I'm doing my WOT tuning.. but getting very low on the PE/RPM numbers.. mostly about 1.060 to 1.090.. Now I notice that the PE/TEMP numbers are .030 to .045..

Do these add together for the "total" PE? for instance, if the PE/TEMP value is .045 and the PE/RPM value is 1.060, does this mean I get a total of 1.105 total enrichment????

 

The both effect fueling at a given point - if the add up to make a new scaling factor, or both simply scale I couldn't tell you. Christian Milliard has a formula worked out for the LT1 version's, but I do not know if it still applies. You could try changing on and then the other by large amounts (rich preferably) and record the resulting plsewidth - you should be able to approximate the relationship from this.

I would suggest leaving the coolant table alone though, and just modifying the rpm table to suit your needs.

 

Here's the deal... I have a stock MAF and stock MAF table. I have 42# injectors. I tuned the ltrims to -3% or so via the injector flow table.

I have a near perfect cruising setup and my onboard wideband shows a 14.66 average A/F

I then began on the WOT A/F and found a staggering 10.6:1.. I reduced the PE/RPM table by 5% and the A/F improved to 11.2:1. I then reduced the A/F again, I'm at about 1.050, and got A/F of 12.2:1. I then took the PE/RPM all the way to 1.000, so should be 14.66 right? Wrong, .. now 12.4 at WOT and 14.66 at cruise.

Obviously, something else is giving me some fuel at WOT.. Anyone got any ideas?????????

 

Nevrenuf
I know you have a stroker engine and it sounds like your getting close to figuring it all out. My Superchips tunning on my ARE 422 has so many problems,I need a starting place to get this thing running right.
Do you think I could see what you have done so far to get an idea where to start. Thanks for any help.
Tom Hall

 

You are at near perfect at cruising because that's what your stock o2's and l-trims do; keep you there.

At WOT your target a/f ratio isn't going to be 14.66:1 - it's probably closer to 12.9:1. This is calculated based on your MAF, and then the PE's are added.

To be accurate you really just need to finish tuning on a real wideband and verify your final numbers.

 

Chris.. I am at 12.2:1 WOT despite all I've done. I DO have a wideband setup, permanently installed in the car with it's own controller, serial interface, laptop interface, PCM feed, etc. accurate from 10:1 to 20:1.. I know I am still rich and losing power. I picked up 19hp on the dyno just going from 10.6 to 12.2....

I'm shooting for 12.6-12.8 for NA

I plan to get this program right and then develop another with 4 degrees less timing and a fat 12:1 WOT A/F for when I spray this sucker

 

Why not lower the injector flow tables to lean it out and then add fuel back in at part throttle in the MAF table?

I would like to know once and for all where we are suppose to adjust part throttle fuel. I've heard VE, injector flow rate and MAF.

 

For me, my approach is "whats right is right".

The stock MAF tables produce correct A/F on a stock motor. If you don't mess with the MAF, don't mess with the tables.

Injectors can be tested for flows. Get the right info in there and go for it. If you don't mess with the MAF, and have new injectors, tune with the injector table.

If you know the MAF and Injector tables are right, then the VE is the place to go. For me, I was able to get good trims with just the injector table.

However, I am very rich at idle. The car idles fine but I can smell that it is quite rich. It leans out back to 13.6 as it warms up but starts out very rich. There must be a table for that somewhere than Ken just hasnt found yet... Its funny that Idle is never 14.7, it always returns to 13.6 no matter what I do. However, the instant you put your foot on the pedal at all, the AF jumps to 14.7.. So, I'm thinking there is a sort of "idle enrichment" table vs. Temp out there.. adds fuel at idle based upon coolant temp.. Just a thought....

I've decided on a small experiment. I am going to set both PE tables to add NO fuel and confirm that I maintain the 14.7. Then I am going to try 1.050 more fuel in the PE/TEMP table and see what AF I get. Then I am going to put the PE/TEMP table back to zero and put 1.050 in the PE/RPM table and see what I get. Then I am going to put 1.025 in BOTH tables and see what I get. I should be able to learn the facts about PE behavior from this experiement..

Good thing there is no limit to PCM flashes!!!

<small>[ March 24, 2002, 07:25 AM: Message edited by: nevrenuf ]</small>