Midnightride
15+ Year Contributor
- 183
- 0
- Oct 4, 2006
-
Columbus,
Ohio
Ok so I recently installed the MAFT, also re-did the intercooler piping. Before the MAFT I was running 19 psi on the 14b. So I decided yesterday to take it and get it tuned on a dyno.
They didnt use the logger to tune, only based it of the A/F that they got from the back of the muffler. On the dyno sheet you will see a nice straight line there.
When I got there the most the car would hit was 13-15psi. So we raised it . Before at 19psi it ran fine and had a nice kick to it. now at 18psi as you can see it was pulling timing. The last run you see at 18psi we started to hear a pretty loud tapping sound coming from the head(valve cover area), so we let off. Car idles fine drives fine. My guess is its lifter tick, I've had it for a long time now, it comes and goes. I've never had the hood open during higher rpms so I'm not sure it thats normal or something else.
Either way, I was kind of disappointed with the results, with 550s, 190 pump, 14b ported and 3" turboback and a decent size FMIC I shouldnt be pulling timing that bad at only 18psi.
My guess is boost leak ? Since it was set at 19 before the install and now is at 15. Still dont explain the timing being pulled that hard though.
We did the pull in 2 in the automatic.
Any suggestion or what could be causing it would be greatly appreciated.
ps: also when driving around normally now, and watching the logger, the STFT and LTFT never balance out to both be 0 or adding them together to be 0. I thought that was the way to do it. I'm only asking cause under light acceleration it seem slow now, i was thinking maybe they were putting in to much or not enouph fuel.
mods are on a 2G automatic:
14b ported,exhaust manifold ported,o2 housing ported, 3" turboback w/ 3" hight flow cat,FMIC w/ hard piping,1G BOV crushed, 3" GM MAF w/MAFT, 3" K&N, 550s, 190 pump,SAFCII, running BPR 7ES.
They didnt use the logger to tune, only based it of the A/F that they got from the back of the muffler. On the dyno sheet you will see a nice straight line there.
When I got there the most the car would hit was 13-15psi. So we raised it . Before at 19psi it ran fine and had a nice kick to it. now at 18psi as you can see it was pulling timing. The last run you see at 18psi we started to hear a pretty loud tapping sound coming from the head(valve cover area), so we let off. Car idles fine drives fine. My guess is its lifter tick, I've had it for a long time now, it comes and goes. I've never had the hood open during higher rpms so I'm not sure it thats normal or something else.
Either way, I was kind of disappointed with the results, with 550s, 190 pump, 14b ported and 3" turboback and a decent size FMIC I shouldnt be pulling timing that bad at only 18psi.
My guess is boost leak ? Since it was set at 19 before the install and now is at 15. Still dont explain the timing being pulled that hard though.
We did the pull in 2 in the automatic.
Any suggestion or what could be causing it would be greatly appreciated.
ps: also when driving around normally now, and watching the logger, the STFT and LTFT never balance out to both be 0 or adding them together to be 0. I thought that was the way to do it. I'm only asking cause under light acceleration it seem slow now, i was thinking maybe they were putting in to much or not enouph fuel.
mods are on a 2G automatic:
14b ported,exhaust manifold ported,o2 housing ported, 3" turboback w/ 3" hight flow cat,FMIC w/ hard piping,1G BOV crushed, 3" GM MAF w/MAFT, 3" K&N, 550s, 190 pump,SAFCII, running BPR 7ES.
They based the tune of off using only the A/F. 
