After reading 30 pgs i still dont have a crystal answer. Can i go from 3'' pulley to 2.9 witout getting TUNE OR REFLASH? Mods- stage 2,headers, GMPP Exaust, 42 injectors

 

yeah you can i just recomend having a wideband so you do get too lean when its cold but you should be fine gm stage 2 tune very rich anyways

 

Thanks. Will i increase boost? is it hard to install widiband?

 

I ll let ya know. Im going to a 2.9 pulley with my gm stg 2 kit. Im also putting in a front mount heat exchanger. I have gmpp exhaust, gmpp header, injen cai, 3 in catless downpipe, ingalls torque dampner, G85. I heard it will increase boost. You also should run a cooling mod as well.

According to GM's website you can use a stage 3 pulley with the stage 2 kit as long as you install a cooling mod ex heat exchanger or dual pass end plate.

 

I have GM stage 2 with a 2.9" pully, header back intake and im still mid 10's at WOT in about 5-6 degree weather i think it was

 

oh i forgot that i have a CAI and and h/e and option b.

so when you say still running 10's, is that good or what?

 

Yes you can. Your IDC's will run extremely high but to answer your yes you can. That's what I have on my car and I have had no problems with it in almost 2 years.

The GM Stage 3 pulley is 2.99. He's talking about running a 2.90 wich is what I have. I ran mine w/o cooling mods for a while but cooling mods are definitely something to look into.

 

i've looking for a 2.90 pulley but can't find one. i'm at work right now so i can't really be going from website to website. where can i buy one from?

 

OTTPerformance sells them.

http://www.ottperformance.com/Cobalt...duct_info.html

EDIT-If you already have the GM Stage 2 then you will need the pulley for the GM HUB. If you aren't GM Stage 2, go with OTT's Stage 1 kit. Tune plus all part for ~$500. Can't beat it.

 

hey thanks alot. looks great and the price is even better but my pully only has 4 bolts. this one shows 5, will it still fit? thanks alto i really appreciate ur help

 

You have the GM hub. Order the pulley for the GM style hub and it will be a direct fit. It's the same price.

http://www.ottperformance.com/Cobalt...duct_info.html

 

thanks, i just purchase one from OTT and shoud be here by no later than Tuesday. would i gain any HP or boost?

 

Are you running just GM Stage 2? By going to the 2.9 on a GM Stage 2 tune you will notice a small gain. Boost will be ~17.5psi instead of 15. But it's not going to be some gigantic 50+ hp to the wheels gain.

 

you most likely wont see 17.5 psi with a 2.9". you should see 16ish. 17.5 is usually seen with 2.8"s

You really should get a wideband to watch your afr...

 

im currently looking at Widebands but i really dont know or won't be able to tell in my AFR is good or not becasue i wont know the difference between good and bad. A 5 sec explanation will help if you will?
How hard is it to install a wideband from 1 to 5?

 

Im currently getting 16.5 psi boost with my GM Stage 2 kit plus other mods. 2.9 pulley and heat exchanger will be here tommorow. So I figure I will see the 17.5 to 18.0 Psi of boost. Cant wait.

 

i just put my 2.9 on yesterday with my stg2 tune ...i have a injen cai and magnaflow exhaust and its 90+ degrees here right now im wicked nervous i dont have any cooling mods yet

 

Stage 3 and 2.8, no problems yet, 33k and going strong ( knock on wood ). Mod in signature, and if you don't run wot all the time I think you will be fine

 

Mine will be here tommorow. Yea

 

really wow i see 16 all day on my gm stage 2 pulley in 80*+ weather and at one point when it was cold it was going to 17 and i backed off and no i dont have a clogged cat just to let you know but hey some car are different i guess

 

Stage 2 runs better with a 2.9. I've had both on.

 

I have 14 psi with my gm stage 2 lol but it gets the job done

 

Going from stage 2 3.11 pulley to a 2.90 pulley you will probably gain about ~10-12hp. As far as the amount of boost you will see it just depends. Higher boost does not really mean more hp, in fact lower boost usually means the air flows better which means more hp. Typically you will see around 17 with a 2.9, but with a header and exhaust usually that number will be lower since you have better flow. When I put my header and exhaust on I saw about a .5 - 1 psi decrease. It also depends on your elevation. The higher the elevation the lower the boost will be.

 

we just put a 2.9 on my buddys blue05ss/sc he posted on the first page well last night after we installed it we went for a ride but after id say of about an hour drive the car was bogging at like 5K he has no cooling mods does that mean hes running way to hot and pulling timing or is it something else
any help would be appreciated cuz hes kinda freaking out about it lol

 

yeah if you are at sea level or have a stock exhaust you might see higher psi. but like we said. psi /=/ horsepower

yes, the pcm will pull timing when the iat2 reaches 140* or more. need cooling mods when you drop below 3" pulley