Size per HP

DanTheRVMan wrote:
Understanding Performance

If Speed up hill concerns you read the above link.

If having the wife happy when parked listen to the wife.

Thanks for the link - good reading.

Our 42' dynasty has the ISL 400 which is a very good combination of power and fuel mileage. Just as important in my opinion is the "jake brake" which was part of our iso package. I find the "jake brake" is a must have as I can descend most any mountains on the east coast without touching the service brakes.

I have a Cummins ISM in 450. Had a 350 isc before. Best thing about theISM is that it is the smallest heavy duty engine. The isc is medium duty. We are not going to wear them out but i hope to try. The best thing is that the bigger engines have so much more torque and turn much slower. I run about 1350 rpms at 62 mph in sixth gear and under 1400 at 65. It is not getting up the hill faster but getting up the hill at all. Also, the bigger engine gave me a bigger transmission so my retarder is much stronger too.

Does it matter to you if you are doing in the low 40s on steep mountain grades? That is the real question you need to ask yourself. Those who are satisfied with lower HP have decided that is OK with them. That may very well be a good decision, especially if the % time you are actually pulling those hills is small compared to the rest of your driving. On the other hand, if that will frustrate you, then lean more toward the higher HP. How much traffic do you expect to contend with? That is another factor in determining what your needs are.

For me personally, traffic is my biggest concern. Driving through Chicago, the on ramps can be tight clover leaf, and abruptly dump you into traffic moving 65 mph or higher. That is where the higher HP really makes a difference for me. That and driving 2 lane roads in Indiana.

Thank you all, Your comments are truly appreciated.

Of course you want adequate HP/torque to move the mass that you choose. But: you won't spend nearly as much time on any hill as you do with the slides out and drink in your hand while parked. Put floor plan on top of the list and be ready to give up a few HP if necessary.

Our 40' is 370 Cummins ISL - have had it for 9 years - and we love the western mountain driving. We have had no feeling of too little power. Good luck in your search!

My experience has been the bigger the coach the bigger the engine should be. I know my fuel mileage has improved with the bigger engine. My 40' Dynasty had a 300HP Cummins. While the B engine was bullet proof, it was a dog up hills and struggled with the weight. The 45' coach with the 525HP Cummins cruises without straining up hills etc. Better fuel mileage too...for a 40' coach, IMHO, minimum should be 400HP....Dennis

Understanding Performance

If Speed up hill concerns you read the above link.

If having the wife happy when parked listen to the wife.

I had a 40' Diplomat with 3 slides and a 330 HP Cummins and went everywhere with it. The engine was fine. I pulled a truck and had a motorcycle mounted on a lift on the back. I've got more HP and torque now but the MH weighs more.