Tuning help and questions

[BoostAddict]

I need some help with my S-AFC, please do not critize, as I've tried to find the answer but can't. I've got a 16g, 650cc injectors, 255lph fuel pump, B&M fuel pressure regulator, big greddy front mount, and all the supporting mods. I know I should have it tuned on a dyno or by a pocketlogger, but I don't have the money to do that yet, and need help on tuning it now. I'm trying to run right around 20psi of boost. I've found out that if I go any richer then -40% the car seems to like stutter, and not want to move really on hi throttle. My hi-throttle point is at 80%, and low is at 30%. It seems the leaner I go the better it runs, and the quuicker it is. As of right now its set all the way down to -50% leaner. The EGTs are right around 14 F, which I was told is safe. The car is pretty quick, but seems like it could be quicker. I have a boost leak tester comming in soon, as I was also told at one time that a boost leak could make you run leaner, if this is true I don't know. I just need to know if these settings are right. Also, on low throttle, the car only seems to run smoothly and good at -25%, which seems pretty lean also, but the a/f cycles from lean to rich, which I was also told is what its supposed to do. Any help would be nice. I don't really know much about fuel tuning yet, so please don't critize me for any wrong doing.

 

[kpt4321]

Do you have a logger? If you do not, then you need to get one.

What is the FPR set at?

-50% is way too lean.

....Kyle T.

 

[deusxmachina]

With all of that stuff replaced, including the front-mount, there's no point in playing with AFC settings until at least that boost leak test is done. Nowadays, I consider it to be completely foolish to run 20psi on pump gas without a logger. You simply can't easily tell what you're doing, and you risk blowing things up. At least hook a voltmeter up to the air/fuel in the meantime to see what your O2 voltages are.

 

[BoostAddict]

I found out the problem, it was a boost leak, it was actually a pretty bad one. Before I fixed it, with my boost turned all the way up it only wanted to run 20psi, then drop down to 17psi. But after I fixed it on the same setting it was running 29psi! Not good for your engine, but diffently was the fastest thing u ever felt till I looked down at my boost guage and saw that. But now I'm running around -30% leaner. It still doesn't like to go much richer, but it diffently is driving a lot better, and is a lot faster. I also took out the side honeycombs and flushed back thje screw which helped.