Community Forums

jermars · 02-18-2025, 06:27 PM

I happen to read on RV Life an advertisement for Diesel Modules selling performance modules for numerous diesel engines. Has anyone tried one of these modules that is advertised as a plug & play unit that is downstream from your ECM that will not cancel out any warranty because it leaves no trace.
I have a 2015 DS on a Freightliner chassis, I'd be interested in your thoughts.

Thank you

d23haynes57 · 02-18-2025, 06:44 PM

From the physical point of view a lot can be done to increase the performance and even the efficiency of Diesel engines. As delivered for RVs Power is often set for marketing such as the 8.9L can be anywhere from 380 to 450 HP. You want more power, buy the next level coach up. More important is the tuning to reduce emissions. Of a priority for Diesels is reducing the formation on NOx. To do this inject timing, quantity, compression ratios, turbo boost and of course EGR is used to reduce these emissions. Thes also can reduce power and efficiency.
From the compliance end these "tuning" add Ons are in fact considered tampering. VW was amongst the first to get caught with this. Other manufacturers including Cummins got caught, and some manufacturers, suppliers of aftermarket parts are getting caught and getting fined or prosecuted. It is likely that at some point individuals will be next. Some states already have enforcement programs in place. We deal with restrictions for catalytic converter replacements. Fines are steep. Would you really want to go there?

WILDEBILL308 · 02-18-2025, 07:09 PM

Quote:

Originally Posted by jermars

I happen to read on RV Life an advertisement for Diesel Modules selling performance modules for numerous diesel engines. Has anyone tried one of these modules that is advertised as a plug & play unit that is downstream from your ECM that will not cancel out any warranty because it leaves no trace.
I have a 2015 DS on a Freightliner chassis, I'd be interested in your thoughts.

Thank you

If you do decide to do something like that I would install a quality EGT gage. The proper place for the probe is before the turbo. Many of the changes can drive up EGT (exhaust gas temperatures) dramatically leading to outher problems like turbo failure or burnt exhaust valves. Yes I was a bad boy when I had a ISB. Banks engineering website has some good information.
Bill

BPeas · 02-18-2025, 07:14 PM

With a 450 in the DS, you need to check the max torque and horsepower ratings on the included transmission.

d23haynes57 · 02-18-2025, 08:15 PM

500 HP changes the trans to the 4000 and also the drive shaft and rear axle.

jermars · 02-19-2025, 06:57 AM

Thanks for all of the replies! Basically, my DS performs well 90% of the time. Many of our trips always seem to include some long pulls that draw the coach down quite a bit, and if you get caught up behind some really slow moving semi's, forget it.
After 76 years patience has never been one of my better virtues, I'll continue to live with this situation since you folks have given your opinions on the subject and try to sit back and just enjoy the ride.
Again, Thank you!

Jerry

Tony Ramirez · 02-19-2025, 07:15 AM

Even w ALL the HP in the world, sometimes it's still gonna work out you get caught behind a slow semi.

Like Miagi said, "PATIENCE GRASSHOPPER." Or is that the DW, "JUST BE PATIENT" yelling at me? One of those.

d23haynes57 · 02-19-2025, 07:28 AM

Reaching the top of the hill at a lower speed makes it safer to go down the other side? Using the throttle you're making a purchase. Using the brakes, exhaust or service on the way down, you're burning off that purchase. Coasting downhill without any braking is a free ride.

oldenavy · 02-19-2025, 07:45 AM

I used to have a tuner (I think that’s what you mean by “modules”) in my RAM pickup truck. It allowed me to select five different programs of varying torque and power levels and gave me the ability to read and reset trouble codes. Mine came from these guys: https://duramaxtuner.com/diesel-tuni...ins-tuner.html
They claim they keep you legal and specify that they don’t work on vehicles with defeated emission systems. They have products for all pickup trucks and HD vehicles as well. The biggest benefit I got was adjusting the shift points because my trans was tuned for fuel economy and was constantly lugging the engine. The tuner also had a Wi-Fi app for the phone that would let you see all sorts of data out of the ECM, kinda like the Bluefire does. When I sold my truck, I put the factory tune back into the ECM and removed my tuner device.

If your DS is already at 450HP, I think that’s the highest rating Cummins allows on the 8.9L. Go any higher and you’re inviting all sorts of expensive stuff to break, as mentioned above.

Dutch Star Don · 02-19-2025, 04:13 PM

On my 2005 Monaco Diplomat with the 400 ISL, I installed a DIGIcr diesel tuner. It plugged inline and changed fuel distribution and didn't affect the ECM. It had about 16 settings. When set on setting 9, it added 52 HP to the engine. I also changed out the engine fan which returned 25HP. My 05 Diplomat only weighed 32K, but those changes made it a ROCKET.

With that said, I doubt you'll find any "modules" that will connect to your 450ISL (L9) that will provide any additional power. There may be modules for an older ISB, but not your current ISL.

Bears Dad · 02-20-2025, 06:14 PM

pdidiesel.com Every Newell out the door has one. I can tell the difference on my DS.

Tizbad · 02-21-2025, 07:18 AM

More power equals more fuel. More fuel means more btu’s. More btu’s could cause overheating. Your cooling system is designed for the original power package.

Thanks,
Stu

d23haynes57 · 02-21-2025, 08:15 AM

Quote:

Originally Posted by Tizbad

More power equals more fuel. More fuel means more btu’s. More btu’s could cause overheating. Your cooling system is designed for the original power package.

Thanks,
Stu

Overheating does not always show up in the cooling system temperature. More BTUs; or higher temperatures can raise the temp of internal components such as the pistons to valves. More power comes from more torque, which comes from increased pressure in the combustion chambers and top of pistons. More torque; more stress. Also, the increased pressure and temperature increase the production of NOx. Changing shift points to prevent downshifting also have an effect on NOX production. Many tunes can be emissions tampering.

Unplanned Tourist · 02-21-2025, 08:29 AM

Quote:

Originally Posted by jermars

Thanks for all of the replies! Basically, my DS performs well 90% of the time. Many of our trips always seem to include some long pulls that draw the coach down quite a bit, and if you get caught up behind some really slow moving semi's, forget it.
After 76 years patience has never been one of my better virtues, I'll continue to live with this situation since you folks have given your opinions on the subject and try to sit back and just enjoy the ride.
Again, Thank you!

Jerry

Good choice.