I have the gm stage 2 and im swapping the pulley out for a 2.9. I was just wondering if you need to mess with the tension when you do this or is it fine how it is

 

You should be just fine, no need to adjust anything.

 

what about a 2.85 on a stock SS/SC. Is it fine to run?

 

stick with the 2.9

 

wow.....

 

no.. no it's not, you need injectors and you might need an adjustable tensioner. You will also need a tune.

 

Sorry, haha I meant stage 2 not stock... my bad

 

cooling mods!

 

Agreed. Many people will say they've run the 2.85" fine on the S2 tune, but keep in mind it's a canned tune. It's not specific to your car and it's always recommended to get a tune especially when changing pulley sizes because that's a relatively big change in incoming air. A 2.9 is what most will say is best/safest to run on the S2 tune if you don't plan to get a tune soon, including Nate.

 

-bump-

do you need to take the sc off in order to swap from the s2 pulley to the 2.9?

 

i got a 2.79 on my stage 2 set up the belt does not slip at all.its running 17.5 lbs of boost.however it does not run smooth wot.it misses a little when i get on it,got to get tune

yes it is a lot easier,if you dont you will most likely strip the pulley bolts

 

if you're running stage 2, you shouldnt need the tensioner. the stage 2 belt is smaller than stock so you should be fine.

somebody correct me if i'm wrong.

but definatley get a tune, stage 2 tune is notorious for being complete ****

 

if he has stage 2 already he should have the shorter belt. if u go to 2.9 that should be it....nothing else required. If you go to 2.8 you need 60lb injectors and a tune. Cooling mods are NOT required but it doesnt hurt to have them

 

The stage 2 pulley is a PIA to get off because you have to use an impact so I would say Yes to taking off the sc when swapping to the 2.9...

 

i would recommend against using an impact wrench- i used one when trying to get my pulley off, and the threads on the pulley puller ended up getting stripped. just be patient and do it by hand with the pulley puller.

and yes, you have to remove the supercharger to do this.

 

Pulley puller?? You just use the stage 2 bit they give you with the GM Stage 2 kit...and combine it with a hand impact and that's how you get it off...

 

I absolutely hate these threads. Let me settle this for you real quick. Do you like starving your motor of fuel? Do you like running your injectors static to the point where they could seize? If not, don't use small pulleys on a rich crappy stage 2 tune. The lowest pulley you should use IMO is a 3.0inch pulley. Running a stage 2 and 2.9inch pulley I have seen IDC's injector duty cycles over 110% at 7grand. You want your idc's to be no higher then 80%. Anyone who thinks they can get away with a 2.79 or a 2.8 is just an idiot. I'm sorry but you should NOT starve your motor of fuel like that man. Get some bigger injectors, there not that much.

www.ottperformance.com great deal on stage 1 kits and or just 60lbers. GET THEM.

 

I have 2.8 on my car and it runs amazing. IDC is low and everything is running good.

 

That is because you have 60s...he was talking about running a small pulley on 42s...