MAFT tuning and injector help
08-09-2002, 07:02 PM
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MAFT tuning and injector help I've encountered an obstacle tuning my MAFT. I have a '02 Z28 M6 with the following mods: Hooker LT's, ORP, and exhaust; DirectFlo lid with K&N and ram air; ported MAF ends; NGK TR-5's with MSD wires. Here are my ATAP readings (averages) after all of the mods, before MAFT:
Cells 0-5, 21 (no load) 14.7 / 15.11
Cells 17-20 (idle) 9.3 / 10.5
Cells 6-14 (part throttle) 9.5 / 8.0
Cells 22 & 15 (WOT) .904 / .875 25.5 max timing with 0 knock retard
I installed the MAFT, and based on the above data I adjusted the base to 10% rich. Here are my ATAP averages:
Cells 0-5, 21 (no load) 4.9 / 4.1
Cells 17-20 (idle) 2.3 / -0.5
Cells 6-14 (part throttle) 6.0 / 5.6
Cells 22 & 15 (WOT) .930 / .916 22.5 max timing with 0 knock retard
The L-trims look much better, but the O2's are rich at WOT and I'm getting less timing advance. The car feels slower.
Where do I go from here? Am I losing timing and performance because the PCM is reading more load? How do I cure this......bigger injectors and lean with the MAFT? Any help would be greatly appreciated!
Cells 0-5, 21 (no load) 14.7 / 15.11
Cells 17-20 (idle) 9.3 / 10.5
Cells 6-14 (part throttle) 9.5 / 8.0
Cells 22 & 15 (WOT) .904 / .875 25.5 max timing with 0 knock retard
I installed the MAFT, and based on the above data I adjusted the base to 10% rich. Here are my ATAP averages:
Cells 0-5, 21 (no load) 4.9 / 4.1
Cells 17-20 (idle) 2.3 / -0.5
Cells 6-14 (part throttle) 6.0 / 5.6
Cells 22 & 15 (WOT) .930 / .916 22.5 max timing with 0 knock retard
The L-trims look much better, but the O2's are rich at WOT and I'm getting less timing advance. The car feels slower.
Where do I go from here? Am I losing timing and performance because the PCM is reading more load? How do I cure this......bigger injectors and lean with the MAFT? Any help would be greatly appreciated!
08-10-2002, 12:17 AM
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Re: MAFT tuning and injector help That's not correct. 10% rich, or #3 on my MAFT, richens the mixture by 10%. 10% lean, or "E", on my MAFT leans the mixture by 10%. Look at the Atap data that I posted. Pre-MAFT #'s are roughly 10% leaner than after installing the MAFT and setting it to 10% rich. Setting my MAFT to 10% lean, as you suggested, gives me idle Ltrims around +20 (lean)......which is 10% leaner than my pre-MAFT figures.
08-12-2002, 02:53 PM
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Re: MAFT tuning and injector help Hey Mike....thanks again for sending the MAFT to Downey for me!
I've been gathering injector PW data for the past few days. I'm hitting 80% duty cycle around 4800 rpm. By 5600 I'm at 94%, and by 6000 I'm at 100%. There is still plenty of capacity in the cruising range. I'm getting good #'s and performance with the MAFT set at 15% rich on the base and 4% lean WOT...but I'm still not getting full advance at WOT (only 22.5 vs. 25.5 before the MAFT). There is no knock retard. Is my injector duty cycle ok, or should I upgrade to SVO 30 lb injectors and lean the base setting?
I've been gathering injector PW data for the past few days. I'm hitting 80% duty cycle around 4800 rpm. By 5600 I'm at 94%, and by 6000 I'm at 100%. There is still plenty of capacity in the cruising range. I'm getting good #'s and performance with the MAFT set at 15% rich on the base and 4% lean WOT...but I'm still not getting full advance at WOT (only 22.5 vs. 25.5 before the MAFT). There is no knock retard. Is my injector duty cycle ok, or should I upgrade to SVO 30 lb injectors and lean the base setting?
