I have the GM Stage 2 kit. I want more power now. I have a JBP header and Down pipe sitting in my room. just waiting 2 more weeks to get that put on along with a new cat-back. Would it be safe to run a 2.85 without a tune or should i just get a 2.9. where can i order either of these pullies from.
Thanks

 

I have been thinking about a 2.9 my self. One that is of course interchangable with the GM hub. I have no idea how much of a gain can be expected though.
Do you know if the boost bypass mod needs to be done to run this?

Bump to the top

 

I think you can buy the gm stage 3 pulley by it self, I think its a 2.9''.

 

2.85 is O.K.....
I run a 2.9" with no worries
times, and dyno listed in sig. (found elsewhere)
use the search button.
(will P.M. dyno chart, and timeslip to origonal poster)

 

technically the stage 2 is 77.9mm which is 3.06


And the stage 3 is 76mm which is 2.99


and ppl said that anything smaller than a 2.9 will make the injectors go static... (do they mean GM stage 3 pulley at 2.99... or do they infact mean 2.90???)



With that being said, will a TRUE 2.90" pulley (not the 2.99) **** up the injectors?


a true 2.90" pulley (2.9) would be a 73.66mm


I noticed that CobaltPerformanceParts has a true 2.90" pulley... which is smaller than the "2.9" that GM has (really a 2.99") Will the injectors be okay:?

 

2.8" ZZP for you.
me too...

but if you can't hit 13's on stage 2, your most important MOD will be driving.

 

I am pretty sure it is the true 2.9 that is safe, not GM's almost 3.0

 

don't post what you have heard as 100% truth.
Look at my #'s and tell me you can't run a 2.9" pulley.

come on, buddy... go post in the war stories section... get out of my performance section.

 

Hey Scottdo7, how long did it take you to get your jbp header after you ordered it from them? I am going on a month and they are telling me it will still be another 3 weeks.

 

I think you misread what i said... i was kinda typing it as i was thinking of it, so it might be partly my fault.



I was stating what i heard... and asking if this was true.


Besides, i heard that the injectors go static UNDER 2.9"... not AT 2.9" so that is why i was asking if it would be safe at a TRUE 2.90... ASKING not telling.

 

I was running a 2.9 with the GM Stage tune. Every thing seemed fine. I didn't have an A/F gauge or a way to monitor my IDC's but my car didn't blow up. The car ran pretty strong, a tune will benefit you because there is much to be had with the Stage tune. It's pretty crappy.

 

I'm runnin' a 2.85 and love it... not much high end gains, but lots of low end grunt! 18 PSI on a cool morning easily! 17.5 most of the time!

 

where did you get your 2.85 at??? I order my header and downpipe 2 weeks before x-mas and got it in the middle of Feb. I just got done putting their intake on. it sounds great.

 

contact Nate -
https://www.cobaltss.net/forums/members/nherbst454-11117/

he'll make any size and to fit GM stg2 hub

 

That would be the fella there! He got it too me quick, and it was perfect for the Stg. 2 hub!

 

I have the 2.85 that fits the GM hub from nherbst24 <---I think thats right, havent put it on yet though IMO the best buy for $50

 

That is the one I am using.... 2.85 polished!

 

I got exactly what you meant, I just don't think he did.

 

Its all good.. hope he sees this... dont wanna make anyone mad.

 

with my math I got 3.04? where did I screw up? Anyway I was gonna get a 2.85 made to fit the S2 hub.

 

so i will be fine with a 2.85 with the GM tune? thanks for the input.

 

Personally I wouldnt go under a 2.9 without an AFR, and I would like to have an AFR for anything smaller than the stage 3 pulley (3")... But thats just me

 

not sure.. i just used a online mm to inches converter... and i doubled checked them with a few more online converters

 

skipped reading after half a page. too lazy atm

Syp, u were right on, cheversalesman misread and made an ******* assumption.

just run a 2.9 pulley. end of story.