Super C advice

[eem1958]

I'm in the process of researching super c 's for our next rv. I have some questions and need an unbiased assessment. I'm looking at a 12000 tow and 360hp package rv and question whether I'm going to have issues traveling across the mtns and rolling hills. Im pulling a car trailer loaded at 8-10k lbs and wondering if I was going to be disappointed in the 360hp package. I'm believe just because it has a 10k or 12k hitch attached doesn't necessarily mean the rv will perform well.

Not sure if I need more hp and torque on a heavier class chassis. My concern going to something heavier is the rv needs to be able to tow, and also functional for pleasure traveling. Even with pleasure traveling, will have secondary vehicle on dolly or small open trailer. Thanks for any advice or experiences.

[CC38EL]

My 2002 RV had a Cummins ISC and I've towed 5600lbs with a 350hp 1080lb torque setup with an Allison 3060 transmission over mountains. My scale weight was 22000lbs before the tow.

It worked great in Indiana. Rolling hills would cause the cruise control to down shift, but nothing too bad. Mountains were a different issue. I always felt a little underpowered going up 5-7% grades, but only got to really slow speeds in the badlands of SD and mountains of CO. I improved that quite a bit with a performance exhaust....but still wasn't flying along.

If you're looking at something like a Dynamax, you could get 350/1000 in a ISL which is 8.9L. I didn't see any option for a ISX or ISM. If I was looking to do what you're planning, I would definitely be looking at more torque which normally only comes with more HP.

[bhammond1980]

I had a 2007 Dynamax Grand Sport 380. It was powered by a Cat C7, 350 hp, transmission was the Allison 3000MH 6 speed. It had a GVW of 34,000 and a 20,000 lb hitch. We only towed our Jeep Wrangler 6,000 lbs at most. The coach worked great on flat or hilly roads but when it came to mountains it struggled. We would start a climb in the right lane with hazards on. It was fairly happy at about 30-45 mph, once you crested the top the exhaust brake was worthless. I was constantly on the brakes hoping not to overheat them, I can only imagine another 10,000 lbs of trailer.
We traded to a class 8 last year and it would have no problem with your car trailer and it would be much safer. I attached a picture of our old rig for your reference.

[BMGM37]

We have a 2018.5 Jayco Seneca which was the transition year for the new S2RV chassis with the 360hp/800torque Cummins. We commonly tow either a Jeep JKU at about 5k lbs or a 30’ cargo trailer with a sandrail, SxS, fuel and tools that is right at 10k and it doesn’t matter which combo, we get the same mileage and towing results with the 2 weights. I have no problem maintaining 45-50 on 7% grades if I can get a little run at it but usually traffic won’t allow and it will drop to 40-45 on so a 7% grade, 7 mile long hill. I am perfectly happy with that myself, others may not be...it just doesn’t bother me that it may take me 3-4 minutes longer to make it up a hill. On nice rolling hill freeways like we do going through Idaho, 65-70 is no problem at all. The exhaust brake is done through the VGT turbo and works great, just came back from a trip towing the big trailer down a 7-8% grade 7 miles long and probably only tapped the brakes twice, it’s very effective. Also the S2RV comes with the Allison 3000 and comes with a Eco and Performance mode which many don’t know about when they test drive. If you do, make sure you put it in “mode” which is the performance shift program....it is night and day between Eco and Mode.