AL,

Wanted to know what are good AFR reading for 20.5 psi with 93 oct. i am running a little rich so wanted to adjust them. what are good number for

1. 3rd gear WOT
2. 4rd gear WOT
3. idle
4. cruising at 60-65mph.

please provide a range, others are welcome to pitch in as well.

Thanks

 

at WOT you generally want to be in the low 11's. Around 11.3-11.4
at idle... 14.5-7 is pretty good
at cruise... you can take it to about 14.7-15.0 (should give you good gas milage)

 

yeah, I idle around 14.7-15.0 and cruise at 14.7 and WOT is mid-high 11's, which is a little more aggressive.

 

14.7 is standard for closed loop operation. The ECU automatically and constantly tries to achieve this at all times when not at WOT, so you don't need to mess with it. At WOT on 93oct with only 20.5psi peak, you can do 11.5-11.7 all day. 11.3-11.4 is fine, too.

 

i wanted to be on the safe side that is why i am at 20.5, but is 22 pretty safe with around 11.3-11.4 WOT.

 

Also of note, is when you first start a cold car it will run really rich* untill it warms up. You can usually tell when it gets warm because it'll switch closed loop mode and run ~14.7.

* corrected... I originally wrote "lean"... Jim_Paterson corrected me.

 

It runs rich when you start a cold car.

 

Correct, and the ECU gradually leans out the mixture as the engine warms up and goes into closed loop mode.

A cold motor needs more fuel to help it go kaboomey.

 

You are correct. My bad.

 

Yeah, man, tons of us run 21-22psi all the time as long as it's on 93oct. 11.3-11.4 AFR is still conservative. Our optimum area is up around 12, but it's too dangerous to tune that close to the edge, so Al usually keeps AFRs in the 11.1-11.3 range so that customers are safe in almost any conditions and even with a bad batch of gas.

22psi and 11.3-11.4 AFR on 93oct is no problem USUALLY, but every car is different.

 

Does that mean with a TTM I can run 22psi with 93? the ttm is tunes for 93

 

It depends on what you were tuned for. When you send in your ECU, you told Al what psi you were running, and that is the PSI you should continue to run.

 

I didnt tell him any specific psi, but i figured since the ecu runs rich, and im running higher oct 93 i could up the boost a bit. I think Al tunes for 19 as a standard?

 

Oh no, I don't think so. 19 is lower than stock, so I can't imagine tuning for that as the standard. I always tell Al exactly what boost I'm running, and I tell everyone who sends in their ECU to tell him the boost they're going to run. You should be no less than 20-21psi on 93oct...

 

you can run pretty lean just cruising. a stock car runs 15.5 afr's. I run my car as lean as 16.0-17.0. after that the car misfires.