dervin3

I've got a 2.9" pulley coming this week to go along with my other mods listed in my sig. Is the 2.9" a simple bolt on mod as in no tuning will need to be done?

Edit: I did do a search but since it's been awhile since I been on here, there's so much info going around on the whole 2.7-2.9" deal, I couldn't find a solid answer.

Matty

Just bolt it on.

A HPTune does wonders though.

dervin3

Speaking of HPTuners, my local performance shop does tuning and I ask if he could specifically tune cobalts and he said yes. Now is HPTuners the only Cobalt tuning software out there or are there others? Sorry, I'm idiotic when it comes to tuning because I've never done or had it done before. I'm slowly learning more and more about it each day though :css.net:

Matty

Yes HPT is the only option right now.

dervin3

...then he must have HPTuners...

Shermen

you dont have to tune it buy the injectors are maxed out at about 6000-6250 rpm. but if you get tuning get the tuning from tag. they will set you up nice.

martinsmu

^^^ no they are not. They dont max out with the 2.9, thats why people are slowly getting those now and not the 2.8. Those Max out the cycle around 6400 RPM

retrop

Where they max is completly dependant on temp and pressure, jsut like whether or not the 2.9 maxes out....

I have seen my injectors max w/the 2.8 at 6200, and others run the 2.8 fine on the stage 2 injectors. If the pulley can be run or not depends on the amount of boost and airflow you are seeing

martinsmu

^^^ your right. But 2.8 do tend to max out the injectors preatty much all types of condition and altitude (near redline obviously). Where the 2.9 are damn near safe for all purposes.

Shermen

will it maxed out on mine. was like 110% or something like that.

RedlineBrian

I've been running a 2.9 with the stock GM Stage tune for quite some time now. No problems whatsoever. You feel a little bit more pull and see a little more boost than the stage 2 pulley.