NicD

iTrader: (7)

OK, so I went to dyno my car today with a wideband O2 to do some tuning on my car. Its basically bolt ons with thunderracing 224 cam. I scaled my MAF by 115% to get my ltrims avging -4. All my attempts at leaning this out via the PE vs RPM table failed. I screwed with large changes, small changes, every change possible in between. Stock my PE vs RPM table was 1.24 across the board. I only changed things above 4800 RPM gradually to 1.10 at first. No changes at all. So the second time I changed everything from 4800 to 7000 to .95 (fill value). Well the changes are posted below in this link.
<img src="http://www.public.asu.edu/~nicolasd/nicdynowb1.jpg" alt=" - " />
WTF is going on here? Shouldn't those last changes (dynorun.004 BTW) have stayed like that across the whole rest of the run (5500 RPM and up)? All my attempts haven't worked at all. Anybody have input or could send me a file of what they have changed? I am starting to wonder if my PE vs RPM table isn't where LS1 edit thinks it is in my PCM or its changing it the wrong way. Help!

<small>[ May 11, 2002, 11:46 PM: Message edited by: Nic00Z28M6 ]</small>

AzzHauler

iTrader: (3)

Mine had a funky (worse than yours) a/f graph when I dynoed. I believe most of it is because I still have stock cats on it, messing the readings up. Do you have cats on?

NicD

iTrader: (7)

No. I have mac headers, off-road pipes, cutout. The A/F gauge was placed directly up into the cutout quite a ways. None of my changes made any effects.

SSpeed

My PE Rpm value was 1.2403 across the board. Stock 1999 LS1 SS computer. Different now of course. All down like 94% then from 4800-7200 decending by additional 2% increments.

I wonder if the single value PE is normal?

NicD

iTrader: (7)

Yes, stock my PE values were 1.24xx across the board. I have any autotap logs from 1 of the runs and all looks normal with avg 27 deg of timing, no knock retard, O2s were reading fairly rich around .935 (especially according to the wideband).

Thank you SSpeed, I was wondering how much others were changing their PE values, but your ~94% answer helps a lot. Just wondering on a sidenote, did you scale your MAF table or injectors and did you tune with a wideband dyno?

SSpeed

Correction I scaled the PE rpm map by 97% across then did the 2% additional incriments from 4800-7200. Meaning 4800 x 98%, 5200 x 96%, 5600 x 94% and so on. Only reason I did this is because my car had a tendency to richen up from 4800rpms after holding a flat curve under 4800.

Injector Flow rates were scaled back 92% to give me around -4 Ltrims as positive Ltrims consequently add more fuel proportionally to the Ltrim value at WOT, while negative Ltrims will add no further enrichment.

At first I tuned with ATAP leaning the car out until I ran into knock retard and detonation (91 Octane) but I kept going until I got to 80% scaling and I started seeing .600mv fluctuations so I said screw it and bumped it up 5% a left it as is until I dynoed the car. Went and dynoed and the WB o2 showed a 14.7:1 AF ratio yet no knock retard or audible pinging. HMM! So for saftey's sake I rescaled the car as is which has me at around a 12.5:1 Af ratio graudually leaning to a near 13:1 at 6800rpms. Any richer and I start losing timing. HMM!

Only way to know exactly what your car likes for tuning is to get it on a dyno with a wideband to figure out what works for you.

NicD

iTrader: (7)

ttt, can somebody tell me how much they have changed their PE vs RPM table (percentage changes?) or send me their file?

ChrisB

I don't think your PE vs RPM should be 1.24 across the board? Is your program stock?.

Your results are strange - do you have a copy of the log runs for the dynos?

Chris

Smoke_ur_5.0

iTrader: (2)

Did anyone touch your PCM ever? Where did you get the cam put in at?

NicD

iTrader: (7)

Nobody has touched the PCM but me.

NicD

iTrader: (7)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SSpeed:
<strong>Injector Flow rates were scaled back 92% to give me around -4 Ltrims as positive Ltrims consequently add more fuel proportionally to the Ltrim value at WOT, while negative Ltrims will add no further enrichment.
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Just wondering why did you change your injector flow rates instead of scaling your MAF table likewise. Did you change injectors?