This is my first post on rv.net. I plan to purchase a motorhome soon. I have it narrowed down to 2 units. Both are 40' long but one has a 330 hp Cummins and the other a 400 hp. Of course that has to make a difference but my question to those of you that have a 330 hp Cummins, is the 330 sufficient to climb the mountains out west? Also, anyone out there have a 400 that once had a 300 hp?
Both will do fine. Compare and contrast the overall weight as used, the gear ratios, number of gears in the transmission. It's possible the unit with the 330 hp engine is lighter... Power comes from fuel, so the higher HP engine will use more fuel when it's actually producing the higher HP - the vast majority of the time both engines will be producing far less power than their ultimate limit. The old rule of thumb was 1 hp per 100 lbs of unit weight, and both are probably well over that lower limit...
I have never owned a MH, but I am a retired truck driver having driven > 3,000,000 miles. All other things equal, without question go with the 400hp. You can always throttle back the 400 when not needed, but once the 330 is at the max it's done for.
msg1951 wrote: This is my first post on rv.net. I plan to purchase a motorhome soon. I have it narrowed down to 2 units. Both are 40' long but one has a 330 hp Cummins and the other a 400 hp. Of course that has to make a difference but my question to those of you that have a 330 hp Cummins, is the 330 sufficient to climb the mountains out west? Also, anyone out there have a 400 that once had a 300 hp?
Thanks,
Steve
Hello, Welcome to the forum.
I'm just curious. This is your Second Post. You asked the same question two days ago. Did you not like the answers you received the first time you asked the question?
Hello, Welcome to the forum. Sorry, I said that when you first posted.
I'm curious too. This is your Second Post. You asked the same question two days ago. Did you not like the answers I gave you the first time you asked the question?
Thanks for including more info on which engine so I'm fairly sure you are looking at a ISC and a ISL engine. The ISC should have 1000 ft lbs of torque and the ISL can put out 1300 but is limited to only 1200 because of the 3000 Allison tranny.
Assuming the coach with the 330 weighs 7,000 lbs less than the one with the ISL there will be no difference in performance.
This post is my opinion (free advice). It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
WeBeFulltimers wrote: All other things equal, without question go with the 400hp. You can always throttle back the 400 when not needed, but once the 330 is at the max it's done for.
The best answer to your question.....A Cummins 260 ISB will get you to the top of any mountain out west. The question is, how much time do you want to take to get there. For a 40' coach, I would take the 400 everyday and yes, I have had a 38' with a 300, so I can compare....
Bob & Betsy(FishNFanatic) - USN Aviation Ret'd '78 & LEO Ret'd '03 & "Oath Keeper Forever" '05 HR Endeavor 40PRQ, 400 Cummins-Pulling our '11 Silverado LT, Ex Cab 6.2L NHT 4x4, w/2010 Rzr or 01 V Star in back. Where the wheels are stopped today
Cause I hate to run an engine at full HP ,,, It won't last as long!
There may be some arguments for "bigger is better", but not wanting to run a HD diesel engine at full HP is NOT a reasonable one.
Remember, these engines are used to pulling 2-3 times that weight at high speed all day long, year after year in OTR trucks. You will NOT wear one out. Could you neglect one to death-- yes. Can you wear it out-- VERY unlikely.
This applies to Caterpillar, Cummins, Detroit Diesel.......
Unlike gasoline engines which make peak HP at a very high (and unsustainable RPM for long periods of time) the engine under discussion makes peak HP at 2400 RPM and can run at that for a VERY long time. Larger diesels achieve peak HP at even lower RPM.
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