Traded my 60#'s for 42.5's and some cash because I just bought hpt and am hurting on money, figured hey, free gm stage 2 tune all I need is the pulley. I'll be getting 60's back when I learn the full dynamics of tuning but not right now.
Question is, would you guys have anything bad to say about a 2.9 on the stage 2 tune by itself? I'll be messing with my maf calibration and other things when I get my wideband and I learn while getting into tuning, and I won't go lower than 2.9 on the 42's for sure. Any opionons, suggestions, comments?

 

2.9 is a little too small..

you dont need your wideband to tune your maf.. you can use the fuel trims.

i have a link to show you how without using a wideband if you want to see it.

If you did this, you could get away with a 2.9 on the 42s for sure... if you knew what you were doing, a 2.8 could work (i never had a problem)..

 

u think i should just go with a 3" then?
hmm interesting..go ahead and pm me it or post it whichever lol...shortstack to dtcd's informational rescue like usual

 

i have a 3 inch the whole motor runs way to rich i would do a 2.9

 

also what would you guys really change in hpt to do a tune for 2.9 on the 42s. i'm assuming pe maf and some timing? idk about what else though.

 

i run a 2.85, have been for over 2 years and it runs great. Some other people run the same here, I've heard mixed opinions though. A lot of people say don't go smaller than 2.9 and a lot say 2.85 is fine. Then again some people say don't go below a 3.

 

I used the 2.8 and was just fine .

 

on the gms2 only? no tweaks and such?

 

No no no no no.. custom tuned...

 

mine is on stage 2, but a lot of ppl run that set up. A lot of ppl say I'm maxin out my injectors though but like i said no issues here

 

2.85 on the stage 2 is a wee bit iffy...

 

ya i was running another tune on stock injectors and pulley and got 120%idc at 6.6k i think i was like uh, no. lol. flashed stock back and waiting on these now.
nothing wouldve happened im sure but i'd rather play safe than sorry.

 

Well.. IDCs arent accurate for our application. you have to look at the pulse width.

 

yea thats what a lot people said, but then again I researched to see if others had issues before I did it and no one had any history of problems with that set up. So every thread I've talked about this about half say I shouldn't be doing it and the other half say its nothing to worry about. Been running it for over 2 yrs. Then again I don't push my car very often.

 

of the injectors? im at school so i'll have to ask lol, is that a paramter in the scanner?
i'm also thinking maybe if i can get my hands on a st3 tune that doesn't knock ac some how i could do that. full cooling mods besides meth so i'll be fine there.

 

Yes its in the scanner..

The s3 pulley is 3"... im pretty sure everything is teh same besides the no2 algorithm in the s2 and s3...

 

I had the gms3 on a stage 2 setup and right around 5500 rpms and above i would run out of injectors, upgraded to 60s and no problems.

 

im running 2.9 on #42 stage 2 injectors and im running fine

 

But is it the stage 2 tune?

 

oh no but i have heard many people run 2.9 on stage 2 kit and be fine

 

I'm running stage 2 with nate's 2.9 pulley ..u can feel the difference from the stg 2 pulley and the 2.9..been on my car for about 20k now and not a single prob