What would the difference between a 2.9" and a 2.85" pulley be? How big of a difference would it be?

 

not much...

 

That's what I thought. Thanks for the input.

 

Its .05

 

its not worth it. if you have a 2.9 atleast go to a 2.7

 

You will notice very little difference... a little heat, and a little bit of power albeit you won't notice in the butt dyno!

 

That is what I thought, but thought I would ask just to be sure. Thanks to everyone for the input.

 

your injectors will notice it on that gm stage 2 tune, i will tell you that much. 2.85 on a stage 2 tune = static.

 

Well that isn't entirely accurate.... but it will **** your injectors off! I ran a 2.85 on a GM S2 tune with an Intake for 6-7 months before a good tune!

 

Actually it is accurate. The 2.85 pulley at 7,000 rpms = 42lbers going static.

 

Okay man... whatever you say...

::shakeshead::

continue on

 

Do you know what the idc's are on a 2.85 pulley at 7grand?

Edit: nvm, its not worth the argument anymore im tired if it all.

Feel free to run 2.8 pulleys on stage 2 tune, yea!!!

 

each car is different. the majority of our cars will go static with a 2.85 or 2.8 pulley, but some wont. as a general rule, its not technically safe to go below 2.9 on 42#s because the injectors may be overworked and cause a lean condition.

 

Do it i have been running a 2.85 for over 40,000 miles wih no problems.... otheer than a slipping clutch

 

Matt at tune time told me i didnt need 60s when i told him i was just putting on a 2.8. he said my 42 would have been fine if he were to tune for it...anyway back tot he point....not a big difference. I drped to a 2.8 from a 2.9 and had very little difference...

 

everyone knows idc are more like suggest values and that its perfectly fine to run %120+ on them... geez guys...

 

kids these days they go by what they hear on this forum ive ran a 2.8 on my gm tune since last september and guess what im still running strong oh yea and forgot to mention still running a 65 shot. m dub knos where im coming from hes ran a 2.8 as well it dosent run static like its gona blow up but yea its a little hard on the injectors but theyll get over it

 

if you want to argue with him, how about you argue with the guy that tuned his car and has had ZERO problems with it.

 

It's possible but the engine doesn't go lean.

I have been running that setup for over a year, with nitrous.

 

No one ever takes into account where these different cars are! Higher altitudes produce less boost, thus less air into the motor and less fuel needed. My IDC's on 42's and 2.8 at 6,000ft above sea level are in the high 80's low 90's, not perfect but not too bad. The same can also be said for temperature as well...

 

sorry to interrupt, but if anyone wants a 2.85" for the gm hub....buy mine
https://www.cobaltss.net/forums/parts-66/2-85-pulley-fs-trade-131101/

 

Everything depends on the altitude/weather. It's different for different people but it's 100% true that you injectors go static on a 2.8 above 6500 but two things:if you don't rev past it often (daily driver) then it's not an issue, and it's not clear that it's doing damage to the injectors.

Actually there will be a bit of difference (acceleration and heat wise) between a 2.9 and a 2.8. If you're a "maverick" you'd probably go 2.8; if you're "cautious" you'd go 2.9.

At what rpm?

 

6800 to red line... I only boost 15-16 psi on my 2.8 up here...