power enrichment RPM is the main fuel adjustment, right? most of the numbers vary from 1.05-1.2? Is that a multiplier, or an adder?? ie, if I want to lean the car some, do I use a lower number than 1.05, or do I use a number lower thank 1.0, or do I use a negative number???

Thanks!

Dave

<small>[ September 30, 2002, 06:03 PM: Message edited by: Dave F ]</small>

 

bigger number is richer, lower is leaner

but you just select the cells you want to add more fuel in and mult them by a number bigger than 100% to richen

mult by 99% and down to lean them out
i believe thats the right way...

but you should get on wideband when playing with that! U can make small adjustments for fuel to the MAF(same formula)

just log your ltrims for 10 mins at part throttle. If they are positive then you can tune the MAF to get the -3 and that should put things in wack <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

could care less about part throttle. Just want to make sure I don't go too lean on the first attempt, and I will be using a wide band.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Dave F:
<strong>could care less about part throttle....</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If your LTFT's, at part throttle, are positive, meaning they are correcting for a lean condition. When you got to WOT, they will lock at the positive value and make your WOT runs richer.

That's why they say tune part-throttle first.

 

My car, obviously isn't a WC Z06, but here are the numbers that I started with on the dyno, to ensure that I wasn't running too rich. I will give the corresponding PE % and the resulting a/f ratio.

I have a fully modded Heads and Cam vehicle. My MAF curve is adjusted 7% up to eliminate positive LTerms.

Starting Curve. Richened at HP Peak for first run.
Resulting A/F 11.5 to 11.8

0.0000 400.00 800.00 1200.0 1600.0
1.2403 1.2403 1.2403 1.2403 1.2403

2000.0 2400.0 2800.0 3200.0 3600.0
1.2655 1.2723 1.2781 1.2849 1.3188

4000.0 4400.0 4800.0 5200.0 5600.0
1.3324 1.3421 1.3527 1.3634 1.3731

6000.0 6400.0 6800.0 7200.0
1.3731 1.3391 1.2955 1.2403

Changes made at 3200 and up. Reduced 3%
Resulting A/F: 12.8 dropping to 12.0 @ 5500

Changes made to entire PE curve. Reduced 1%
Resulting A/F: 12.8 dropping to 12.2 @ 5500

Changes made at 4800. Reduced 1.5%
Resulting A/F: 13+ Detonation above 5500 rpm.
Encounted CAT overtemperature protection above 5000 rpm.

I went back one step to the run prior to detonation and instilled that curve. Here is the resulting PE curve.

0.0000 400.00 800.00 1200.0 1600.0
1.2277 1.2277 1.2277 1.2277 1.2277

2000.0 2400.0 2800.0 3200.0 3600.0
1.2529 1.2597 1.2655 1.2335 1.2665

4000.0 4400.0 4800.0 5200.0 5600.0
1.2800 1.2888 1.2984 1.3091 1.3188

6000.0 6400.0 6800.0 7200.0
1.3188 1.2859 1.2442 1.1919

In conclustion, I ended up just slightly richer than the stock PE curve. I would recommend. Adjusting the stock PE curve up about 7% for starters, and that should ensure that your aren't running too lean.
Make sure you turn off the COT during your tuning, if you don't already know.

Good Luck,
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

<small>[ October 01, 2002, 11:15 AM: Message edited by: NoGo ]</small>

 

Thanks, that is what I needed to know.

btw, my PCM was originally done by GM Racing, and anything above 25% is WOT, and my car is NEVER had part throttle (quite literally). It is either WOT or Idle. I don't know how this affects the computer, but it is hardwired and re-sets every time I start the car.

Anyway, you have answered my question. The LS1edit manual says you can enter negative numbers in the PE cells, but now I now what to do.

Thanks for all of the advice.

Dave

<img src="http://www.metricchemical.com/sig02.jpg" alt=" - " />

 

correct me if i'm wrong, but i believe that the number in the cell represents a fraction of the 14.&:1 optimal burning for gasoline combustion engine.. like this

you take the number in each cell, divide 14.7:1 by that number, and that is the a/f ratio that the computer tries to apply at that load and rpm in power enrichment.

14.7/ 1.2 = 12.25 and 14.7/1.3= 11.30

12.25 and 11.30 representing the desired a/f ratio

this makes sense with the above that the larger the number, the leaner and v/vs.

is this right?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by MIGHTYMOUSE:
<strong>correct me if i'm wrong, but i believe that the number in the cell represents a fraction of the 14.&:1 optimal burning for gasoline combustion engine.. like this

you take the number in each cell, divide 14.7:1 by that number, and that is the a/f ratio that the computer tries to apply at that load and rpm in power enrichment.

14.7/ 1.2 = 12.25 and 14.7/1.3= 11.30

12.25 and 11.30 representing the desired a/f ratio

this makes sense with the above that the larger the number, the leaner and v/vs.

is this right?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I originally believed that it was a percentage enrichment, but I am starting to side with you now. I have been doing some reading, and additionally alot of the EFI Live folks are reporting target a/f ratio's of the PCM at 11.9 when at WOT.

The stock PE is 1.2404 The stock target a/f at part throttle is 14.7368

14.7368 / 1.2403 = 11.88

Where did you get your info?