Community Forums

charlibrown · 08-09-2012, 09:42 PM

Can anyone tell me how these engines compare? Looking at the 40' Holiday Rambler and the 40' Tiffin Phaeton QTH
Interested in which one has the most power and gas mileage.
Thanks!

Mr_D · 08-09-2012, 09:50 PM

I hope you never try to get "gas" mileage out of either one!!

historyljc · 08-10-2012, 09:16 AM

You might wish to look at the discussion on the FMCA site concerning these two engines: Cummins vs MaxxForce - FMCA Motorhome Forums

Gary RVRoamer · 08-10-2012, 09:27 AM

The standard engine in the Phaeton is the Cummins ISC 8.3L with 380 hp and 1050 lb-ft of torque. You can find further specs on the Cummins website. Make sure you refer to the specs for the RV/motorhome application rather than something else.

The Navistar MaxxForce 10 (9.3L) in the Holiday is 350 hp and 1150 lb-ft of torque.

So the Cummins has more horsepower but the torque peak on the Maxxforce is higher.

Personally, I'd go for the higher horsepower if that was the only difference between the two coaches. That's rarely the case, though. There are probably many other factors that are at least as important as the two engines.

R2Home · 08-10-2012, 09:39 AM

I too would like to know what the difference between these two engines is. The DW would like to upgrade our MH and I would like to have another Cummins engine. Is the Max force a 'V' or inline engine and what is the weight difference? At what RPM's do the engine run? While it may be true that there are other factors to consider when getting a MH, the engine is a 'major' factor for me.

John S. · 08-11-2012, 09:47 AM

Brett Wolfe wrote a great summary there. He is a fellow Foretravel owner and the head of the Cat forum and Cat engine group. I think that the Maxxforce engine does not require DEF fluid but I read that is changing. Also, the big issue is service. I am sure they all can service it but Cummins has a niche in Motorhomes and services them more often. I do not think I would let Maxxforce or Cummins be the deciding factor though in a 40 footer I would want a bigger engine period.... especially if you have slides. I had a ISC in a 34 foot none slide Foretravel then moved up to a 450 ISM and the difference was night and day. Cruising RPMs on the ISC was 1900 vs 1300. I think you are on the low end of the power to weight ration with either of these units. Not a huge issue if you do not drive much but if you do put on more than 10K miles you might have an easier time with a larger engine. I get 8 on the flat land and 7.5 over 4000 miles covering 1400 miles of mountain driving with teh ISM. It is not made any longer for road applications but the smaller 11L ISX is. But if you are going to be in the flat lands and are not goign to drive much I would not worry too much about engine size.

Gary RVRoamer · 08-11-2012, 10:21 AM

The Maxforce 10 is a 9.3L, inline 6 cylinder, just like the Cummins ISL (8.3L) and ISC (8.9L). Navistar doesn't give a lot of spec info on their website, but here's the link:

Motorhome - MaxxForce® 10 | MaxxForce

On the Navistar motorhome application page, they list the Maxxforce 10 as ranging from 310-405 hp and 1050-1250 lb-ft of torque, so make sure you know which configuration is in any motorhome you are considering to buy.

Motorhome Engines | MaxxForce

Steve Ownby · 08-11-2012, 11:48 AM

I currently own a Cummins and am very happy with it, but I would not hesitate to buy a motor home with a MF10 as the power. The MF10 is a full liter larger than the ISC and just under 1/2 liter larger than the ISL. Its power curve is lower than the Cummins so generally rpms are going to be lower depending of course on the final drive ratio used.

Divide the GVWR + toad weight by the horsepower on both coaches. The one with the fewer pounds per hp will be the better performer. This is really just an exercise however. The relative performance of both should be very close.

The chassis of these coaches are completely different and you should look at that and the quality of the house.

Cat320 · 08-11-2012, 02:11 PM

If the engine was the ONLY factor in making a decision, I'd go with the Cummins simply because there are so many more of them in MHs. However, if you like the coach with the Maxxforce 10 much better...get it, that engine will do all right.

pwf16129 · 08-11-2012, 08:23 PM

run from the max force engine we have several thousand and that is not a typo in our fleet they are not dependable hard to work on very expensive to repair we are running the max force 13 but they are basically the same engine.
egr valve failures,egr cooler failures,turbo problems,software issues,we are fighting this every day at times we have forty percent of our fleet down we bought them because they did not need def fluid and now they are looking to go back to Cummings engines.
we ran several thousand of these with really good success but our truck suppler dropped them in place of their max force engine.
just what we deal with on a daily basis