The turbo boost stacking the */C would make sense of it. How far is your pulley wheel shaved?

Edit...You beat me to it Jeff.......

After thinking about it more, I really think he'* running out of MAF. This is from my car, the green line, second graph from the top I'm near the max of 10,500 on my MAF. And that'* without a turbo. Does your tech2 give you a graph like this?

The max MAF is 11,500Hz. It is a LS1 MAF. It is good for 500whp. I am only at about 10,100Hz. it was reading 318g/* at 5413rpm and the next value was -325g/* at 5600. It went -320g/*, -318g/*, then jumped to 326g/* at 6150 right before it hit the rev limiter. I have never seen this, but I talked to someone who said it'* reversion. I could move the MAF away from the t.b. a little, or use a real boost controller to eliminate the boost spike, or I might try opening the bypass valve at like 5200-5300 with a RPM activated switch. I don;t know, it' still runs great. The a/f did not go lean, it only showed 1deg KR from 5200-5500. I am only running 12-13deg timing right now.

Where is the MAF located? 12-13 degrees of timing seems a bit low. I try to shoot for 15-18 degrees of timing. What tuning software are you using? Is that the tech2? I have no clue how that works, wish I had one though.

Maf is right in front of the t.b. 12-12deg is SAFE, you may not know, but I blew this thing up twice! :(

I don't want to kill it again. I have used a DHP Powertuner since 2004, but I am begrudginly making the switch to an HPTuner.

I am in the very early stages of tuning. i am set on an 11.5:1 a/f ratio and the aforementioned safe timing. I want to be able to drive this onthe street with varying fuel qualities and conditions without fear of detonation. What will be a better tune is when I go to the track and run 100-101 octane. I'll lean it out and bump the timing. The stated goal from the beginning was 500whp on 20psi or less. I should be able to do that given the current state of tune with only another 5psi, esp if I can do it with just a little more from the turbo.

This set up is kind of new to me, so I'm going to try and help best I can. I use HPT, so does billboost, and purplehaizer. So if you do make the switch you will have some help. Correct me if I'm wrong, but shouldn't the MAF be before the turbo? I seem to remember seeing a grand prix with a turbo/supercharger setup. and that was MAF, throttle body, turbo, supercharger. I'm not exactly sure how your'* is, can't quite tell from the picture. Perhaps I just need more info on your setup.

I chose to blow thru the maf. I personally think it'* the way to go. Plus, plumbing would be a bitch if I tried to put it in front of the turbo, I'd have no room for the a.f.

My fuel trims are 10% pretty much across the board at 11.5:1. I am skewing the fuel inj flow rate b/c i was having problems in the beginning. The first step is to get the inj flow rate correct and have the fuel trims near zero. then I'll start to balance the front and rear banks. Then I'll maybe lean it out to about 11.8-12.0 max and try a little more timing. I have not even installed the ice chest in the trunk yet, so all the i/c is is ambient temp.

I'm pretty good tuning, been doing this for over 6 years. Built and tuned the turbo GA, it makes 370whp on 17psi... from only 2.0 liters!

that should be "-10%" fuel trims.

-10 is pulling a fair amount of fuel. I don't think that'* your problem though. Any chance you can post a image of a scan, something like this.


I find this helps me find problems

Ya, as I said the inj sizing is skewed. I think I have in there 55# in flow rate, but I am running 65# injectors. I forgot it was this way until i was comparing and changing my file to a base file in HPT. I am -15% in the low fuel trim tables and -10% in the higher tables. I can change that in the Powertuner and reset the fuel trim. I might get better gas mileage, too, since the pcm won't be working as hard.