svede1212

iTrader: (3)

I had a chance to read a tune on a comparable '04 LS1 GTO and compare it to mine. the only basic difference is i have a stock cam and the other is a "little" aftermarket cam. most of the parameters are the same but the timing is 3-5* less below 4,800 rpm on the "Pro" tune and a huge difference in AFR in PE mode

here's what the Pro has for PE AFR:

1,600-3,200 RPM
12.486 AFR

3,600-4,000 RPM
12.262 AFR

4,400-5,200 RPM
12.007 AFR

5,600-7,200 RPM
11.772 AFR

mine runs:

idle-2,800 RPM
12.6 AFR

3,200-4,400 RPM
12.8AFR

4,800 RPM
12.6 AFR

5,200-5,600 RPM
12.9 AFR

6,000 on out
12.6 AFR

what's up with that? i've never read of that rich of a WOT tune.

Ryne @ CMS

iTrader: (10)

your tune seems better

svede1212

iTrader: (3)

believe me i was hoping so, that's why i'm asking. the "Pro" tune (my buddy paid $400) was from a supposedly reputable tuner in the Detroit area. i use a LC-1 wideband and am pretty meticulous. another thing was his VEs at peak torque (@4,800) are 95 and mine are 99 to achieve commanded AFR. either side of peak torque i'm higher too

I8YOR50

iTrader: (1)

they probably tuned it to be safe, and not for max power on the ragged edge!

wait4me

iTrader: (10)

Sometimes cars dont make more power being that lean. Depends on the car. Also, when cats are hot, they dont make the same power.

SSpdDmon

iTrader: (10)

Pro-Tunes tend not to touch the VE. If they do, it's mainly in the idle cells. They usually have a line of cars waiting to be tuned. So, the approach is to get the car on the dyno, dial in AFR, tweak spark a little, and hand over the numbers. Problem is, if there are issues like positive fuel trims, they are rarely dealt with. They got the car running the right AFR @ WOT by screwing with the PE, they got your numbers....so what are you complaining about? << This is the main reason why I chose to tune my own car. I like consistency.

svede1212

iTrader: (3)

not complaining. i did tune my own car and spent more than a month tweeking my VEs to get it right. i was just trying to understand the difference in tunes. thinking about it tho, the fact that they probably didn't tune the VEs would account for it. if i used my VE #s for WOT peak torque and applied it to their AFR it would change it from 12 to 12.6 actual, the same mine is. they are still quite a bit richer up top but at least in the 12s. it seems like a cheesy job to do it that way and they are relying on the MAF to take care of the rest of the VE table.

SmokingWS6

iTrader: (1)

The 'PRO' tune was unlikely running that rich at wot, they rarley touch VE, MAF ect. I'd be willing to bet when he commanded 11.8 to 1 your actual afr was closer to 13 to 1.