tuning question regarding MAF
Thread Starter
Joined: Nov 2001
Posts: 3,406
Likes: 2
From: Tallahassee, Fl
tuning question regarding MAF i LONG LONG time ago i ported the maf on my car and my car really liked, gained 6 hp and 4 ftlbs on back to back dynos and my a/f has always been as close to perfect as possible even before tuning
when i was cam only, untuned the a/f was a flat 12.8-12.9 and i was getting about 27-28 degrees of timing with no KR. when we tuned the car we leveled the a/f out to about 13.0 and bumped the timing up to 29-30 degrees and the car ran great (didnt gain crap for power but oh well).
well now after adding the heads, i had a chance to dyno with wideband and atap the car. the a/f was lean in the midrange, than leveled out slightly lean, and finally ended around 12.8 (ill post the graph on the bottom of this). the thing wasnt getting full timing either. there was also no KR.
i was wondering if using a stock, unported maf, or a descreened unported maf, would possibly fix the slightly lean condition or the timing condition, or if it is something that will be fixed through tuning only and i should leave the maf alone.
what do you think???
i have also since added a much better exhaust to the car, not sure what that does to a/f or timing, just thought i should add that.
heres the dyno
heres the atap
thanks
ryan
when i was cam only, untuned the a/f was a flat 12.8-12.9 and i was getting about 27-28 degrees of timing with no KR. when we tuned the car we leveled the a/f out to about 13.0 and bumped the timing up to 29-30 degrees and the car ran great (didnt gain crap for power but oh well).
well now after adding the heads, i had a chance to dyno with wideband and atap the car. the a/f was lean in the midrange, than leveled out slightly lean, and finally ended around 12.8 (ill post the graph on the bottom of this). the thing wasnt getting full timing either. there was also no KR.
i was wondering if using a stock, unported maf, or a descreened unported maf, would possibly fix the slightly lean condition or the timing condition, or if it is something that will be fixed through tuning only and i should leave the maf alone.
what do you think???
i have also since added a much better exhaust to the car, not sure what that does to a/f or timing, just thought i should add that.
heres the dyno
heres the atap
thanks
ryan
Staging Lane
Joined: Nov 2003
Posts: 57
Likes: 0
From: Arizona
Your additional mods could have definitly leaned you out. But never the less with the new mods you should definitly retune. Your timing does come from your MAF and RPM (gm/cyl by RPM). So you are flowing differently now than you were prior to the installation of the heads hence the different timing. Most DIY tuners would probably agree that tuning with an aftermarket MAF is a PITA. IMO I would put the stock MAF back on and retune. I would not change my MAF unless it was maxed out at over 12000 hz. I have 420 rwhp n/a and mine hits up to 11,000 hz in the high rpm so I have a ways to go. 
