I want to know if it is safe to drop pulley size. I have a 2006 ss/sc and have GM Stage 2. 42lbs,injen cai,and bad mab header, 3'' zzp dp, and 3'' all the way back. I want to drop pulley to a 2.9. and I live in San Diego and only have 91 octane. I will also get a zzp pcm tune.

Please let me know... Thanks

 

I'm curious if the injectors can handle the fuel needed for the 2.9, my guess would be yes.

To go from a GM pulley to a 2.9, you're going to have to do a hub swap on the supercharger.

 

Should be fine but don't get the ZZP tune. It is just a canned tune and will require 93 octane. Just buy the pulley and get a trifecta or hp tune and specify that you will be running 91

 

oh, and I miss San Diego.. Send me some of that sun to Germany, please and thanks

 

u should be fine i ran 42's witha 2.9 for awhile..its all depending on the tune tho

 

If hes a GM stage 2 he already has a hub. Zzp sells pulleys for the GM stage hub. No need to do a hub swap

 

What if i dont do a tune right away???

 

if you donjt tune right away you SHOULD be okay.... might get a CEL though

 

Should be ok. Might lean out a little since you will be running more boost but as long as you don't beat up on it you will be ok

 

wow at the answers so far...

Yes 2.9 will be fine on gm stage 2 tune, No need to retune. Dont get me wrong a re tune would probably net better gains just because the stage tune sucks but you dont NEED it. ZZP sells 2.8 and 2.9 pulleys for your stage 2 hub, just unbolt it and bolt this one up. By the way im currently running a zzp 2.9 on my gm stage 2 with no issues and it woke my car up