2010 Camaro SS twin turbo, leaning out at 3800RPM

[raven3800t]

Ok so this is kind of a long story so bear with me here. I have a customer who just bought a 2010 Camaro SS that has been twin turbo'd and apparently tuned to make just over 600whp. Now normally that would be no big deal but he bought it out of Colorado and brought it back to Canada with him. For the record the car was built and tuned in Colorado at an elevation of 4500ft asl and then brought back here where we are right on the ocean (my shop is about 250ft asl). In addition to that elevation change we have a difference in fuel at only 91 octane as opposed to 93 in Colorado.

My customer decided to drive the car the 3000 miles to bring it home. He had it home for a day before it blew up. Since he doesn't know much about modified cars he brought it to his local GM dealership and they changed him to replace two bent rods and a piston. I have the rods here at my shop and they are definitely bent. After GM rebuilt the engine he started looking for a local tuner, he found me and here we are now.

When I first got the car I figured it wouldn't be much work to tune it out so that it would be safe in our area but of course when I think something should be easy it's not. :P So after looking through the file that was in the car I noticed a few things that were not right. First off was the PE table had been raped, commanding 10.2 in some spots. PE engagement was a little low and some other small things. First thing I did was set the PE table correctly to command an A/F of 11.3 (was going to target this till I got a handle on the car and then lean it out from there). I also pulled a few degrees of timing just to make sure it would be safe. On the first pull to 3500rpm the MAF transfer fuction was way off, even with the computer commanding 11.3, in reality I was seeing about 12.8 - 13 on both widebands (one in the car and the dyno's wide band). After a few edits fuel was pretty good up to 3500, I then did a pull to 4000rpm and this is where I ran into problems. The car will lean out at 3700 to 12.2 before I pulled out of the throttle. The MAF sensor is only at about 7500hz when it leans out so we are no where near maxing the sensor out. Even if I add fuel in those cells to the max that I can (4000) I still get the same results. At this point I did another run logging commanded fuel pressure and actual fuel pressure and commanded is at 58psi and stayes but the actual pressure starts out at 58psi and drops to about 51psi at 3800rpm. From the reading I have done this seems normal for these cars.

At this point I got a hold of the shop that actually built the car and they are telling me that there was nothing done to the factory fuel system other than 60# injectors. The engine itself is completely stock. From all the research I have done the factory fuel pump should be good to about 525-575rwhp depending on who you ask. The car as it sits is making 341rwhp @3800rpm and 443rwtq @3800 @ 7psi so in theory I still should have some head room on the factory pump but it doesn't appear that way. The company that built the car said they made just over 600rwhp at 8 - 10 psi but I am finding that a little hard to believe at this point considering everything that happened and what I have seen in the file they built for the car. I am not sure if the elevation change would have that much effect.

The other thing that I noticed is that the fuel pump setting have been left untouched. I tried raising the high flow value to 70psi but that did nothing on the scanner, it would not switch to the high commanded flow value. Other strange things are all the VE equation tables are zero'd out and the car has been forced into open loop and had the decel disabled as well. I will be honest here and say that I have not done much with the newer camaro's other than bolt-ons. This is the first one I have played with in a twin turbo application. I have done twin turbo'd vettes without any troubles but this new FPCM stuff is new to me. I have been reading about guys running the msd boost a pump, or running twin pumps such as the cts-v but again I am not sure why we are leaning out at only 340rwhp when we should be able to make more than that on the factory setup.

Here is a copy of the file that came loaded in the car. You will notice the things wrong that I have already talked about. Is there any other suggestions out there as to what could be causing this?

Thanks,
James

[blazenstyle01]

Without being able to actually see the tune right now i would say look at the injector flow rate table and make sure it has the proper values in it.

[DSteck]

I'll try to help out later tonight. That setup should be a joke. Run it pure MAF, and use closed loop.

Don't bother trying to get more out of the FPCM. There's still a mechanical regulator in the fuel system that'll limit rail pressure to 58psi.

[raven3800t]

I'll try to help out later tonight. That setup should be a joke. Run it pure MAF, and use closed loop.

Don't bother trying to get more out of the FPCM. There's still a mechanical regulator in the fuel system that'll limit rail pressure to 58psi.

Thats what I figured as well. I was thinking of starting again from a scratch file and go from there so I'm not trying to find someone else's mistakes but I figured I would throw it up here first to see if it just something stupid I'm missing.

[raven3800t]

yeah that is the file that came with the car so I didn't build it. I did change those settings though and no difference. The car is going into PE just fine, it's still commanding 11.3 when it starts to lean out right till I pull out of the throttle.

[DSteck]

The PE settings in the file are how they should be set for a boosted car. You don't want to rely on throttle, you want to rely on boost to trip PE.

Try to find out exactly what kind of injectors it has. Whoever set up the injector data in there is an idiot. All in all, that file is pretty poor.

Give this a shot. I only changed a few things because I really don't feel like redoing that thing from scratch in it's entirety.