Community Forums

djgaston · 10-02-2017, 09:25 AM

Has anybody here used a tuner to bump up their power a little bit on the ISX 525? I live in a really hilly area, lots of curves. While the Cummins has plenty of power on flatter ground or straighter roads, driving it around here basically has me impeding traffic on uphill stretches. Manual mode on the transmission helps a little. I don't think it needs much more power but anything would help. Bully Dog has a "big rig" site with a few tuners, I'm looking at the 46511 ECM tuner since I don't need gauges. They claim 75-100 hp and 12% better fuel economy. I have several vehicles with smaller Cummins engines and every one of them benefits greatly from being tuned (or in one case, "turned up" since my 8.3 is mechanical). I also found a site that sells a pigtail tuner and an EGR fooler, OTR Performance I believe was the site. Just looking for some opinions from folks who have tuned or otherwise modified their ISX to get it to run a little better. Fuel mileage isn't a huge concern, I am mostly looking for torque and a cleaner-running engine. Thanks in advance.

hypoxia · 10-03-2017, 07:43 AM

I would go to Rawze.com: Rawze's ISX Technical Discussion and more and see what they say. There are some excellent tuning guys there.

djgaston · 10-03-2017, 08:22 PM

Thank you; I will check them out.

I did order the Ugly Fix yesterday and will be installing that. I wasn't real excited about it just being a barometric fooler but my EGR system works fine, so the Ugly Fix should take care of me. If for some reason it doesn't work, for about twice the price I can get an actual EGR shut off module from OTR Performance. Right now I think I'll do the Ugly Fix and call Bully Dog to see what they say about their tuner on my motorhome. It's not listed for the specific application but it should work. Maybe I'll be the guinea pig. [emoji200]

C&SL · 10-04-2017, 04:08 PM

Be interesting to see if you will have any valve problem like the 600 & 650 do?
C&SL
05 Sig.

Steve Ownby · 10-04-2017, 04:16 PM

Quote:

Originally Posted by C&SL

Be interesting to see if you will have any valve problem like the 600 & 650 do?
C&SL
05 Sig.

Very good point. Since the OP shares the double overhead cam design of the 600-650hp levels that have proven to be fragile at those hp levels, I would hesitate to crank it up.

Randyman1 · 10-04-2017, 08:02 PM

I don’t know what you are expecting from your rig, but mine handles itself absolutely fine. I’ve never owned a coach that performs like this one does. I did add the Ugly Fix because of the cooler temps and cleaner burn they mention. I do feel it has upped the performance a little as well as increasing my fuel mileage by .3 to .5. I would hesitate to turn up the performance for fear of creating the problems mentioned on the 650 hp version of this motor. To each there own on how they feel their rig performs.

hypoxia · 10-04-2017, 08:40 PM

I have the Ugly Fix but haven't installed it as I can't reach that far. Perhaps someone has a Trunk Monkey I could borrow. Since I spend most of my time driving in big mountains I am also concerned about temperatures that can be exceeded once it is installed. If I get a Trunk Monkey to install it I think I will also install an exhaust temperature gauge to monitor it.

Randyman1 · 10-05-2017, 06:45 AM

Hypoxia, I installed my Ugly Fix about a year ago. I’ve been over the Rockies with it twice and haven’t had any temp issues. My understanding was it would allow the engine to operate cooler without the reburning of exhaust gasses. Also would allow the engine oil to remain a little cleaner. Don’t know if I have longer arms than you, but I was able to access mine from the rear opening. It was on the pass. side of the engine at about full arms length reach.

hypoxia · 10-05-2017, 07:52 AM

Randy, do you have a pyrometer on the exhaust manifold? If not there is no way to know if you have had a temp issue.

What are the boost pressures when hill climbing? Should never hit 40.

The information I read is that the Ugly Fix works but the exhaust manifold temperature needs to be monitored as it can go to 900+ which is way too high.

I can touch the module but can't reach far enough to change it. When I finally get it in I will also install a pyrometer.

Randyman1 · 10-05-2017, 09:25 AM

I don’t have a pyrometer, and my boost has appeared to stay the same at approx 38 max. so I can’t be overfueling to increase the temps. I don’t want to fry my engine either, but it was my understanding that there are some fail safe sensors already on this engine to keep you from frying it even under normal settings. I might be overestimating this, but I also have some mechanical savvy and don’t just drive the hell out of it with no regard either. I like the idea of keeping the EGR closed and have noticed that she doesn’t smoke as much keeping the exhaust tip cleaner on the outer edges than what it was before. All just my opinion, but it is something that after having I would not switch back from.

Mr_D · 10-05-2017, 09:37 AM

I have the 650, it's broken valves off twice in 47,000 miles. Now have 49,800 on it and it appears to be doing fine. The last rebuild was done with the newly issued parts that supposedly cure the problem. Just too bad that Cummins won't stand behind their poor design with a warranty like they did with the ISL wrist pin problem. I installed the Ugly Fix a couple thousand miles ago. Other than taking about 30 miles of driving to warm up and get good fuel mileage I haven't noticed anything good or bad.

djgaston · 10-05-2017, 10:34 AM

Are the 525 and the 600/650 the same engine except for tuning? Or are there internal differences?

vito.a · 10-05-2017, 12:25 PM

I installed the Ugly fix on my 07, but not yet on my 04. I have a new Ugly fix sitting there until I can get to it. The issue is finding the darn thing. Cummins wraps everything in black tape and then spray paints it red.

Mr_D · 10-05-2017, 12:48 PM

Quote:

Originally Posted by djgaston

Are the 525 and the 600/650 the same engine except for tuning? Or are there internal differences?

No idea, I think that's a question for Cummins to answer. I'm pretty sure there are major differences since the DOHC ISX uses one cam for the valves and the other for the injector triggering. The turbo would probably be different too.