Enough Power

ejm · August 11, 2020

Looking at a 40" 3-slide MH with a 330hp diesel. Is this enough power to pull in the Rocky Mountains or should I look for a 400hp? Had a fifth wheel that I pulled with a 6.7 Ford diesel, total weight around 24k. MH is about 32-35k.

jcussen · August 11, 2020

No one ever complained, "I have too much horsepower". At 35000 lbs, you would be on the wrong side of the one hp per thousand lb rule. You will still get there, but probably not as fast as your fifth wheel, but many do get by with lower horsepower rigs..

Kirk W · August 11, 2020

1 hour ago, ejm said:

Is this enough power to pull in the Rocky Mountains or should I look for a 400hp?

Enough power is a very subjective thing. Back in the 1990's it was quite common for class A motorhomes to be powered by a 275 hp engine and they went everywhere that most of us go today. It is true that most of them were in the high 35' to 38' in length and weighed less than yours but with proper gearing and the patience the owners went everywhere with them. So the question is not if that 330 engine won't get you up a steep grade at racing speeds but it will get you there. Will it bother you if you do hold out for an RV with a 400, when some fellow with a new Cummins 600 goes roaring past you on your first mountain pass? How important is speed up a mountain grade to you?

Randyretired · August 12, 2020

In the Rocky Mountains because of elevation non turboed engines lose power. However a turbo diesel retains most of its power at elevation and you will have access to most of that 330 hp. Many years ago a friend called asking the same question you are and he was comparing hp ratings compared to his gas MH. To shorten the story he purchased a 40' MH with the 330 hp diesel and was thrilled that it would climb mountains as well as it did. It wasn't fast but it did okay. 400 hp would be faster and pass better but at least he was happy. I would be equally concerned with the layout as most spend more time living in it than driving. If you are towing a heavy toad or whatever that might also influence your decision.

Ray,IN · August 12, 2020

10 hours ago, Kirk W said:

Enough power is a very subjective thing. Back in the 1990's it was quite common for class A motorhomes to be powered by a 275 hp engine and they went everywhere that most of us go today. It is true that most of them were in the high 35' to 38' in length and weighed less than yours but with proper gearing and the patience the owners went everywhere with them. So the question is not if that 330 engine won't get you up a steep grade at racing speeds but it will get you there. Will it bother you if you do hold out for an RV with a 400, when some fellow with a new Cummins 600 goes roaring past you on your first mountain pass? How important is speed up a mountain grade to you?

I agree, someone always has one bigger. We once looked at a Beaver Panther with a CAT C12 engine. Our son-in-law (fleet maintenance manager for a large trucking firm) asked which was more important, getting up a mountain faster while averaging 4-5 MPG or being slower while averaging 7-8mpg.

Edited August 12, 2020 by Ray,IN

noteven · August 12, 2020

The less experienced & skilled you are driving vehicles heavier than a car, SUV, or pickup truck, the more useful "adequate" i.e. power in reserve is.

Kirk W · August 12, 2020

When Bounder first brought out their diesel pushers(1992) they were powered by a 275 Cummins engine with a 3 speed transmission that was designed for garbage trucks. Many people loved to make fun of them and call them names. There was a very active member of these forums who owned one and he loved to poke the Bounder critics. CC is no longer living but some of us will long remember the retired Houston police lieutenant. He often pointed out that it went everywhere anyone else could go, but took time to see the sights along the road and for a much lower cost to buy.

jblo · August 25, 2020

ejm, Having just changed from a 6.7 450/Suites @ 21000, you will find any MH a way different animal at acceleration--have a 380hp now that that only slowly gathers speed from a dead stop. However, it cruises easily at 60-65, just doesn't get to that speed as fast. I am a fan of HP (more the better) but 380 does ok. Personally would look for 375-400 model if possible. As mentioned, probably lot more time spent living in it than driving it...

Ray,IN · August 25, 2020

On 8/25/2020 at 12:19 PM, jblo said:

ejm, Having just changed from a 6.7 450/Suites @ 21000, you will find any MH a way different animal at acceleration--have a 380hp now that that only slowly gathers speed from a dead stop. However, it cruises easily at 60-65, just doesn't get to that speed as fast. I am a fan of HP (more the better) but 380 does ok. Personally would look for 375-400 model if possible. As mentioned, probably lot more time spent living in it than driving it...

Cummins de-rates engine HP/torque when starting from a stop to protect the transmission from damage. That statement is in my 1999 Cummins ISC engine owners manual. Yes, from a stop light it's a bit slow.

Edited August 26, 2020 by Ray,IN

stripit · August 26, 2020

I have a 340 hp diesel and yes a tad slow from a dead stop, but it will pull my Cadillac SRX up any grade I have come up to. I would always like more power, but very happy with how this performs.

jcussen · August 26, 2020

On 8/12/2020 at 8:47 AM, noteven said:

The less experienced & skilled you are driving vehicles heavier than a car, SUV, or pickup truck, the more useful "adequate" i.e. power in reserve is.

Agree, had a 40 ft 28000 lb coach with a 300 cat engine, at the on ramp I always use to get on the freeway, could only get to about 50 mph when merging onto the freeway, a pain in 75 mph freeway traffic. Traded it in a 29000 lb 40 ft coach with a 450 Ism, same on ramp could do 60 mph when merging. Much more comfortable situation. Either coach could pull my toad up the mountains and do 70 on the straight though.

Mr&Mrs Duet · September 14, 2020

We just returned to Alabama from a trip to WA state. Ours is a 35' class A with a 300hp Cat C7. Our traveling weight is about 26K. We took I94/90 going to WA and I84/80 coming back across the rockies. Most of the time we cruised at 63/64mph. in the climbing sections it was 5th gear, approx 2000 rpm and 55mph. One short grade had us at about 50mph in 4th gear for a short section. We didn't have a toad. Next time we are towing the Jeep. I was very happy with our performance. As you can see we were not working the engine hard at all. I'm interested to see what the changes will be with the jeep being towed. What I really liked though, was the Engine brake and retarder on the descents. Nice control.

Kirk W · September 14, 2020

7 minutes ago, Mr&Mrs Duet said:

'm interested to see what the changes will be with the jeep being towed.

I did the same sort of thing with a gas powered class A and was surprised that towing the Honda CR-V only lowered mpg by about 1 mpg. I would suspect that you will see less than that.

Barbaraok · September 14, 2020

The only difference we found towing is that if you go into California, it is 55 mph if towing. We actually have a sweet spot at 58, so that's what we do as everyone else passes us by, including a lot of people towing. But with Texas plates, we don't want to anger any CA official. 😎