Stock A/F Ratio - how far off>

[Dominic]

For those of you who have tuners - how far off were your stock A/F numbers? Did you need to tune any of that, or did you just play with timing? I just wonder how close my car might be to being right from factory with a few airflow mods (intake exhaust !MAFscreen). I know its a dumb newbie post and I should jsut get a tuner, but hey - asking is free :D

[foff667]

most i see are about a full point to two points off of where you WANT to be...ie 11.0:1-12.0:1 whereas you want it to be around 12.8-13.0:1 at wot.

[Nachius]

I haven't looked since I sold my software, but I THINK I ran high 11s, although I didn't mess with it at the time.

[saltnvinegar6287]

Your LTFT being 0 is where your car wants the AFR to be, right? When you adjust your AFR, are you changing the LTFT table, or are you changing the IFR table which causes changes in the LTFT table? Trying to get this all sorted out in my head b4 start tuning.

[foff667]

Originally posted by saltnvinegar6287:
Your LTFT being 0 is where your car wants the AFR to be, right? When you adjust your AFR, are you changing the LTFT table, or are you changing the IFR table which causes changes in the LTFT table? Trying to get this all sorted out in my head b4 start tuning.

to an extent your correct...the trims really is just how much the computer is compensating to get your fueling correct...your trims could be +12% but your a/f might still be 14.7:1...its just the computer saying hey something is wrong with some of your tables, you might wanna get those straight, nothing more for the most part.

[arthansen]

Your fuel trims (LTFT & STFT) are simply correction factors to your VE table. Your car is constantly comparing what it wants and what it gets (mainly fron info from the 02s).

Here is an excellent description of what the VE table does.

http://www.hptuners.com/forum/YaBB.p...num=1101917527

Now here is a description of how to adjust your VE table.

http://www.hptuners.com/forum/YaBB.p...num=1100894562

Finally, the procedure in the above post will not quite work on the V6 because of different controlls on our cars. Here ia a thread where I outline how to adjust the procedure for our cars. Go down to the last post in this thread (the whole thread has good info but the breakdown is at the end). This is how you get your LTFT into line.

Good luck.

http://www.hptuners.com/forum/YaBB.p...90;start=19#19

[foff667]

hey art maybe you know...cars with all 80's in their ve would it still work...some of those v6 ve tables are just so jacked up i didnt even wanna touch them.

[arthansen]

Yes. Those cars are simply relying on the LTFT to make corrections. That results in poor throttle respons. Those cars perticularly can benifit from VE table tuning. Basically, GM was being lazy and did not put in the time to adjust the VE table.

Same thing for the injector tables on some of our cars. The injector flow rate should be different for different MAP pressures but many cars have the same value in every cell. Once again, GM being lazy.

Besides, why would it matter in a V6....no one cares about V6 performance (at least that was there philosophy)!!

[foff667]

thanks...now i gotta find one to toy with [img]smile.gif[/img]

[Drone51]

art so in that thread your telling about how to adjust the ve table are those the correct steps just wanted to see if there was anything else because when you wrote that it sounded like you had not done it yet, just wanna make sure thats all

[saltnvinegar6287]

arthansen, thanks for all that great info! you make it sound so easy

[arthansen]

Those are the steps. At the time I had not but I have since. Once you are done, just set everything back to normal (except the VE table) and plug the MAF back in.