Why can't gas engines be in the rear, or why can't they be front wheel drive?

[ga traveler]

Originally Posted by botiemad

No. There were over 100 MH manufacturers in 1978, only 20 survived. Winnebag had just invested $$$ in propane powered RVs but the industry was collapsing. The first OPEC embargo was 1970, then came the one in '79. The photo I saw was taken from the air and it showed 100s and 100s of complete Winnebagos (mostly Itascas) sitting unsold in the Winnebago compound. I assume they were scrapped.

There was photo's from the air of the town and almost every house had a couple or three motorhomes sitting in the yard. Most of the people worked for Winnebago and they had no place to store the motorhomes. To winnebagos credit they did not shut down. They were building motorhomes that there was no market for. They let the employees park them in their yards. Thankfully Winnebago had very deep pockets and were able to weather the downturn. All the units were sold at deep discounts. Open Road was making a very good motorhome, However they did not have reserve funds. They sold all their motorhome inventory at 50% of the normal dealer price. Our dealership bought several before they totally collapsed.

[CACOrange]

Horsepower is horsepower that's is very true but horsepower isn't torque and an engine with high horsepower but low torque (gas engines) can't perform as well as a diesel when pushing 10s of thousands pounds of weight.
Torque will out perform horsepower on hills and acceleration on a motorhome. Diesel, by the most part has higher torque than gassers therefore are more suited to motorhome.

[CACOrange]

Exactly

[nothermark]

Not really. Moreover the equivalent gas engine will have a wider RPM range so need fewer gears to do it. I really don't think the DP folks have a clue what their transmission is doing. There is a reason equivalent trucks have a 12 - 18 speed shift range.

If you go back a few pages I think you will find somebody pointing out that GM could not get the big gas engine past the early EPA standards. Makes some sense when the standard was set as x number of grams/mile of pollutant. Bigger engines needed more cleanup. That set a limit on size.

[darstar]

Originally Posted by nothermark

Not really. Moreover the equivalent gas engine will have a wider RPM range so need fewer gears to do it. I really don't think the DP folks have a clue what their transmission is doing. There is a reason equivalent trucks have a 12 - 18 speed shift range.

If you go back a few pages I think you will find somebody pointing out that GM could not get the big gas engine past the early EPA standards. Makes some sense when the standard was set as x number of grams/mile of pollutant. Bigger engines needed more cleanup. That set a limit on size.

Not so anymore......the days of small displacement diesels is over. Today we can match the MH to the appropriate engine. What drove the attempt using small diesels in giant boxes with windage was better fuel mileage. And ,when you get into the high end / more bus like units that weigh 50k or more there the choice totally disappears.

[Woody57]

Originally Posted by mtofell

I think it just comes down to cost. Ford manufacturers the chassis they way they do and that's all the MH manufacturers have to work with. RVs are a REALLY small segment of the market for larger truck chassis.



There have been some gas pushers before and some diesel engines in the front but they are rare. Some of the old GMC bubble like class A rigs (like the one in the movie Stripes) were FWD. A friend's dad had one and loved it. The ground clearance was like 4". A total nightmare to do any work on.

We had a 78 GMC and she was a great coach. Traveled the us and never missed a beat. Don’t remember being a nightmare to work on but was a lot younger then. Still one of the best looking 28 foot coaches out there

[bjohnmasters]

Originally Posted by Crasher

With the diesel comes the comfort of an air ride suspension and a bullet proof Allison to say nothing of the increased capacity.

So I'm new around here, but have always wondered, why couldn't there be air ride suspension on a gasser?

[stepside454]

Originally Posted by bjohnmasters

So I'm new around here, but have always wondered, why couldn't there be air ride suspension on a gasser?

Its already been mentioned in this thread

[saddlesore]

Originally Posted by nothermark

Not really. Moreover the equivalent gas engine will have a wider RPM range so need fewer gears to do it. I really don't think the DP folks have a clue what their transmission is doing. There is a reason equivalent trucks have a 12 - 18 speed shift range.

.

Ummm...I have owned and driven gas powered over the road (class 7/8) trucks . (several 6 cylinder Hall-Scott's, Black/Red/Green Diamond International's and 534ci Fords... all with multiple transmissions)
No emission standards back then, and was really happy if I got 2 to 3 MPG...


There are no readily available gas "over the road" engines that will develop the needed continuous/sustained torque to maintain highway speeds and are able to produce an acceptable gas mileage as compared to a diesel in a class 6/7/8 trucks or when applied to the over 36,000 lb motor coaches/5'r tow rigs..

There has been a little bit of success in converting diesels to natural gas, however the fuel mileage suffers to the point that without government support, is not financially cost effective.


Bottom line is that modern gas engines cannot and will not produce enough constant/sustainable torque to move a 36,000 lb truck or RV on today's modern highways and interstate systems.... regardless of what kind of transmission is used....

[DryCreek]

Originally Posted by nothermark

Not really. Moreover the equivalent gas engine will have a wider RPM range so need fewer gears to do it. I really don't think the DP folks have a clue what their transmission is doing. There is a reason equivalent trucks have a 12 - 18 speed shift range.

If you go back a few pages I think you will find somebody pointing out that GM could not get the big gas engine past the early EPA standards. Makes some sense when the standard was set as x number of grams/mile of pollutant. Bigger engines needed more cleanup. That set a limit on size.

I see the advantage of diesel engines over gas - they produce their "power" at a lower RPM. That's why we have a diesel pickup to haul our hay/cattle/equipment/etc. I love a diesel engine.


but....


We have a V-10 gasser motor home. It spins at a higher RPM, but is also half the price of a comparable motor home in its size. That being said, I would love to find a 32' motor home with an ISB (CP3/CRI). I like the Winnebago/Itasca 32T (except for the refrigerator being in the slide). I have one bookmarked up in Oklahoma. We may go take a look at it next week.


but...….


Also having an engineering background, I do realize that he torque argument is moot. What is the definition of "work" (W)? The ability to apply a force over a distance. What is the definition of "torque"? The work that can be exerted over a distance (or, work in a rotational direction). What is the definition of Horsepower? The rate at which work is applied. When you look at reciprocating internal combustion engines and realize that torque and horsepower curves will always cross at 5,200 RPM, then you understand that the only difference between the two types of propulsion are the RPM band where they make their power - or the ability to exert a force over a distance (torque) at a given rate. The comparison between gassers (max GCVWR of 26K lbs) to a DP are quite moot (GVWR of 40k and higher). The ISX in 12L to 15L displacement is as different as apples to oranges. When comparing fuel types, why don't we limit the comparison to like-displacements, such as the ISB (5.9L or now 6.7L) or the MaxxFarce?

[ScoobyDoo]

Originally Posted by nothermark

Not really. Moreover the equivalent gas engine will have a wider RPM range so need fewer gears to do it. I really don't think the DP folks have a clue what their transmission is doing. There is a reason equivalent trucks have a 12 - 18 speed shift range.

A diesel will normally run at lower RPM, which should slow wear, but the higher compression ratios means the engine must be built heavier. As far as the many gears in transmissions; I had 3 Macks '78 +'79. 2 had 5 speeds, 1 was 6. (the extra gear was deep reduction for off road use) The trucks all did a good job running 60,000 to 80,000. And the 6 speed with the owner driving, delivered a lot of loads grossing near 130,000.
And from what I have heard they are putting more gears behind the gas engines.

[DryCreek]

Originally Posted by ScoobyDoo

I had 3 Macks '78 +'79. 2 had 5 speeds, 1 was 6. (the extra gear was deep reduction for off road use) The trucks all did a good job running 60,000 to 80,000. And the 6 speed with the owner driving, delivered a lot of loads grossing near 130,000.
And from what I have heard they are putting more gears behind the gas engines.

I was going to mention the Maxidyne/Maxitorque 5 speed drivelines available in the 70's. Saw many a yard dog with that setup, and quite a few 8 to 10 yard dumptrucks too!

[Roy1]

Originally Posted by bjohnmasters

So I'm new around here, but have always wondered, why couldn't there be air ride suspension on a gasser?

My 40 year old GMC was front wheel drive had torsion bar front suspension and total air suspension in the rear. It was a dream to drive almost like driving an older Cadillac. The ride was noticeably smoother then my Country Coach which is full air suspension. All 6 wheels on the GMC were independent suspension .

[Charles27909]

Originally Posted by poppopc

Guess my question why can't there be air suspension standard ,on a gas coach?
A lot of owners add them after market.

I have so often wondered the same. An on board air compressor and regular air ride suspension hardware is the only things needed....oh and about a $5,000 - $10,000 increase in price. But I would argue that would be welcomed when compared to the total upgrade cost going from gas to diesel pusher. Factory air ride on gas powered units would fill a void in the market left open for people desiring air ride but a big diesel pusher may be out of the budget.

Personally, I am a fan of converted buses. Built heavy, built to last, and hold up very well over time and doesn't go into a gazillion pieces if involved in a wreck.