DP Torque/HP

[TriMoot]

Glad I found this thread as we are also looking and have similar needs vs cash. However I need 40 or more feet and need to be educated on horses and torque.

I’m aware of the 1hp per 100lb rule so have been mostly looking at 400Hp rigs, but of course there’s the wrist pin issue with those Cummins engines 2005 to 2007, so that’s been a challenge.

Since we’ll be traveling from corner to corner (Spokane Wa to Melbourne Beach Fl) each year a comfortable ride is important. I’m in no hurry but reliable and quiet is important when climbing hills.

It seems like the OP has had his questions answered but I’m still listening, so any knowledge you have about these beasts and their engines, I’m ready.

[gruelens]

Respectfully, I am confused with all this torque and horse power concern.



Does "RV" mean Recreational Vehicle or Racing Vehicle?

[texasrs]

Trimoot


I think the wrist pin issue was with the ISL in 2006, with engine serial numbers ranging from 46543077 TO 46603939.

Look for a coach with an ISM 500.

[Meames1]

Originally Posted by texasrs

JCUSSEN


Certainly agree with your recommendation of an ISM Cummins. They are practically bullet-proof.

My dream, a pre egr 500 ISM in my 40' 30,000 gvr single slide.

[n2zon]

Originally Posted by texasrs

Trimoot


I think the wrist pin issue was with the ISL in 2006, with engine serial numbers ranging from 46543077 TO 46603939.

Look for a coach with an ISM 500.

Right, only part of one year. The link to the information has been posted by several people and is not hard to find.

[Alpine36]

Power to weight ratio is key. I agree with 1hp per 100lbs.
Our 36' DP is rated at 330hp/990ft lb, but moderately loaded only comes in at just under 27,000. Add a 3,400 lb toad, were right about 30k. Performance is respectable, fuel mileage surprisingly good too, almost 10mpg, but don't expect to win any drag races with any DP. I've never heard any DP owner say they wish they had less power, although I have heard a few with huge power say they wish they got better mpg.
Go figure.

[Mr_D]

I have one of the problematic ISX 650/1950's in my 52,000# '09 Country Coach. Average is 7.7 mpg over 64,000 miles. But 3 rebuilds in that time at an out of pocket cost of $53,000 is not good. However, once rebuilt with the latest parts there have been no further failures in the dozen or so I know of.

[Roadmiester]

I have a pre emission ISM500. Been a good engine so far. They have an "ugly fix" for most Cummin's that will boost your power. From what I understand the ISM500 can be pushed pretty close to 600 hp with the ugly fix. That 500 is pushing a 45 ft., tag axle with a Ford Explorer toad. Loaded up we are right around 48,000 pounds. Besides steep grades there are long stretches of slight inclines that can also slow you down. Also headwinds can slow ya down. Nice to have the hp and torque without the need to keep your foot smashed to the floor to maintain speed.

2009 Dynasty Regal IV
ISM 500, Allison MH4000

[00zx6r]

I wouldn't bargain with anything less than ISC 350/1050. There are some Alpine Coach, Travel Supreme Monaco, H/R, Foretravel 38' with side mount rad out there with 400/1200.
I just picked up 1999 H/R Navigator equipped with ISM 450/1450/4000 two week ago from Texas and drove home in Ca 1400 miles without hiccup.
To me you can change/upgrade the interior but it very difficult to change/upgrade the engine and trans if you feel it under powered.

[Ivylog]

The “UgFix” is not going to add 100 HP to a 500 HP engine...doubt it’ll ad 5. It does increase mpg slightly because you are not adding burt gasses to the intake air.

The Cummins ISL/ ALLISON 3000 (1250 max torque) is a excellent combination. The ISL 400, 425, 450 HP are all 1200 to 1250 torque... more a way of designating EGR, DPF, and DPF plus DEF. The 8.9 ISL is a stroked 8.3 ISC, also a good engine. Yes, I would not buy ISL in the wrist pin #s having talked to a owner that had a big hole in the side of his ISL at 53K miles. Took 3 years and a lawyer to get Cummins to help some on a new engine.

In the 500+ HP league, I would only want a Cummins ISM or a DD60 engine. I didn’t learn of the ISX #6 intake valve issue before I bought a rig with a 06 ISX 525. If it was a 650 HP, I’d be putting the newest head on it ($25,000).

[TriMoot]

So here’s a quick question....if I’m shopping on RVTRADER or RVT.COM and all it shows is “400HP Cummins” how do I go about getting specifics? Better yet, how do I only look for the good ones?

[stuccosteve]

Originally Posted by Ivylog

The “UgFix” is not going to add 100 HP to a 500 HP engine...doubt it’ll ad 5. It does increase mpg slightly because you are not adding burt gasses to the intake.

In the 500+ HP league, I would only want a Cummins ISM or a DD60 engine. I didn’t learn of the ISX #6 intake valve issue before I bought a rig with a 06 ISX 525. If it was a 650 HP, I’d be putting the newest head on it ($25,000).

The truth, the DD60 is legendary and the ISM is earning its worth. Juicing the big blocks is tricky, you need to have proprietary program access and some smart aftermarket writers to design “supporting software” which can tell the ECU to Modify timing, fueling and turbo boost on some Engines. It’s all in the type of engine management system you have.

I don’t advocate trying to dial up a Cummins 500 ISM to 900 hp and 2500 Tq like some guys get in the small block Cummins, what that would do to your MPG is frightening.

[jimmy braden]

Originally Posted by TriMoot

So here’s a quick question....if I’m shopping on RVTRADER or RVT.COM and all it shows is “400HP Cummins” how do I go about getting specifics? Better yet, how do I only look for the good ones?

LOL
my friend, you just entered the world of alice & wonderland.

nothing is what you expect..

Find a coach with a floor plan you like and send pics.

Tell the seller you want to see it in person. and fi they dont accept that then keep looking.

[jcussen]

Originally Posted by Onthehunt49

Thanks to everyone for all the replies.
From what I am seeing. About all the rigs 2003 to 2008 in my budget, have 660 to 860 lbs of torque. From 300 to 350 hp.

40 ft would be too long for my rv parking pad at my house. Gate to gate is 41 ft.
I would not be able to gat around rig.

Many ISC 350 will have 1050 ft/lbs of torque. If you can find a high line coach in your price range, could have an ISL, ISM, Series 60 or a Cat C12 or C13, some will give you 400+ hp and 1200+ ft/lbs of torque, but you will have to look for these coaches, especially under 40 ft. I know Foretravel made 34, 36 and some 38 ft tags in those years with the ISL or ISM engine.
The 36 ft Foretravels with the ISM had a great power to weight ratio with 450 hp, 1450 ft/lbs torque at 27500 lbs.