I was wondering if anyone can tell me how large of change in the pe table needs to be made to make a substantial change in the A/F ratio?
like say for instance my A/f ratio is 10.5:1 with a PE multiplier of 1.21 if I changed the Multiplier to 1.19 how much would that lean my A/F out?

Also Does anyone have any experiance tuning the VE tables on a Turbo LS1? I was thinking that maybe the VE tables should be changed in the areas when the engine is not seeing boost to compensate for the extra restriction from all the intake piping. What are your thoughts on this?

I'm tryiing to figure out why my car is getting crap for gas milage, it surges under light acceleration and the throttle responce is non existent. All the L-trims are in line right around -2% to -6%. Any suggestion would be great.

 

multiply your target A/F with the PE value...and you'll come up with the mixture that a wideband should replicate. (10.5 * 1.21 = 12.705)

 

The PE table values are F/A multipliers. The PCM's desired A/F ratio will be 14.7/PE value. The actual A/F ratio may not reflect the calculated value but you can adjust for the desired ratio very easily.

Going from 1.21 to 1.19 would give you an A/F ratio of ~10.68.

Tim

 

nevermind, he's right...don't listen to me. I had bad coffee or something...

 

Ok so lets see if i got this right. I divide 14.7/ 1.21 my AFR should be around 12.1.
is this correct? Also being that i'm running FI does that throw this calculation off any?

 

Theoretically yes... but the actual O2 readings will likely deviate from the desired A/F ratio. The correct thing to do is use a wideband O2 to measure the actual A/F ratio and adjust from there. Tuning off of calculated values may get you into trouble.

Tim

 

I just realized you are in Orlando... we are having a dyno day at Macedo Motorsports this Saturday. 3 Dynojet runs for $50 with wideband if you are interested.

Tim

 

In simple terms I've found 5% changes affect A/F .5 of a point.Also weather conditions affect what your end result is on a boosted car.

 

Ok cool yea i know that i can't rely on the calculations but the last time i dynoed my A/F was 10:1 in the upper rpms. so i was gonna pull some fuel untill the next time i can get it on a dyno but i don't want to go to far. I figured if i reduced the pe tables by 5-8% even if that only drops my A/F to 11:1 thats alot better then 10:1. Thanks guys.

 

Where's Macedo located and who's we? Are you
with a car club?

 

I have my IFR table setup so I can change still get 14.7/PE = afr on my in car wideband on my Incon setup. With the different injectors, fuel pressure regulator and pump, etc the PE table was not that close.

I have changed my VE table to match the calculated values of approximately 35% higher than stock, but got absolutely no change on the ltft, or wideband. VE table is back stock again.

Gary

 

Were you at the corner of Orange Ave. about 3 or 4 weeks ago? I talked to someone that had a single turbo setup on a T/A.

Macedo is just north of the intersection of Princeton and 441. I do the LS1 tuning there on the side. We will be starting around 8 AM on Saturday. If you have any questions shoot me an e-mail. trs74@otcdsl.net

Tim

 

yep that was most likely me i'm up at orange and 50 every sat. night.

 

Woo WOO to the corner!! sorry guys
tom was messing w/ excel and came up w/ this.
i use something like it for PE tuning LT1s.
its protected so you cant change stuff you didnt mean too, but there is no password to un-protect it.

any feedback, let me know.

 

Dude that is freaking sweet, Thanks man.
I'll punch in the info when i get home and let you know how it turnes out.

I'm gonna owe you a few drinks if your out this FRI.