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Old 08-19-2015, 10:58 PM   #1
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2005 Cummins ISL 400 or 2015 ISL 450???

We are considering upgrading to a 2015 Newmar Dutchstar with the 450hp ISL, however we are concerned about the new emission controls and using DEF. We are not sure if the cost and possible loss of torque is worth it compared to our 2005 400 hp ISL. any comments as to the newer diesels with added emissions?

We still love our current rig but maybe newer could be better...
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Old 08-20-2015, 08:45 AM   #2
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Quote:
Originally Posted by canes1 View Post
We are considering upgrading to a 2015 Newmar Dutchstar with the 450hp ISL, however we are concerned about the new emission controls and using DEF. We are not sure if the cost and possible loss of torque is worth it compared to our 2005 400 hp ISL. any comments as to the newer diesels with added emissions?

We still love our current rig but maybe newer could be better...
I went from a 1999 350 hp (40')to a 2009 425 hp, I do not have DEF on my '09, it isn't as powerful but it is also a 42' tag.

I personally wouldn't be overly concerned with the motor etc, you are looking at 10 year newer everything. I also loved my '99 and had no intention of getting rid of it, I had just spent over $10k with hardwood floors on 45, new toilet, valances, blinds, tv's etc and it caught on fire from my toad going down I-70. I loved my old coach, but I also love my new one and the newness of everything including technology and safety things like the side cameras, much better mirrors even though I had updated my mirrors on the '99.

Good luck with your decision.
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Old 08-20-2015, 02:30 PM   #3
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"canes1".....Last year we traded in our 2005 Monaco Diplomat 36' with a 400ISL for a 2014 Newmar Dutch Star with a 450ISL. The Diplomat only weighed 32K and I chipped the engine to 450 HP. It was a rocket. The 2014 Dutch Star weighs 5K more, taller coach (larger front nose) and a tag axle.

I believe the 400 ISL had 1200 pounds torque and the 450 has 1250 pounds of torque. The first time I climbed a grade, towing my Silverado, I almost cried. A grade I could pull at 55mph, I could now only do about 47 mph.

With all that said, I think the new 450 would run as well as the 400 if everything was equal, such as length, weight, wind resistance etc. We added a lot of weight, length and drag going to a 40' with a tag. I did find with this new motor is that it took about 12K to break in and it climbs the same with or without my truck attached. When climbing with the Monaco, there was a notable difference when towing without the truck.

I think if you buy something new in the same weight and size you won't notice a difference, but typically most go a little larger coach and lose some of that power. Overall the 450 ISL in my coach performs well. The 2106, 43' Dutch Star with the new 3K heavier frame and floor would probably push the limits of the 450 ISL. I think they will have to be looking at bumping future Dutch Star's to a small ISX.
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Old 08-20-2015, 02:32 PM   #4
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Originally Posted by canes1 View Post
We are considering upgrading to a 2015 Newmar Dutchstar with the 450hp ISL, however we are concerned about the new emission controls and using DEF. We are not sure if the cost and possible loss of torque is worth it compared to our 2005 400 hp ISL. any comments as to the newer diesels with added emissions?

We still love our current rig but maybe newer could be better...
DEF has been in use in European diesel on highway engines for some time now and has finial shown up on engines in the US. I know for a fact that the ISB 6.7L Cummins in the Ram pick-up trucks has better fuel economy and more torque output than the none DEF ISB 6.7L Cummins. The pre-DEF 6.7L Cummins engines that are emission compliant has had more emission issue than the DEF engines. This was due to the regeneration strategy and the requirements to use diesel fuel to burn off the soot in the Diesel Particulate Filter and more EGR requirements. With the use of DEF a lot of this strategy has changed and fuel mileage has improved.

I would not hesitate in buying a late model diesel engine that requires DEF.

Jim W.
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Old 08-20-2015, 02:42 PM   #5
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Keep your current MoHo....
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