Horsepower Needed for a 34 Foot Diesel Pusher Towing a Jetta

[WannaTravel9]

My wife an I are wanting to move up from a 5th wheel to a motorhome. We'd be towing a Jetta that comes in around 3100 lbs.

We're hoping to find an older unit, around 34 foot, diesel pusher. Question is, how much horsepower do we really need to be able to tow the car, and keep it at about 60 mph. Pretty much everything around ( within a 4 hour drive) is 5.9 Cummins, 275 to 300 horsepower. I just don't want to be doing 35 to 40 going up hill.

 

[Larry N.]

My wife an I are wanting to move up from a 5th wheel to a motorhome. We'd be towing a Jetta that comes in around 3100 lbs.

We're hoping to find an older unit, around 34 foot, diesel pusher. Question is, how much horsepower do we really need to be able to tow the car, and keep it at about 60 mph. Pretty much everything around ( within a 4 hour drive) is 5.9 Cummins, 275 to 300 horsepower. I just don't want to be doing 35 to 40 going up hill.

Better get used to it. Motorhomes are not race cars, and they NEED all the gears they have, especially going up hill. Shallow hills can, in many (not all) motorhomes be climbed without too much speed loss, but ANY class A or class C will lose speed on steeper hills, how much speed loss depending on the steepness AND the length of the climb. I had a 525 HP DP (Diesel Pusher) that was often under 35 mph part way up some of the mountain highways (after starting at 65 mph), perhaps even a tad lower if it went too long. I had another 360 HP DP that climbed a bit better, but it was lighter, too. Ones that do very much better are scarce as hen's teeth.

So if uphill speed is your thing you probably should stick with a high powered, turbocharged pickup with a 5th wheel because motorhomes tend to be about 100 lbs/horsepower.

 

[CharlesinGA]

Get a Cummins and stay away from Max Force (International)

 

[Brad Buchanan]

My wife an I are wanting to move up from a 5th wheel to a motorhome. We'd be towing a Jetta that comes in around 3100 lbs.

We're hoping to find an older unit, around 34 foot, diesel pusher. Question is, how much horsepower do we really need to be able to tow the car, and keep it at about 60 mph. Pretty much everything around ( within a 4 hour drive) is 5.9 Cummins, 275 to 300 horsepower. I just don't want to be doing 35 to 40 going up hill.

We have a Horizon that has a 350hp Cummins in it. We tow a '23 Wrangler and we run from the Canadian border to Florida each winter.

There are a few climbs through the mountains and the slowest we had was about 45mph. We weigh just over 30000 with the Jeep hooked up and when not towing I feel the difference mainly when accelerating.

It should be noted that this rig is a 2004 with a 8.3 liter engine and has no def or dpf. Apparently the emission stuff really cuts down on the performance.

I was talking to a fellow in Florida who has a Prevost bus with a 600hp motor and he told me that it didn't pull much better than his prior rig which was pre def and dpf and had a 400 hp motor.

 

[weighit]

For a while we had a 34 ft tiffin RED with 340 hp pulling a Cadillac SRX SUV. It did pretty well, but you are going to slow down climbing so you have to be prepared.

 

[Gary RV_Wizard]

For a long time the RV industry unofficial design standard for motorhome horsepower was 1 hp per 100 lbs of GVWR.. That meat a 30,000 lb GVWR coach got 300 hp. Improvements in diesel performance in the last decade have improved that somewhat and now it is common to see more like 1 hp per 85 lbs. Even the improved ratio isn't great performance - your car or SUV is probably 4x that HP:weight ratio. Even the little 4 cylinder engine in my compact size Hyundai Tucson SUV manages 1:20. So your big Class A coach isn't going to accelerate quickly from a stop or rave past other vehicles. And it will almost sure slow to 35-45 mph on a long 4-6% grade.

 

[rjshiflet]

I know you're looking for a diesel, but just for "horsepower" sake we had a Georgetown Class A with a Ford V-10 engine and it had a reported 362 HP. I don't know where you live, but if you're familiar with the beautiful "Texas Hill Country" (and they are hills with LONG climbs, not really "mountains") and we struggled at times. And that beast of an engine would sometimes downshift into who-knows-what gear and it would roar like a herd of elephants to maintain 40 mph on some of the extended hill climbs.

 

[John From Detroit]

I know you're looking for a diesel, but just for "horsepower" sake we had a Georgetown Class A with a Ford V-10 engine and it had a reported 362 HP. I don't know where you live, but if you're familiar with the beautiful "Texas Hill Country" (and they are hills with LONG climbs, not really "mountains") and we struggled at times. And that beast of an engine would sometimes downshift into who-knows-what gear and it would roar like a herd of elephants to maintain 40 mph on some of the extended hill climbs.

I had the Chevy 8.1 I think it was rated around 330 and only twice did it ever struggle.
Once I had to "Drop" the towed and drive the two independently (Made it however)
And the other time I made it but ye old Allison was in LOW gear by the time I hit the peak.

It never failed to get over the hill however even in mountains.

When the engine was killed by an accident (Oil cooler line got cut) the mechanic who replaced it went out and bought a Silverado with the same engine.. He was impressed by it.

 

[Utclmjmpr]

It doesn't mater how much horsepower you have when climbing,,you will surely get stuck behind a slow truck and be traveling his speed.. I have always maintained that speed when climbing is NOT a priority,, getting to the top with everything working properly IS..>>>Dan

 

[Trav_Lr]

Horsepower is for high speed and maintaining velocity. High torque allows a vehicle to accelerate quickly from a stop, climb hills efficiently, and tow heavy loads. Change your focus to higher engine torque if your concern is towing and hill climbing. The 275 HP 5.9 Cummins in a 34ft DP is a workhorse, but will struggle badly on hills when towing.

 

[Gary RV_Wizard]

The Cummins "B" engine (originally 5.9L & now 6.7L) is the lower powered RV diesel, usually configured to provide 300 or 340 hp and 850 lb-ft of torque. Decent power for coaches up to about 30,000 lbs when coupled to an Allison 3000 6-speed (avoid the smaller 2400 & 2500 Allisons if power is a priority). Better, though is the Cummins L9 (1250 lb-ft & 450-500 hp) or the X15 (1650 lb-ft & 525-565 hp).

The big Allison 3000 & 4000 trannys are both 6-speeds with the two top gears being overdrives for cruising economy. When you hit a relatively steep grade, both trannys soon downshift to 4th where they can deliver the engine's peak power, but that also limits speed.

 

[Brad Buchanan]

I know you're looking for a diesel, but just for "horsepower" sake we had a Georgetown Class A with a Ford V-10 engine and it had a reported 362 HP. I don't know where you live, but if you're familiar with the beautiful "Texas Hill Country" (and they are hills with LONG climbs, not really "mountains") and we struggled at times. And that beast of an engine would sometimes downshift into who-knows-what gear and it would roar like a herd of elephants to maintain 40 mph on some of the extended hill climbs.

lol!

 

[Adventurous Traveler]

When I bought my 36' DP, the 6.7 Cummins, formerly the 5.9, was rated at 300 HP and 660# of torque. It weighed in at 22K +, with a GVW of 30K.

Shortly after buying the RV, I took it to a local Cummins Dealer, and for $351, they reprogrammed the computer to 360 HP and 800# of torque. This made a tremendous difference in the "performance", if you can associate that word with an RV. I towed a Kia on a dolly. Perhaps the biggest difference was in fuel economy. In 2022, I averaged 10.97 mpg on just under 13K miles. Half of those miles were a trip from WNY State to Yellowstone, Napa, and Yosemite NPs, going over the Rockies on I-70 eastbound and I-80 westbound for the return.

The biggest victory for the small Cummins was Old Priest Road <YouTube It> close to Yosemite. Our Garmin RV GPS took us on this very dangerous, twisty, switchbacked 19% graded road. I never thought we'd crest the rise. However, the engine and Allison tranny performed beyond expectations, going from 1st gear to 2nd, trying 3rd, and backing down to 2nd, and before we knew it, we were out of danger.