Autotap results with supercharger

[Superv6bird]

I installed a powerdyne supercharger last summer. Took it to the track and ran a 14.9.

Here is the link to that post which includes more details about that run:

http://www.camarov6.com/cgi-bin/ulti...&f=10&t=000661

I have since bought autotap to try and discover what is causing my poor track times. Here is the results. This shows 2nd and some of 3rd gear. Can someone help me understand what this means:

(RPM)(Timing Advance)(O2b1s1)(02b1s2)(KR)
3755 -16.5 900 945 1.7
3866 -16.5 915 945 1.5
3948 -17 900 945 1.3
4033 -17 895 945 1.2
4109 17.5 895 945 1.1
4174 -18 905 945 1
4255 -18 900 945 .8
4340 -18.5 910 945 .7
4413 -18.5 905 945 .6
4473 -19 910 945 .4
4535 -19 895 945 .4
4615 -19.5 915 950 .2
4698 -19.5 905 945 .1
4766 -20 910 945 0
4909 -15.5 905 935 0
5003 -15.5 910 935 4.1
5061 -15.5 870 925 4
5100 -15 870 925 3.9
5201 -15 870 915 3.8
5243 -15.5 865 910 3.6
5328 -16 850 905 3.5
539 -13 860 905 5.9
5439 -13.5 840 900 5.6
5306 0 850 900 5.4
3495 -8.5 850 935 5.4
3713 -9 905 945 5.2
3734 -9.5 890 945 5.1
3745 -9.5 885 945 4.9
3788 -9.5 875 940 4.7
3810 -9.5 885 940 4.6
3832 -10 890 940 4.4
3844 -10 870 940 4.3
3855 -10.5 895 945 4.1
3912 -10.5 870 940 4
3936 -11 890 940 3.9
3996 -11.5 875 940 3.6
3984 -11.5 870 940 3.5
4033 -12 865 935 3.3
4058 -12.5 865 930 3.1
4096 -12.5 885 935 3
4109 -12.5 880 930 2.8
4122 13 870 925 2.7
4161 -13 885 930 2.5
4174 -13.5 860 925 2.5
4228 -13.5 860 925 2.3
4242 -14 860 920 2
4269 -14.5 870 920 1.8
4297 -14.5 880 920 1.8
4326 -14.5 880 915 1.6
4354 -15 865 915 1.5
4384 -15 860 910 1.2
4443 -15 870 910 1.1
4458 -15.5 875 910 1
4473 -15.5 860 910 .8
4535 -15.5 865 910 .4
4551 -16 865 905 .3
4631 -16 865 910 0

[ March 28, 2003: Message edited by: Superv6bird ]</p>

[DEE97GTP]

Looking to me that you are running lean for having a supercharger. You want your O2's around .92 if you are not intercooled and probably around .88 if you are intercooled. Running lean looks like it is causing KR(knock retard) and in turn in taking out alot of timing. That is causing a big power loss.

I would raise your fuel pressure or get a MAFT to help you out. You might log your injector pulse widths to see if they are maxed out. Anything over 22mS is pushing it.

DEE

[Superv6bird]

What numbers should I be seeing for timing advance?

[DEE97GTP]

For reference, I have a L67 engine with lower compression 8.5:1 and an eaton blower. I would tend to believe that you should be able to run at least 15 degrees of timing with a powerdyne, but I could be wrong. Stock GTP's have about 16-17 timing at WOT at 8psi. I have a new PCM and it will hit 18-19. That is at 13-14 psi, but I have some porting done. Normally I only run about 8 psi and I can even add another 2 degrees via the MAFT+. So I am running 20-21 degrees of timing at 8psi.

DEE

[Jason McCallister]

FWIW: You have in your chart, 02b1s2... I hope you were monitoring B2S1 instead of B1S2!? ;) If not, then you can throw out the B1S2 (post-cat) column! :(

[Superv6bird]

Your right I was looking at the wrong sensor. I made another autotap run today and looked at b2s1 instead. Still looks lean. Tried turning up the boost-a-pump and the results improved some. I am going to have to ditch the boost a pump and get the walbro in tank pump.My fuel pressure hit 84 psi today and it was still lean. FMU is working for sure, I just think the stock pump can't keep up.
I will still autotap again to measure injector pulse width's as DEE97GTP suggested.