Performance Module for Cummins ISL 400

[Tom Curnow]

I am doing some consulting for a company that manufactures Performance Modules for cars, trucks and RVs I am going to install one of thier units on my Cummins ISL 400, they offer several levels up to 90HP improvement. I will be using a G-Tech instrument to reoord stock performance and after installation preformance.

There a couple of units on the market that look inferior to this unit.

Has anybody had any experience with such a product on the ISL 400, I have a Allison 3000MH transmission, hope the increase does not have a negative impact

Thanks for any input

Ps: Big rig users have reported a 10-15% increase MPG also ( not using all the performance avail)

[Tom Curnow]

I am doing some consulting for a company that manufactures Performance Modules for cars, trucks and RVs I am going to install one of thier units on my Cummins ISL 400, they offer several levels up to 90HP improvement. I will be using a G-Tech instrument to reoord stock performance and after installation preformance.

There a couple of units on the market that look inferior to this unit.

Has anybody had any experience with such a product on the ISL 400, I have a Allison 3000MH transmission, hope the increase does not have a negative impact

Thanks for any input

Ps: Big rig users have reported a 10-15% increase MPG also ( not using all the performance avail)

[ua40j]

Tom, I have no experience with adding any kind of performance module. What I do know is that any change to the computer setup on either the Cummins or the Allison is logged into the Engine Control Module or Transmission Control Module if one of those devices is put on the J1708 or J1939 bus. Some devices are after the module and are not detected. The reason I know this is because I once worked for Cummins on the team that created that software. Cummins for sure, and Allison most likely, have detection abilities in their modules. They have to in order to avoid getting into losing battles over warranty costs.

The main limitation on increasing HP or torque on a RV is the torque limit of the transmission. I don't remember what the limit is on the Allison MH3000, but coupled with the ISL 400, it has to be close to maximum. Be wary of over torque on the transmission as you increase HP.

The other thing to consider is warranty. If my engine and transmission were still under warranty, I'd be leary about add-ons. I'm not a lawyer, but I do know that I blew #6 cylinder a few years back in our ISC350 and the bill was $8000....and we were nowhere near our home. It was under warranty and they covered it. But I would hate to find myself in a situation involving thousands of dollars for a repair and end up in a warranty battle while my coach sits unmoveable.

If I'm out of warranty, then it's not an issue as to who is going to pay for any repairs.

I believe most places that offer these devices tell their customers that these things will not void warranties. And that may be true. But normally, the point of discovery is at the time of repair.

Just my .02 worth. Let us know how it goes.

[Sixpack98]

Jim makes an excellent point regarding the 3000MH transmission. Its input rating is 450 HP and 1250 ft lbs torque. Later models of the ISL 400 is up to 425+ HP and 1250 ft lbs torque. The ISL on our '06 HR endeavor is 400 hp and 1200 torque. So, the ISL is just about at the limits of the Allison 3000MH and most motorhomes equipped with the ISL are also equipped with the 3000MH transmission. Even if my ISL and 3000MH were out of warranty I'm not sure I would install a performance module.

[Tom Curnow]

Thanks for the input

I stopped by Cummins Cal Pacific here in LA, a very savvy tech there ( who is also a drag racer so he knows performace stuff) said if I used the 40-50 HP gain I should not see any problems as the torque rating should only increase 50#s or so, he sugested installing a exh gas temp guage as well as a boost guage,he said keep an eye on the guages when really working the unit hard and make sure they do not get out of sight, he is going to give me the max numbers from a book he has at home, with that practice,if the temp or PSI raises just back off to normal ratings and no harm will be done, the damage occurs with prolonged abuse, ( just like over eating lol) thanks again will post the test results when I get the project under way

[Harry B]

Tom,

Is it possible to limit the performance gains to stock engine ratings (400HP/1200lbs torque) and just realize fuel consumption improvement? Now that might be of interest. Diesel prices are not going to stay as low as they are these days

Look forward to seeing your results. Specially from a diesel fuel economy improvement perspective.

[Tom Curnow]

Harry, I am still waiting for more defined info, but as I understand it, if you do not lean on the throttle too much you will gain MPG, the product I am working with has been suppling big rigs for some time and thier concern is MPG primarly but power is a plus for grades. I checked with Cummins and my engine has a recall open for a recaliberation of the ECU. I want to get that done and get a base line before I make any mods, I suspect this is going to take some time, will update this post as I see what happens in the real world

[avfordguy]

I have a 5.9L 275hp that has been "chipped" to 325hp, power is great, economy is still good, 38ft monaco 29k gvw chassis towing and full load still gets 10mpg.....yah I am happy, southern california with all the long grades ( I live near the "grapevine" and go to vegas ( baker grade) all the time. Last trip to vegas averaged 10.2 and that was at 65 mph, both ways with WOT on all the grades