I finally have the datalogger recording of my car for a drag race at the drag strip last month. It's O2 sensor voltage versus RPM with the car leaned out a bit with a SAFC. By the way, this run was a 15.87 second run.

The SAFC was set to (at high throttle):
rpm correction
1000 0
2000 -1
3000 -2
4000 -3
5000 -3
5500 -4
6000 -4
7000 -5

The data is a bit weird. In 1st and 2nd gear the O2 voltage steadily climbs from 0.74V at 4000 rpms in 1st to 0.88 to 0.90 volts at 7000 rpms in 2nd, then is does what I would expect it to do once it's in 3rd, it levels out at a consistant value (about 0.90 to 0.92 V).

Now, I have two runs from LAST year with no SAFC which show the O2 voltage steady in all three gears (in between shifts, of course), and the lowest the voltage goes in last year's data (it was in 3rd gear at it's lowest value) is 0.94V. This would leave me to believe leaning the SAFC out a bit is doing what it's supposed to do, the O2 voltage went from 0.96-0.94 (no SAFC) to 0.92-0.90 (SAFC leaned out) in 3dr gear.

I have the data file saved as a .txt file so anyone can look at it if they wish, just let me know and I'll e-mail it to you (I know some people have been waiting for it). I only have this one run right now, another run is going to be e-mailed to me where I didn't lean the SAFC out as agressively.

I didn't get a baseline run this year when I was taking the data a month ago, the only baseline runs I have are from last year. I can send those as well, if anyone is interested. Hopefully tomorrow when I go racing I can get a baseline run AND leaned out runs all in the same day.

Todd Scungio
98 RS
15.803 @ 86.48 MPH

I'd like to see em. Shoot them to the e-mail in my sig. Base runs would ne good too. Since my next "stage" of mods in cludes the S-AFC I want all the data I can get for tuning her. Thanks

"To strive to seek to find... and not to yield."
Michael J. Kulaga e-mail: Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga Website: http://highlander.dsmpower.com/

Injen CAI w/ K&N Breather Filters, AFX UDP, 55mm TB, GS-T Muffler, FU/RU/RL STBs, Front NRG Susp. Motor Mount Ins., Red Silicone Hose Kit, 8.5mm Magnecor Wires, Bosch Rapidfire Plugs, TSW Blade 17x7.5, Bridgestone Potenza RE730 215/45ZR-17

And in my Room: Rear disc brake conversion kit, SS Brake Lines, Intake manifold 4 porting, Rear Motor Mount Ins. RRE FL Tie Bar(Well Almost), Slver Cadmium Plated KVR Cross Drilled Rotors and KVR Carbon Fiber Kevlar Pads (Well Almost)

My question to you is, what were your EGTs? It's possible that you an still be running too rich even though your O2s are saying .90-.92V. You can have those voltages and still only be running about 1350EGT.

Also, what were your knock sums? If they were zero, I applaud your tuning. That would be incredible.

Another big difference, now that you have an AFC is the octane of the fuel you use. You should be able to start using 92+ octane and lean it out more. But I wouldn't do that until you get an EGT installed and trust it.

SEA97GS - 15.785@88.20MPH
NW.DSM.ORG
HotShot Headers-Custom 2.5" exhaust-MSD 8.5mm plug wires-NGK Plugs-Nitto NT555R Drag Radials on RX-7 wheels-Eibach ProKit Springs-Tokico shocks-front upper STB

I don't have a thermocouple for EGT, that should be installed down the road. The values I'm using for the SAFC are LESS (-5 when it could be a -6 or -7) than what was suggested to me on this board by someone who did check EGT with their SAFC (I forget who it was)

I think I am running too rich at 0.90-0.92V, I am trying to aim for 0.88V, I think that will give about the 12.6 to 1 air/fuel ratio I'm looking for.

I was using 93 octane when I did that run. I did not check knock values, (that's an excellent suggestion!) but my guess would be the car isn't pulling the timing and I'm not seeing knock at 0.90V, since I didn't "feel" a loss of power and it was a 15.87 @ 86.4 mph run. I'll try to remember that tomorrow and check knock values as well if I get a chance to use a datalogger.

Todd Scungio
98 RS
15.803 @ 86.48 MPH