PDI Stage I C15 issue and ??

**JW Trucking** · 03.16.2012

Ok so maybe someone on the forum has run into this or can help me out I sent a message to Mr Haney but I know he is busy and we got in a hurry on a job that came up so I had to buy the kit from a local guy and get these trucks out on the road asap so I had them bring the computor over and do the tune.

Anyways we have 2 PDI ISX tunes WoW amazing no issues problems or anything as of yet MPG is har d to gauge yet but it's better how much yet I am not 100% sure but the drivers love it and we are going to give a fuel bonus if they can keep the throttle backed out and pull some MPG's on this job. EGT's don't seem to be an issue at all with the drivers even with 105500 so far nothing above 850-900 even on the longer pulls.

But my ?? is the C15 pulls 105500lbs STAGE 1 PDI tune my Dad is the OO and it's got 359000 miles on it so with the higher miles he drives it very easy. MPG's are in line with the stock 475 tune on the same haul route ect so nothing great but again we are learning how to drive the tune so it may take a few weeks to get the MPG's up. Power is great but here is the problem.
If he takes off and just before a hill we have to slow down for a corner or truck ect thus he does have to push it a little for the hill 3/4 throttle or so. Pyro's are in line 800 he backs out to 3/4 throttle but at 60psi of boost we get a air leak sound but you only hear it through the air cleaners and the boost gauge starts to bounce all over the place sounds like a pshhhh pshhhhh. We back off get back on it again and sometimes it goes away but it sounds like the wastegate can't make up it's mine and is opening up then slamming closed again and again very fast.

Called PDI and 3D's they say this is a problem and could take our turbo out as they have had this happen before but don't give us any direction in how to fix this issue other than "drive around it'. Well Ok at 80,000lbs I could see that but at 105500 it's not as easy as one would think. If you keep it at 50psi it runs like a champ no issues at all but sometimes we have to push it in that 3/4 throttle for a bit and that is when it will go to 60psi once we get some speed up a guy can back it down to 50psi and it will run all day long without any problems at that boost level.

To me it sounds all the world of a wastegate actuator on the turbo fluttering as you hear it through the air cleaners. No leaks on the charge tube side of things that I can see at all checked it out pretty good also checked the wastegate actuator lines all good no leaks ect..

Any Ideas??

Also I'm not a huge fan of the 60psi don't get me wrong the power is great but even at 50psi the thing pulls like a champ and just motors along so much better than my stock 475 it just acts like the motor is not even working when you back out of it and I am behind him still wide open on the poor old 475 tune.

Another Idea I had is we have a Electronic boost control system off our Race Car we use to control the boost off the waste gate. What would happen if I cut the boost back to 50psi?? Would it mess with the fueling on the PDI tune?? Or is the PDI tune sense boost and adjust fuel as to the current boost like our race cars??

Just curious if that was the case I would enter in 50psi and just run it at that and let the waste gate cut the boost back a touch.

Sorry for the long post.

**DL550CAT** · 03.16.2012

I had some issues with mine before I had a tune. Mine would act like it was blowing the wastegae open and boost would drop and take awhile to come back up. What I did to cure that was I took a 1/4" bolt cut the head off and the threads off so that you have about a 1/2" of shank. Then I drilled a very small hole through it lenthwise. I dont remember the size of the drill bit. It was a letter bit and it was tiny. I then installed it in the boost line. What that seems to do is act as a restrictor so the boost does not blow the wastegate open. It allows the waste gate to open at normal pressure though.

**pullingtrucker** · 03.16.2012

I'm guessing you are actually experiencing turbo surge with your PDI tuned ACERT. This happens when the turbos are pushing more boost pressure than the engine can use. The compressed air has to go somewhere, so it backfeeds back past the turbo(s) and through the air cleaners. This is a very bad situation if it happens alot. The turbo(s) could and will come apart if it happens enough. The only other direct fit turbo for a ACERT is a 625 HP ACERT turbo, but no one is really sure if this turbo solves the problem. I suggest you back off the motor a little and try to keep the boost lower. I understand the weight you haul and the reservations you have about getting the weight moving. But, I haul a tad less than you and I have learned to keep the boost down to avoid the turbo surge. DO NOT UNHOOK THE WASTE GATE...on a ACERT this will lead to a turbo failure with even higher boost pressures and even more turbo surge.

**JW Trucking** · 03.16.2012

Ok you may be right pullingtrucker.

If that is the case why can't a guy use a system so the wastegate dumps some of the boost. We will have a driver in it every now and again and if it was not a problem to cut the boost back I would sure rather do that with our weights it does this so much that I don't see any way we can back out of it anymore than he allready is. Same thing many high performance cars and diesel pickups use. They also make manual ones as well here is a link of an example of a manual one http://www.turbosmartusa.com/product/in-cabin

Just throwing it out there as an idea if I can open the wastegate at 50psi I think I could make the problem go away for good plus help the life of the turbo's out.

**pullingtrucker** · 03.16.2012

I don't think having the wastegate open sooner is going to totally solve your problem. The ACERTs move a lot of air and the wastegate is pretty small. I know what you are trying to do with the in cab controller and for less money you could buy a aftermarket adjustable wastegate and just set it to open earlier. You have to remember though that the ACERT wastegate is already set to open at about 31 PSI if I remember right. So you probably won't get much result like I stated earlier. There are others on here that are better with turbo and boost issues...so hopefully they will chime in.

In hind sight you should of just contacted and waited for Mr Haney on your original purchase. He has the most experience with high HP CATs than anyone on here and could of sold you the right tune/parts the first time. I hope he will chime in and help.

**Mr. Haney** · 03.16.2012

I sent you an email.

This does sound like turbo surge. Something else is going on to create this. I don't have anybody experiencing this problem with a PDI Stage 1 tune, whether it's a 475 Hp or 550 Hp tune. I actually have a few customers with Stage 2 tunes that aren't having any issues similar to this. I've also seen a number of Acerts with PDI tunes at the dyno contests that don't generate turbo surge while producing 780 Hp to the tires at 1400 RPM.

Is your father pulling the engine RPM down low when this happens? Can he drop a gear to raise RPM and not have this happen?

**JW Trucking** · 03.16.2012

"In hind sight you should of just contacted and waited for Mr Haney on your original purchase"

You are 100% right there.

Ok got the reply sent a reply back as well maybe it's a good idea to keep it on the forum incase others have this issue.

No we are running it in the 1400 to 1500 range on the hills never below or above as we try not to spin the C15 more than the 1500 mark. 18 speed so we can keep the RPM's just right. Also to add it's got new air filters and we do have dual outside cans they are the smaller 13inch but I don't think that would be an issue. Also took the old style mufflers off and put the free flow mufflers on so that should have let it breath much better as well. It does not have the PDI manifold like our ISX ones have just thought I would throw that out there.

Just a thought what would happen if the wastegate was not opening at all?? If say the rubber in the wastegate was bad or had a crack and the wastegate was staying clossed the whole time??

**superhauler** · 03.16.2012

i had the same surge problem it kept getting worse. then one day it stopped lost some pulling power. found out my cac had a crack in it that had been growing over a 7 month period. the crack would expand and contract depending on the pressure. causing the whooshing sound. just found it tuesday. just so happens i was going by st george ut. stopped and put a new duralite on and no more whooshing sound. had a cac from detroit rad. wont make that mistake again! the crack measured 16 inches long right up the side of the right side.

**JW Trucking** · 03.16.2012

superhauler did your boost bounce much or just starting going down??

Ours will make the needle bounce all over when it does this.

**superhauler** · 03.17.2012

Originally Posted by JW Trucking

superhauler did your boost bounce much or just starting going down??

Ours will make the needle bounce all over when it does this.

yep sure did. needle vibrates all the time. but real bad at top boost. it still vibrates a little after the new cac but not as bad. i also have another issue with a turbo leaking boost around the clamp that holds on the cold housing on the top turbo. thanks to cats quality reman junk! make sure you dont have a leak on any of the clamps on this setup. the way i check is idle up to 1500 rpm this will produce about 2 lbs of boost. then squirt with soapy water or windex, then look for the bubbles. even squirt the boots even a little bubble can be a bigger leak at high boost. that will be your leak. cant really do this with the cac. have someone pressure test it with some air and see if the pressure leaks off via a guage. most radiator shops can do this without taking it out of truck. mine was cracked bad enough that you could see it. i could put my hand on it and move the crack in and out.