I would like everyone that is running smaller pullies with GM stage tune to post what max psi is being achieved with specific size pulley, This may have been discussed already but I think the updated reflashes bleed boost beyond 15 psi regardless of how small the pulley that is being used, however boost still builds sooner so more power is still gained.. In my case I am running 2.85 and max boost achieved remains at 15.5 psi just the same as the stage 2 pulley..

 

i'm getting 16.25psi (give or take .25) with the gm stage 3 pulley on the stage 2 tune. mine is an 07 that got stage 2 back in march.

 

I hope I see more than 15 psi with the stage 3 pulley because I just ordered it. I was hoping to at least have it jump up to about 16.25ish. I hope there is at least a little bit of a noticeable increase. I should have it on by the weekend.

 

I am seeing 17psi with Pulley Boys 2.8" Pulley with my GM Stage 2

 

I don't think the stage 2 tune bled boost like the stock tunes did. I'm pretty sure the stage 3 tune when it is on the non-100 octane mode is the same tune as the stage 2, that is why I wanted the stage 3 pulley. I would like to get the dual endplate over the summer just to help with a little more cooling.

 

what is the smallest pulley you can go with safely with the gm stage 2 tune?

 

From what I read a true 2.9" can be run but a tune wouldn't hurt. I think the IDC were even pretty high just on a 2.9". The lowest I am going to go on mine is the stage 3 pulley unless for some reason I feel I need more I will have to get 60s.

 

stage 3 pulley is 3.0 right?

 

i think stage 2 is 3.05ish and stage 3 is 3.01ish but i'm not good with conversions like that. i'm running the stage 2 pulley right now and i peak around 16.5 at almost 7,000rpm. i think boost has alot to do with elevation. i had the reflash done after the new tune came out.

 

Stage 3 is ~2.992".

 

stage 2 77.9mm. 3.07 inches
stage 3 76mm. 2.99 inches.

 

Im going to put a 2.9 pulley on the stage 1 and see what happens. From what I hear its the same tune.

 

so 2.9 pulley is safe for a stage 2 tune?

 

So far GM says that the 2.99 pully is safe on the 42.5lb injectors.

anything else is up for debate i think.

from what i hear, 2.85 is supposed to be right around the 100% IDC mark
so alot of people are going for the 2.9

 

18.5 with all my mod an the sig

 

My boost level is in the pic in my sig. Stg II with 2.9"pulley

 

I have seen 18 psi with my current mods.

 

i see 16 PSI with my 2.9 and stage 2 tune

 

I'm suprised you see this much boost with only a 2.8 and the gm manifold

 

If I go with a 2.9" pulley on the stage 2 tune will I need a smaller belt or will the stage 2 belt work?

 

You will be fine. The stage 2 belt is extremely tight. I'm pretty sure the people running a 2.8" just use the stage 2 belt as well.

 

I have seen it as high as 18.5-19, but now with the dual-pass and such im seeing about 17 most of the time, unless the car is really hot.

 

you will not see 18.5 with a 2.8
the ONLY time you will see it is in 5th gear, at WOT 145+ mph.

 

Well, thats what the gauge said. I couldn't give a ****, boost pressure is ******* worthless anyway. I could have 60 psi, it just means that the air is not going into the engine.

When its 90+ outside, with the same humidity, and the car is 210+ coolant temps, in third I bet I was seeing 18-19 psi. This is Miami

 

then again, these are autometer boost gauges. you would get a more accurate reading if you stuck your ass in a bucket of water and farted.