum torque. (Did you know that dynamometers measure nothing but torque, and that the HP curve is generated by applying the conversion formula to the torque curve?)

"The more ft-lbs delivered per second will make it go faster."

Yup, I agree with that too. An engine that generates more HP at any RPM will also generate more torque at that RPM. I wasn't saying that HP isn't important; I was saying that you can't directly compare diesel HP ratings to gas engine HP ratings because they generate their rated HPs at very different RPMs. That was the main point of my post.

Think about this: In order for the coach to go up a hill, its drive tires need to exert a force on the road that is parallel to the road. In order for the tires to exert that force, the axles attached to the drive wheels need to twist the wheels. In order for that to happen, something needs to twist (apply a torque to) the drive axles. In this case, the ring gear in the rear axle's differential applies the torque. then it's all gears & rotating shafts through the differential & transmission until it gets to the cranksahft in the engine, which is the thing applying the torque to the whole shebang.

The forces required to push a coach up a hill at a given speed are the rolling & aerodynamic drag forces plus the force required to lift the coach up the grade. I know of no way to calculate how fast that coach could go up that hill without knowing how much twisting force the engine can produce. I can calculate it if I know the engine's HP curve, but first I'd have to use the infamous formula to get the torque curve.

I stand by everything I said. My gas vs diesel hill climbing ability comparator is probable not accurate in all cases, but I was looking for something that a non-Physics lover could use to get a first rough estimate using readily available informantion.

Ain't Physics fun?


Reading all this makes my eyeballs bleed.........Dennis


Dito.


Posted By: wny_pat on 11/15/11 11:07pm

Don't know anything about Halliday & Resnick, but I do know how, back in the early 1970s, a 425 Cat will pull Hamilton Hill, Hamilton, Ontario, pulling 135,000 lbs and walk away from most other brand diesels of comparable size pulling the same load, on the same hill. But I also know that Cats do break down and it is a well know fact that Cummins will almost always get you home. And those diesels on the same hill will run away from a loaded 534 Ford (277 HP and 490 ft lbs @ 1800/2300 rpm) which was popular with the company owned car haulers of that era. I wonder if either Halliday or Resnick could drive a Pete with a 425 Cat and Roadranger 13 speed, pulling that kind of weight up that hill without dropping the driveshaft?


Posted By: DanTheRVMan on 11/16/11 02:04am

bbattey wrote:

@DantheRVman- I didn't mean to insult you in any way with my post. From your response, it kinda looks like you took it that way. I certainly intend no malice & will not deliver any.

Not an insult, text is just a difficult way to communicate (especially for an engineer

"We use RPM with torque because it is angular force." Will you please explain to me what 'revolutions per minute' has to do with force? I don't see any relation.

Torque is a moment like turning a bolt so we would naturally use rpm for something that rotates

Torque, on the other hand, is a measure of the force required to rotate something about an axis. The SAE units of measurement is ft-lbs. That's a distance (feet) times a force (pounds).

"Your stating it is inappropriate for going up hill shows a lack of understanding."

I never said that. Of course rpm is appropriate for going uphill! The gasser's higher rpm ability is what allows it to overcome its lower torque output compared to the diesel; it can deliver its torque through a higher gear ratio, thus delivering more torque to the drive axles. (See the example in my previous post, where the gasser has a 2X gear ratio advantage, allowing the coach to have more torque at the drive axles even though the gas engine's max torque is 457 ft-lb compared to the diesel's 722 or so.)

"HP and velocity are measures of speed."

I don't see how how HP (ft-lb/second) is a measure of speed. Speed is distance traveled per unit time, as in miles/hour. Maybe you mean that HP is the time rate of doing work & speed is the time rate of traveling a distance, but that's not the same thing as saying that HP is not a measure of speed. (Velocity isn't a measure of speed either; it's speed in a direction, if you remember what Halliday & Resnick taught us.)

Yes poorly worded on my part. (responding during happy hour was foolish velocity can be measured in ft/sec. HP is measured in ft-lb/sec. One is a measure of distance per second and the other is a measure of ft-lb delivered per second. Get the connection? HP is how fast you are delivering the ft-lb to get your MH to move. Torque on the other hand is a static measurement.

Yes I also understand the difference between a unitary number like speed and a vector like velocity, but now your just nitpicking for no good reason and likely confusing others. It is quite common to colloquially interchange the two during engineering discussions.


"The engine is not defined by one number."

I certainly agree with that! I'm not talking about a single factor like an engine's max torque, I'm talking about an engine's torque curve; the torque it can produce at each rpm. The curve is determined by putting the engine on a dynamometer & measuring the torque (twisting force) it can produce at 500 or so rpm increments over the engine's operating range. The measurements are then plotted on a graph with torque usually on the vertical scale & rpm on the horizontal scale. The line formed by connecting the data points is usually a concave down shaped curve; the highest point of the curve is the engine's maximum torque. (Did you know that dynamometers measure nothing but torque, and that the HP curve is generated by applying the conversion formula to the torque curve?)

"The more ft-lbs delivered per second will make it go faster."

Yup, I agree with that too. An engine that generates more HP at any RPM will also generate more torque at that RPM. I wasn't saying that HP isn't important; I was saying that you can't directly compare diesel HP ratings to gas engine HP ratings because they generate their rated HPs at very different RPMs. That was the main point of my post.

HP is HP. It really does not matter if it is gas, diesel, or squirrels in a cage delivering the HP. (OK I stole the squirrels comment from some one in this thread or another thread, but the guy had a good point

Think about this: In order for the coach to go up a hill, its drive tires need to exert a force on the road that is parallel to the road. In order for the tires to exert that force, the axles attached to the drive wheels need to twist the wheels. In order for that to happen, something needs to twist (apply a torque to) the drive axles. In this case, the ring gear in the rear axle's differential applies the torque. then it's all gears & rotating shafts through the differential & transmission until it gets to the cranksahft in the engine, which is the thing applying the torque to the whole shebang.

Yes, but again force or torque by itself will not get you to speed they are static (no motion) measures.

The forces required to push a coach up a hill at a given speed are the rolling & aerodynamic drag forces plus the force required to lift the coach up the grade. I know of no way to calculate how fast that coach could go up that hill without knowing how much twisting force the engine can produce. I can calculate it if I know the engine's HP curve, but first I'd have to use the infamous formula to get the torque curve.

I stand by everything I said. My gas vs diesel hill climbing ability comparator is probable not accurate in all cases, but I was looking for something that a non-Physics lover could use to get a first rough estimate using readily available informantion.

you made up your own formulas to approximate things with no basis for them.

In physics, power is the RATE at which energy is transferred, used, or transformed. It is the rate or how fast the energy is transferred that will determine the rate at which the MH moves.


Ain't Physics fun?


* This post was edited 11/16/11 02:14am by DanTheRVMan *


Posted By: JetAonly on 11/16/11 05:22am

Yikes!

The main reason a modern diesel pulls hills better is because it doesn't lose power with altitude.

Think of it this way, Torque tells you how much you can pull, HP tells you how fast you can pull it.


Posted By: rgatijnet1 on 11/16/11 05:39am

JetAonly wrote:

Yikes!

The main reason a modern diesel pulls hills better is because it doesn't lose power with altitude.

Think of it this way, Torque tells you how much you can pull, HP tells you how fast you can pull it.


And all of that only matters if you have a transmission that automatically shifts, or that you can manually shift, to the proper gear to take advantage of the engines HP and torque curve. If not, the engines max HP and Max torque is irrelevant.


Posted By: DanTheRVMan on 11/16/11 06:38am

JetAonly wrote:

Yikes!

The main reason a modern diesel pulls hills better is because it doesn't lose power with altitude.

Think of it this way, Torque tells you how much you can pull, HP tells you how fast you can pull it.


yes the elevation will affect the hp of the gas engine out west (probably the squirrels as well

Then you need to consider the down rated hp of the gas engine at whatever elevation is appropriate. But my main point is you need to compare hp because:

In physics, power is the RATE at which energy is transferred, used, or transformed. It is the rate or how fast the energy is transferred that will determine the rate at which the MH moves.


Posted By: Cloud Dancer on 11/16/11 07:49am

DanTheRVMan wrote:

HP determines speed up hill

Torgue is a static number that simply measures the angular force in foot-pounds

HP is foot-pounds delivered per second.

1 hp = 550 foot-pounds per second

One engine can have higher torque than another engine and deliver that torque less quickly than another engine.

IF you can not comprehend the difference think of water flowing from a pipe. Which is better 50 psi or 100 psi for delivering water? What if the 100 psi is a 1 inch diameter pipe and the 50 psi is a 10 inch diameter pipe? Torque (like psi) by it self tells you nothing about how fast something will go and this is why people measure horse power.



One difference between you and me is that you seem to respond as if you're teaching from a textbook. The way you put it really isn't the way it is in the world of selecting which engine to order, for your diesel pusher. First of all the torque that is represented by the torque/HP graph which is published by the engine manufacturer is IMO not "static". The torque on this type of graph is occurring at a certain engine RPM. Whereas, a "static torque" is better described by the ole one-pound rock dangling from the end of a one-foot stick.
Sure, you can argue this all day long, but will it do any good to do so here?
I wish you guys would simply talk about comparing torque/HP graphs between the different size, and types, of engines. And, then explain how all this relates to the actual performance of the AVAILABLE motorhomes.
Otherwise IMO a more practical piece of information is simply the GVWR-to-peak torque ratio. At this stage of competition, it's a safe bet that the chassis manufacturer has selected suitable gear ratios.
I know this was true back when I was doing the research. It worked for me, as I never found any reason why I would want to change any of the gear ratios on my transmission and differential (for normal RVing). Now, if I wanted to "chip" my engine to 400 HP, and also change a gear ratio, then I'd be wanting to be into a different thread.


Posted By: wolfe10 on 11/16/11 08:15am

I am a little hesitant to get into this HP/torque discussion, but here goes anyway.

There are high torque/low RPM engines-- diesels.

There are medium torque/medium RPM engines-- gasoline.

There are very low torque/very high RPM engines-- turbine/jet.

The same HP produced by each will push the same coach up the same grade at the same speed.

The difference is that the diesel engine can do that at an RPM that is can safely sustain for hours at a time. Not so the HP of a gasoline engine-- its peak HP is at too high an RPM to safely run for extended periods of time.

But, though I own and like a diesel, I would be the first to say that I could have driven a gasoline powered coach 100% of the places I have driven our diesel. Yes, a little slower and using more fuel, but at lower initial cost.


Posted By: DanTheRVMan on 11/16/11 08:27am

cloud dancer

A lot of people do not under stand so yes that needs correcting.

The curve is more informative than the single reported number, but on a long hill in real life between your foot on the accelerator and down shifting as needed your going to get near that max hp number relatively quickly.

In real life this problem typically comes up when comparing two engines like the isb engine 360hp and 660 ft-lb torque and the isc engine 380 hp and 1050 ft-lb torque. The torque is dramatically different between the two engines while the hp is essentially the same.

It is HP and the rate or how fast the energy is transferred that will determine the rate at which the MH moves. The difference between the above two engines hp is negligible. In real life they will be essentially the same speed (assuming similar weight MHs)

The two curves are a secondary or tertiary factor. In real life both drivers will get to essentially the same hp and essentially the same rate of energy transfer at approximately the same time. They will then settle in for the long haul up the hill at essentially the same speed.

Comparing the two torques for hill climbing is misleading and shows a lack of understanding about the speed at which a mh climbs a big hill.

If you want to go fast get a 500 or 600 hp engine not an engine with 20 more hp or drive a corvette


Posted By: Cloud Dancer on 11/16/11 08:45am

DanTheRVMan wrote:

cloud dancer

A lot of people do not under stand so yes that needs correcting.

The curve is more informative than the single reported number, but on a long hill in real life between your foot on the accelerator and down shifting as needed your going to get near that max hp number relatively quickly.

In real life this problem typically comes up when comparing two engines like the isb engine 360hp and 660 ft-lb torque and the isc engine 380 hp and 1050 ft-lb torque. The torque is dramatically different between the two engines while the hp is essentially the same.

It is HP and the rate or how fast the energy is transferred that will determine the rate at which the MH moves. The difference between the above two engines hp is negligible. In real life they will be essentially the same speed (assuming similar weight MHs)

The two curves are a secondary or tertiary factor. In real life both drivers will get to essentially the same hp and essentially the same rate of energy transfer at approximately the same time. They will then settle in for the long haul up the hill at essentially the same speed.

Comparing the two torques for hill climbing is misleading and shows a lack of understanding about the speed at which a mh climbs a big hill.

If you want to go fast get a 500 or 600 hp engine not an engine with 20 more hp or drive a corvette



Obviously, my point was either not made, or wasted (on you). But, since we disagree on a couple of your statements, I will now quit. I'm not at all interested in basic term definitions that don't apply. Selecting a diesel engine for a production diesel pusher, if you want maximum performance, is a no-brainer.


Posted By: DanTheRVMan on 11/16/11 10:15am

wolfe10 wrote:

I am a little hesitant to get into this HP/torque discussion, but here goes anyway.

There are high torque/low RPM engines-- diesels.

There are medium torque/medium RPM engines-- gasoline.

There are very low torque/very high RPM engines-- turbine/jet.

The same HP produced by each will push the same coach up the same grade at the same speed.

The difference is that the diesel engine can do that at an RPM that is can safely sustain for hours at a time. Not so the HP of a gasoline engine-- its peak HP is at too high an RPM to safely run for extended periods of time.

But, though I own and like a diesel, I would be the first to say that I could have driven a gasoline powered coach 100% of the places I have driven our diesel. Yes, a little slower and using more fuel, but at lower initial cost.


YES


Posted By: DanTheRVMan on 11/16/11 10:18am

Cloud Dancer wrote:

I'm not at all interested in basic term definitions that don't apply.


How could the basic definition of POWER in physics not apply when trying to explain horse power?


Posted By: bbattey on 11/16/11 03:05pm

I've seen the light; dividing coach weight by rated HP will work to compare gas vs diesel coaches also. I was troubled by the RPM difference between the two engines going up hills, but it turns out that using HP factors that out. (Using max torque does not.) Being the physics-nerdy type, I crunched some numbers using the GM 8.1L gasser, 340 HP @ 4200 rpm & 455 ft-lb @ 3200, and a version of the isc I found online, 330 hp @ 2100 RPM & 1150 lb-ft @ 1300 RPM. Rated HP of these engines is within 3% of each other. I did my calculations assuming everything identical except engines and gear ratios. I assumed the hill was steep enough that both coaches were at full throttle. The answer I got was that the torque delivered to the wheels was within 2% of each other.

DantheRVMan, I now agree with you (and wolfe10). All coaches can be compared for hill climbing ability by dividing total weight by the rated HP numbers.

One big caveat to comparing hill climbing ability this way is that it assumes both coaches are appropriately geared, as rgatijnet1 points out. I suspect the diesels with 4 speed Allisons are losing some hill climbing speed due to not having a gear to match the engine's torque curve.

Mr. Mark- Sorry for making your eyes bleed, and sorry to the rest of you for going too physics-nerdy on you. I got a little off track there.


Posted By: pnordan on 11/16/11 03:36pm

I have a 275 Cummings in a 38' coach at about 22,000#. We tow a Dodge 1500 4x4 a weighing around 6000#. It is not great in a 'break away' from a stop but performs very well after about 15 -20 mph. We just did a 1 year 13,000 mile trip from NC to MT and back, then down to Gulf Coast and out to NV up to CO and back to NC. The MPG was good for what we asked of the unit, usually 9-10 unless we had one of those strong SD head winds.


Paul & Kristina
Lucy & Curly
2004 American Coach Tradition
2004 jeep Grand Cherokee



Posted By: DanTheRVMan on 11/16/11 04:01pm

bbattey wrote:

I've seen the light; dividing coach weight by rated HP will work to compare gas vs diesel coaches also. I was troubled by the RPM difference between the two engines going up hills, but it turns out that using HP factors that out. (Using max torque does not.) Being the physics-nerdy type, I crunched some numbers using the GM 8.1L gasser, 340 HP @ 4200 rpm & 455 ft-lb @ 3200, and a version of the isc I found online, 330 hp @ 2100 RPM & 1150 lb-ft @ 1300 RPM. Rated HP of these engines is within 3% of each other. I did my calculations assuming everything identical except engines and gear ratios. I assumed the hill was steep enough that both coaches were at full throttle. The answer I got was that the torque delivered to the wheels was within 2% of each other.

DantheRVMan, I now agree with you (and wolfe10). All coaches can be compared for hill climbing ability by dividing total weight by the rated HP numbers.

One big caveat to comparing hill climbing ability this way is that it assumes both coaches are appropriately geared, as rgatijnet1 points out. I suspect the diesels with 4 speed Allisons are losing some hill climbing speed due to not having a gear to match the engine's torque curve.

Mr. Mark- Sorry for making your eyes bleed, and sorry to the rest of you for going too physics-nerdy on you. I got a little off track there.


Glad to hear it and very impressed with your post. We all make mistakes and get things wrong from time to time.

One of my concerns is sales people mislead and people are scared into buying a rig they really don't need. An upgraded rig can run an additional $40k +/- That is a big dent in the average joes retirement fund.

Are there other advantages to diesel or a bigger diesel with more torque - yes. But that does not mean the hp in a more basic coach will not go up a hill quickly.


Posted By: missscarlet9 on 11/16/11 07:27pm

And....here's my 2 cents worth. All of the technical information on the posts to this forum is right on. My recommendation to anyone out there considering a DP vs. gas....get in, turn the key and gauge it for yourself.

I love my 260 Cummins (cranked up to 300 hp). Good pull, great mileage. This is after owning 3 non diesel class A motorhomes.

The big calculation for me was not necessarily the technical data: torque curve vs. hp vs barometric pressure (just an example). It was more: Cost of purchase vs. cost of maintenance vs. cost of fuel vs. my WANTS. We all justify the ownership in our own way.

I think most RVers are similar to me in this respect..we haul what we can. If I had 500 hp, I would load the MH to haul it.

I'll NEVER own another gas M.H.

* This post was edited 11/16/11 07:38pm by missscarlet9 *


Livin' the dream!



Posted By: snickster on 11/16/11 08:22pm

I have had this current coach with the 275 HP engine for 14 years.
The coach is lightweight and easily exceeds the old guidelines of needing at least 10 HP for every 1000 lbs of weight.

Currently I tow a Jeep Wrangler with no strain. Normally I have no problem keeping up with my friends who have 400-500 HP engines and drive 75 mph.
I did tow a ford Explorer and thought it was heavier that I preferred.

The long upgrades are slow going, but we travel in the Rockies every year.

By all means get a bigger engine/coach if it's in the budget and you want it , however I have been pleased with my 275 hp Cunnins for a long time. I bought a larger coach and kept it 4 years and sold it and kept the one you see in my signature. The only thing I miss is the larger bathroom and wish we had at least one slide in the bedroom.

There are some great buys out there on Cummins ISB coaches from that era. Just look for one that has been taken care of.


The snickster
Mark and Priscilla
98 HR ENDEAVOR 37 WDS Diesel
Jeep Wrangler Toad
THE YORKIES : Winston , Abby, Izzy


Posted By: Mr.Mark on 11/16/11 09:13pm

bbattey wrote:

Mr. Mark- Sorry for making your eyes bleed, and sorry to the rest of you for going too physics-nerdy on you. I got a little off track there.


LOL... I hope I didn't offend you but when posts get long and wordy, my eyes cross and its hard to read. I'm not physics minded and I start to get sleepy reading all that. I'm sure there are people that hang on every word which is good. Some people are very detail oriented and make good gear-heads which I am not.

Safe Travels,
MM.


Posted By: Cloud Dancer on 11/16/11 09:26pm

DanTheRVMan wrote:

Cloud Dancer wrote:

I'm not at all interested in basic term definitions that don't apply.


How could the basic definition of POWER in physics not apply when trying to explain horse power?



What I said is in the context of selecting a diesel pusher with an engine that will deliver the performance that will satisfy a person who is interested in performance that's significantly better than their previous motorhome,......as in someone who is upgrading from a front-engined gas MH to a diesel pusher that's significantly heavier than their gas unit.
And, I'm saying that all you need to do is look at the GVWR and the engine torque. My magic number is 30-1/2 or less lbs of weight per pound of engine torque.

I repeat:
I myself am NOT interested in basic term definitions that do not apply.

This means that I recognize everyone's freedom to use whatever method works for them.

Also, keep in mind that there's others that think along the same lines as I do in seeing high engine displacement and high torque as vital requirements in this selection process. We all know that the engine dyno first senses the torque, and then the horsepower is computed using the standard forumula. The definition of HP, and the appropriate math, is useful if you were trying to determine the acceleration of a known weight and body design of motorhome going up a known grade in known conditions. You know, like a textbook problem.
I've done that too, but it certainly is not necessary for accomplishing what I've talked about above, regarding subject context.

This is what a guy wrote early on THIS thread:

"I hate to re-open an issue that has been discussed many times before, but not all diesel engines with the same rated HP are the same because the torque is different. Torque is almost totally a function of engine size in these diesels and pretty much cannot be changed, but for a given engine size, changes in the ECM can alter the HP output a bit. As a result there are MH's advertised as having 400HP most of which have Cummins ISC engines, some have the Cummins ISL engine, and a few have the ISM. The ISC engine produces ~1050 ft lbs of torque, the ISL is ~1200, and the ISM is ~1500. Guess which one goes up the hill fastest? (Roughly the same is true of the CAT C-7, C-9, and C-12 engines).

We just came back from a summer in WY, MT and ID. Pulling our toad we are ~37,000 pounds with 1550 ft-lbs of torque and "only" 425 HP. Going up hills I hardly ever use the truck lane since we can climb faster than all the trucks and a lot of the smaller cars! LOL "


Posted By: wny_pat on 11/16/11 10:40pm

missscarlet9 wrote:

And....here's my 2 cents worth. All of the technical information on the posts to this forum is right on. My recommendation to anyone out there considering a DP vs. gas....get in, turn the key and gauge it for yourself.

I love my 260 Cummins (cranked up to 300 hp). Good pull, great mileage. This is after owning 3 non diesel class A motorhomes.

The big calculation for me was not necessarily the technical data: torque curve vs. hp vs barometric pressure (just an example). It was more: Cost of purchase vs. cost of maintenance vs. cost of fuel vs. my WANTS. We all justify the ownership in our own way.

I think most RVers are similar to me in this respect..we haul what we can. If I had 500 hp, I would load the MH to haul it.

I'll NEVER own another gas M.H.
Now here is the voice of common sense! Besides, anyone who can design the Frankenshower knows what they are talking about!!! Loved it. Nothing fancy and it appears to work great.


Posted By: DanTheRVMan on 11/17/11 03:22am

Cloud Dancer wrote:


Also, keep in mind that there's others that think along the same lines as I do in seeing high engine displacement and high torque as vital requirements in this selection process.


I know that is the problem.

The higher engine torque of the isc means it is less likely to need to down shift or down shift as much as an isb engine. But they both have essentially the same hp and will maintain essentially the same speed. The isb will just need a lower gear from time to time due to its lower torque.

I don't really hear the engine much in my pusher so I do not view the torque as vital.

It is perfectly fine if you view high torque as vital. It is wrong if you tell people engine torque determines speed not HP.


Posted By: Cloud Dancer on 11/17/11 05:58am

DanTheRVMan wrote:

Cloud Dancer wrote:


Also, keep in mind that there's others that think along the same lines as I do in seeing high engine displacement and high torque as vital requirements in this selection process.


I know that is the problem.

The higher engine torque of the isc means it is less likely to need to down shift or down shift as much as an isb engine. But they both have essentially the same hp and will maintain essentially the same speed. The isb will just need a lower gear from time to time due to its lower torque.

I don't really hear the engine much in my pusher so I do not view the torque as vital.

It is perfectly fine if you view high torque as vital. It is wrong if you tell people engine torque determines speed not HP.



In that case I'm innocent as charged. What I have said previously (not on this thread), is that you can say that it's THRUST that propels a vehicle (even a motorhome), and if you want more speed simply increase the thrust. BTW the formula for converting drive-wheel torque to thrust is pretty straight forward (doesn't even mention horsepower).

Back to the OP and his inquiry: We've answered it several times, my first answer came early in the thread. My second version goes like this: For some of us experienced ole-timers, if the GVWR vs engine torque specs for our diesel pusher produce a number higher than 30-1/2 lbs of weight per lb of torque, we're going to need a bigger engine.
Speaking for myself, I got sick with the low performance and loud high-pitch noise of all my five gasoline-engined motorhomes. I got passed way too many times going up grades, by big diesel pushers whose engines sounded like they weren't turning more than 1,800 RPM, while mine was screaming at 4K plus RPM.
I made sure I finally ended up with a big diesel pusher with a big enough engine, with enough torque, whereby it didn't have to shift down all the time. I hated THAT! Of course, I also insisted on a side radiator with variable-speed hydraulic motored fan. I love normal conversations in the cockpit. BTW it's one big reason I love bypass turbine engines in aircraft.


Posted By: DanTheRVMan on 11/17/11 06:32am

Cloud Dancer wrote:


In that case I'm innocent as charged. What I have said previously (not on this thread), is that you can say that it's THRUST that propels a vehicle (even a motorhome), and if you want more speed simply increase the thrust. BTW the formula for converting drive-wheel torque to thrust is pretty straight forward (doesn't even mention horsepower).



Cloud Dancer,

I am glad you enjoy your very nice MH.

But, why don't you stop the double speak "doesn't even mention horsepower"

Weight and hp will determine the speed of a MH. If you understand basic physics you have to agree. If you don't....

LOTS of people have budgets and they do not need people confusing them about speed. Most people either never took physics or do not remember any physics.

Yes lower torque engines will rev higher and be noisier but that doesn't mean they will be slower. In my pusher I do not notice this revving and noise.

I would not recommend people blow their budget or not buy and RV due to a little bit of noise on the occasional hill.

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Currently, I am more interested in retiring earlier with more money than I am in giving more money to MH manufacturers. For me I am more interested in making sure the cost of the MH is a small percentage of my assets. Others are free to spend as they wish. But either way the physics is always the same.


Posted By: wny_pat on 11/17/11 09:05am

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Posted By: Mr.Mark on 11/17/11 09:21am

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Now this guy is making sense!

MM.


Posted By: Cloud Dancer on 11/17/11 09:25am

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


The Foretravel IH45 has a GVWR of 54,000 lbs, which results in a weight/torque number of 27-1/2 lbs of weight per lb of engine torque.

Whereas, the nice-looking Forest River Berkshire is 42-1/2 lbs of weight per lb of engine torque.

My Dutch Star is 30-1/2 lbs of weight per lb of engine torque. Mine performs very well, but Yeah, I want that Foretravel. But, I too suffer from insufficient funds.


Posted By: DanTheRVMan on 11/17/11 10:02am

Mr.Mark wrote:

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Now this guy is making sense!

MM.


You guys are FUNNY

lets see 54000/650 is 83 lb/hp and my Red is 33000/340 or 97 lb/hp so you are correct that will be pretty fast for a MH.

But I am a simple guy. I play some tunes and sing some songs and enjoy my ride up the mountain.

Remember the penalty for going slow is you have to spend more time in awe viewing all these beautiful mountain vistas around the country. Going out to view the scenery is kinda why I bought the MH in the first place so I really do not see it as a penalty.

Maybe I could make a few extra bucks teaching remedial physics at campgrounds in my spare time and save up for it.


Posted By: DanTheRVMan on 11/17/11 11:01am

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


How much does that silly thing cost? I am not familiar with it.


Posted By: Mr.Mark on 11/17/11 11:03am

DanTheRVMan wrote:

Mr.Mark wrote:

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Now this guy is making sense!

MM.


You guys are FUNNY

lets see 54000/650 is 83 lb/hp and my Red is 33000/340 or 97 lb/hp so you are correct that will be pretty fast for a MH.

But I am a simple guy. I play some tunes and sing some songs and enjoy my ride up the mountain.

Remember the penalty for going slow is you have to spend more time in awe viewing all these beautiful mountain vistas around the country. Going out to view the scenery is kinda why I bought the MH in the first place so I really do not see it as a penalty.

Maybe I could make a few extra bucks teaching remedial physics at campgrounds in my spare time and save up for it.


Dan, please don't bring logic into this, I want the Foretravel IH-45!!!.... sweet coach or maybe the Newell.

MM.


Posted By: Cloud Dancer on 11/17/11 11:27am

The base price for the Foretravel IH-45 is $1,175,000.
The base price for the Newell is $1,411,500. Its performance-reference number is 32-1/2 lbs of weight per lb of engine torque.

Personally, I'm attracted to the new WInnebago Tour 42JD, at base price of $351,098. Its performance-reference number is 35-1/5 lbs of weight per lb of engine torque. Yep, for this level of design and construction quality, and features, I would be willing to act my age and give up a little bit of acceleration.


Posted By: DanTheRVMan on 11/17/11 11:48am

Mr.Mark wrote:

DanTheRVMan wrote:

Mr.Mark wrote:

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Now this guy is making sense!

MM.


You guys are FUNNY

lets see 54000/650 is 83 lb/hp and my Red is 33000/340 or 97 lb/hp so you are correct that will be pretty fast for a MH.

But I am a simple guy. I play some tunes and sing some songs and enjoy my ride up the mountain.

Remember the penalty for going slow is you have to spend more time in awe viewing all these beautiful mountain vistas around the country. Going out to view the scenery is kinda why I bought the MH in the first place so I really do not see it as a penalty.

Maybe I could make a few extra bucks teaching remedial physics at campgrounds in my spare time and save up for it.


Dan, please don't bring logic into this, I want the Foretravel IH-45!!!.... sweet coach or maybe the Newell.

MM.


Mark,

I'm just trying to figure out a plan to pay for it. I figure I need 120,000 to 140,000 remedial physics students at $10 each. Or one student willing to pay 1.4 million for a remedial physics class.


Posted By: docj on 11/17/11 01:33pm

Cloud Dancer wrote:

The base price for the Foretravel IH-45 is $1,175,000.
The base price for the Newell is $1,411,500. Its performance-reference number is 32-1/2 lbs of weight per lb of engine torque.

Personally, I'm attracted to the new WInnebago Tour 42JD, at base price of $351,098. Its performance-reference number is 35-1/5 lbs of weight per lb of engine torque. Yep, for this level of design and construction quality, and features, I would be willing to act my age and give up a little bit of acceleration.


That's why I bought mine used. With a GVWR of 32,400 and 1,550 ft-lbs of torque, I believe that comes out to 20.9 lbs of MH for every ft-lb of engine torque. Even with a ~4,000 lb toad the number stays <23.5.

We couldn't have afforded this one new, let alone the Foretravels or Newells. But with a well-cared for CAT engine with <70,000 miles (of which we've put on 15,000) I figure we'll have plenty of fun times. We spent most of the summer in and around the Rockies at altitudes of up to 9,200 ft. This is definitely a fun beast to drive in the mountains. On the steepest hills, if I downshift to 4th to avoid "hunting" by the transmission I can run with just about anything on the road. 4th puts the engine at about maximum HP output at ~55 mph and it will take whatever I give it without raising engine temp more than 2 degrees.

I hope everyone understands that all I am saying is that this MH is fun for us. I'm not advocating that everyone buy a coach that is this overpowered or that it makes it superior to one that has less power. All I'm saying is that a "souped-up" MH can be a lot of fun to drive, if you like that sort of thing. My wife and I both used to enjoy driving powerful cars; this is just a way of continuing the fun.


Posted By: 2inAlabama on 11/17/11 06:01pm

I am looking at a 2000 Monaco Knight which has a ISB 260 engine with only 30k miles on it. The coach has a GVWR of 22000 lbs. Anyone here have experience with this engine/coach combination? We are planning to do a lot of traveling in the western US. How will this rig take the mountains towing a 3000# toad?

Any input appreciated.


Just DH & DW
Shopping for a Foretravel U320 42 ft



Posted By: Jarlaxle on 11/17/11 06:35pm

An ISB in a 22,000lb coach will go pretty well...not a rocket, but hardly underpowered. Bonus: should return pretty good fuel mileage.


Posted By: DanTheRVMan on 11/17/11 06:38pm

2inAlabama wrote:

I am looking at a 2000 Monaco Knight which has a ISB 260 engine with only 30k miles on it. The coach has a GVWR of 22000 lbs. Anyone here have experience with this engine/coach combination? We are planning to do a lot of traveling in the western US. How will this rig take the mountains towing a 3000# toad?

Any input appreciated.


I do not have personal experience, but

22000 + 3000 = 25000lbs

25000/260= 96 lbs/hp

It is better than the general rule of thumb of not more than 100lbs/hp. So based on that it should not be poor. It should go up the hills reasonably well like most other MHs, but speed up hill is not MHs forte. Unless of course, you want to spend over a million dollars like some individuals would like to see under their Christmas tree next month.


Posted By: Mr.Mark on 11/17/11 07:00pm

Our coach still seems new and we just got a compliment from our RV neighbor that they thought it was new. I do keep it waxed and clean.

Three coaches have caught my eye for a possible future replacement...
- Newmar King Aire
- Foretravel IH-45
- Newell

In the Foretravel, every floorplan I've seen does not have two sofa's across from each other... although I would rather have recliners/sofa like we have. They have a dinette booth across which you lose a lot of seating for guests.

The Marathon Prevost conversion units that are offered only offer a 515 hp Detroit Diesel. I just can't imagine that coach having any power at over 50,000 lbs. We toured their factory in Sept. of '10.

I don't think I'll keep our current coach 10 yrs so we'll see what happens as I'm thinking maybe of a 2014 model (new). Our current coach is our first so I now have a very clear mind on what I want in our next coach. I would like the 650 hp Cummins if available; in a few years who knows what will be offered?

MM.

* This post was edited 11/17/11 07:08pm by Mr.Mark *


Posted By: missscarlet9 on 11/17/11 07:15pm

2inAlabama wrote:

I am looking at a 2000 Monaco Knight which has a ISB 260 engine with only 30k miles on it. The coach has a GVWR of 22000 lbs. Anyone here have experience with this engine/coach combination? We are planning to do a lot of traveling in the western US. How will this rig take the mountains towing a 3000# toad?

Any input appreciated.


That is exactly what I currently own. Be award of the motor. Take this as SOLID advice, you HAVE to check the engine block for a #53 block. Google it to find out how. The block is known to be flawed and WILL crack over time if it hasn't already done so. The block will crack behind the turbo just below the top of the block. Don't assume anything.

How do I know, it happened to me which cost me a complete engine replacement. Any other block casting # is great. It's strong and has very good fuel economy.

Oh and...I added +40hp injectors and the rig pulls considerable better. By the way, the wife and I love it now!

* This post was edited 11/17/11 07:35pm by missscarlet9 *


Posted By: missscarlet9 on 11/17/11 07:30pm

Mr.Mark wrote:

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Now this guy is making sense!

MM.


And (as they used to say in the 70's) with a machine like that, you can pass everything but the fuel pumps!


Posted By: DanTheRVMan on 11/18/11 05:07am

missscarlet9 wrote:

Mr.Mark wrote:

wny_pat wrote:

DanTheRVMan wrote:

If I ever upgrade from my Red (isb engine) to a Phaeton (isc engine) it will likely be SLOWER. HP is roughly the same but the phaeton is a lot heavier and is likely a slight bit SLOWER.

I am not against people buying or preferring bigger and better MHs if that is what they want. I am against the misinformation that you HAVE to spend big bucks for higher torque engines or your MH will be to slow.

Then instead of upgrading to the Phaeton, you should consider the Foretravel IH with the ISX, 650 H.P. and with 1950 lb–ft torque. Then you could run with the big boys!


Now this guy is making sense!

MM.


And (as they used to say in the 70's) with a machine like that, you can pass everything but the fuel pumps!


If you can afford a 1.2 million dollar coach I do not think you worry about fuel costs very much.


Posted By: DanTheRVMan on 11/18/11 05:29am

Mr.Mark wrote:

Our coach still seems new and we just got a compliment from our RV neighbor that they thought it was new. I do keep it waxed and clean.

Three coaches have caught my eye for a possible future replacement...
- Newmar King Aire
- Foretravel IH-45
- Newell

In the Foretravel, every floorplan I've seen does not have two sofa's across from each other... although I would rather have recliners/sofa like we have. They have a dinette booth across which you lose a lot of seating for guests.

The Marathon Prevost conversion units that are offered only offer a 515 hp Detroit Diesel. I just can't imagine that coach having any power at over 50,000 lbs. We toured their factory in Sept. of '10.

I don't think I'll keep our current coach 10 yrs so we'll see what happens as I'm thinking maybe of a 2014 model (new). Our current coach is our first so I now have a very clear mind on what I want in our next coach. I would like the 650 hp Cummins if available; in a few years who knows what will be offered?

MM.


Mark,

I know you do not want logic, but you seem like a nice guy so I am going to give it to you any way.

I have had several clients that owned porsche's and exotic cars. They always said the exotics were fun, but not reliable like the porsche for every day use.

Before I dropped a million +/- on a coach I would want to make sure I got the best designed most problem free coach not necessarily the one with the most hp. I do not know much about the coaches you mentioned so I can not say which is the best. It may be the one with the most hp. I simply do not know.

They all seem like very nice MHs. I'm just saying consider everything not just hp. Then just have fun with it.


Posted By: Cloud Dancer on 11/18/11 05:56am

Logic? How about fun?

My favorite is the gratification part. Like good enough acceleration such that getting on the interstate is no problem because I can join traffic at a higher speed than what they're going (or is it that they get scared and slow down for you.....).
Then, there's the part where you stop at Walmart, and sleep in your own king-sized bed:





Posted By: michahicks on 11/18/11 06:25am

Cloud Dancer wrote:

Logic? How about fun?

My favorite is the gratification part. Like good enough acceleration such that getting on the interstate is no problem because I can join traffic at a higher speed than what they're going (or is it that they get scared and slow down for you.....).
Then, there's the part where you stop at Walmart, and sleep in your own king-sized bed:




Thus making the "different strokes" point once again...


Posted By: DanTheRVMan on 11/18/11 08:36am

DanTheRVMan wrote:

Then just have fun with it.


I do hope he has fun with it and I said so.

I just do not want Mark to forget about the FUN of waiting at a repair shop for some widget to get fixed.

Or the FUN of trying to get parts for an orphan because the manufacturer filed for bankruptcy.


Posted By: Mr.Mark on 11/18/11 09:03am

DanTheRVMan wrote:

DanTheRVMan wrote:

Then just have fun with it.


I do hope he has fun with it and I said so.

I just do not want Mark to forget about the FUN of waiting at a repair shop for some widget to get fixed.

Or the FUN of trying to get parts for an orphan because the manufacturer filed for bankruptcy.


Yeah, I know what you mean, it's no fun waiting in a repair shop which we have never really had to do. We have never broken down in our coach and hope it never happens. We have had to order parts before but it never kept us off the road. And, our coach is not orphaned so tech support and parts are plentiful.

Any new coach from any manufacture in any price range can give you headaches or be mostly trouble free. You really never know until you buy it.

I have a couple exotic cars, one old, one new along with others that I bought and have held onto and the new one has been trouble free with it's W-12 twin turbo engine and 552 hp, AWD.... but, tomorrow is always another day.

MM.


Posted By: Dog Trainer on 11/18/11 10:21am

DanTheRVMan wrote:

Mr.Mark wrote:

Our coach still seems new and we just got a compliment from our RV neighbor that they thought it was new. I do keep it waxed and clean.

Three coaches have caught my eye for a possible future replacement...
- Newmar King Aire
- Foretravel IH-45
- Newell

In the Foretravel, every floorplan I've seen does not have two sofa's across from each other... although I would rather have recliners/sofa like we have. They have a dinette booth across which you lose a lot of seating for guests.

The Marathon Prevost conversion units that are offered only offer a 515 hp Detroit Diesel. I just can't imagine that coach having any power at over 50,000 lbs. We toured their factory in Sept. of '10.

I don't think I'll keep our current coach 10 yrs so we'll see what happens as I'm thinking maybe of a 2014 model (new). Our current coach is our first so I now have a very clear mind on what I want in our next coach. I would like the 650 hp Cummins if available; in a few years who knows what will be offered?

MM.


Mark,

I know you do not want logic, but you seem like a nice guy so I am going to give it to you any way.

I have had several clients that owned porsche's and exotic cars. They always said the exotics were fun, but not reliable like the porsche for every day use.

Before I dropped a million +/- on a coach I would want to make sure I got the best designed most problem free coach not necessarily the one with the most hp. I do not know much about the coaches you mentioned so I can not say which is the best. It may be the one with the most hp. I simply do not know.

They all seem like very nice MHs. I'm just saying consider everything not just hp. Then just have fun with it.

Hmm questioning a foretravel design and problems. I think I'll take my chances there.


93 Airstream 35' Dp
5.9 230 uprated to 300 HP
Allison MD 3060
Shadow 12 yr old Golden Daktari & Lydia Cavalier King Charles (fur Bearing Children) Duchess my Golden daddys little girl at the Rainbow bridge since 4/12



Posted By: DanTheRVMan on 11/18/11 10:56am

Dog Trainer wrote:

Hmm questioning a foretravel design and problems. I think I'll take my chances there.


If you want a high quality reliable product you are generally better off with a high quality production line product like mercedes, lexus, honda, others. (I am aware there are low quality production lines out there.)

Hand crafted items or small production items generally have more problems than high quality production lines with good process control. It is pretty well documented and I have friends that are quality engineers who can cite the studies a whole heck of a lot better than I can.

So yes I have nothing against foretravel or the others, but you had better expect some level of trouble with all of them. Same is true of all MH production though. There are no MH manufacturers that produce product comparable to high quality automotive products.

That said I would not mind owning any of the three Mark likes.


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