tuning question

[bradofflorida]

I borrowed a scan tool yesterday and started tuning. Baseline with 100 octane unleaded was 15.5 lbs boost, 0 degrees retard and 900 MV. As we turned up the boost, the MV went down about 15 mv per pound. We stopped when boost was peaking at 20 and settling in at 19, with 840 MV, and a fraction of a second at 1 degree knock, then it went to 0 knock for the rest of the run. Should I back off the fuel pressure a little until gets to 780-800 mv? More MV means I am running a little rich, correct?

 

[fast eddie]

lean is faster but you need to keep using a scan tool just to make
sure your not getting any knock, at the track the car should go faster
Ed

 

[bradofflorida]

so you think I should just leave it where it is, a little rich for saftey?

 

[bruce]

Originally posted by bradofflorida
I borrowed a scan tool yesterday and started tuning. Baseline with 100 octane unleaded was 15.5 lbs boost, 0 degrees retard and 900 MV. As we turned up the boost, the MV went down about 15 mv per pound. We stopped when boost was peaking at 20 and settling in at 19, with 840 MV, and a fraction of a second at 1 degree knock, then it went to 0 knock for the rest of the run. Should I back off the fuel pressure a little until gets to 780-800 mv? More MV means I am running a little rich, correct?

The stock O2 is meant to be used in a switching type function, and not at all meant to be accurate in the way your using it. If you want to measure AFRs you need a Wide Band.

You're playing with having to replace headgaskets by guessing.

You find best performance by measuring performance, not by tuning to get a number.

 

[fast eddie]

buy a scanmaster the best investment you could make on these vehicles