my car has stage 2. the pulley has a 77.9 stamp on it. is this pulley a 3.0- 2.9. or 2.8

 

3.09 or something like that. Its basically a 3.1" pulley, IIRC.

 

77.9mm Go on google and find a simple converter. Better yet, 25.4mm per inch.
77.9/25.4= Do the math

 

yeh its 3.066929 in. so pretty much a 3.0in pulley

 

sorry for this stupid questions, but i bought the car as is and im trying to figure out what upgrades it has. how can i tell i have 42 or 60 injectors? i want to go a 2.8 pulley, do i need a tune?

 

Youd have to pull out the injectors to see what they look like..

if you have the 77.9... your probly a stage 2, which is 42 pound injectors..

 

Some of the 2.8" pulleys were made to look like the Stg2 pulley though. So it is possible that you have a 2.8 pulley that has 77.9 on the side.

Mine was like that.

1.) Is it on stock exhaust?
2.) What PSI are you hitting?

If it is on Stock exhaust and it is hitting 15psi... you have the stg2... if it is hitting 17+, then you have the 2.8"...

 

can i do 60 injectors and a 2.9 or 2.8 pulley plus a tune.

 

you can stay with 42 with a tune for a 2.8 pulley

 

Yes... but you don't NEED 60's to run a 2.8 or 2.9... you can use the Stg2 injectors.

Yes... what he said.

I ran 2.8 & 42# injectors for 2.5 years. Perfectly. I would suggest getting it tuned to an 11.0-11.5 AFR though. Stg2 tune runs a 9.0-10.0 AFR... and that's not healthy.

 

What are you boosting? I just installed a ferw weeks ago my 2.9" pulley with my stock stage 2 42# injectors and got a tune and I am boosting 18PSI

 

18psi???

My 2.8 only hit 17psi. 18psi doesn't seem right for a 2.9"... where are you located?

 

Michigan. I'm going to be down in Cincinnati this weekend if you wanna meet up? Would be fun to chill with some other cobalt owners down there.

 

Hmmm...

There is a meet in Cinci on the 21st. My Cobalt will probably be there then. Its in a garage right now though. I'z torquing on it.

 

I took mine out of hibernation to for a little bit and did a 3rd gear pull and shes boosted 18 psi no problem. It was weird and my mods are in my sig.

 

^^Def. The tinted tails that let us hit the 18Psi Mark.

 

yes. but i'ld suggest supporting mods.

i have 2.8, 60s, tune. 11.0 AFR. and i only made 248whp because my car could not breath AT ALL!!!! that and my iat2s were hitting 150* at the top of 3rd.

 

^^ Why couldn't it breathe? No CAI or Exhaust?

 

no....anything. simply 2.8, 60s, tune. i have the ottp dual pass h/e sitting in my room waiting to be put on. its perfectly safe. brian beat the **** out of it after he tuned it. it'll start pulling timing at 140* iat2s and artificially resets the revlimiter to 6500 if the sensors decide the engine can't bring in enough air to spin that fast safely. so..its perfectly fine. just not too powerful. but i went 13.78 with it...

i have intake, header, dp, exhaust, h/e, injection, and a few other goodies waiting to be put on.

 

Well, I got my car with GMPP CAT back and GMPP exaust. Also has a CAI. Im only doing 15 psi. whats AFR? By the way, i also have 2 gallons for the radiator. i believe you guys called it option B Tank!

 

sounds stage2 to me. AFR is air:fuel ratio.

and, uhm hahahah. how exactly do you have the gmpp cat back and gmpp exhaust? lol

 

so what mods do i need to push 17 or 18 psi?

 

intake, exhaust, 2.8, 60s, tune

 

intake exhaust 2.9 and 42#ers with tune and I got 18PSI

 

clogged cat?