ok my ss/sc is putting 220 to the front wheels with a injen intake and a 3.10 at 15 psi now the stock injectors can go up to 235whp so how close would i be if i put a 2.80 pully on now it would be about 17 -18 psi do you think it well work with out running to lean and if so if i got the gm stage 1 which is a fuel injectors and a ecu updata that would be all right with the 2.80 pully?

 

I wouldnt go any smaller than the 3.1 with stock injectors/tune. How small you can go with Stage 1/2 tune is up for debate. Most would say 2.8 or 2.9. It also depends on where you are and your climate. I think the warmer climate areas are ok with the 2.8 otherwise, stick with the 2.9 to be on the safe side.

 

I will second that. I ran a 2.8 for a wile on gm 2 and had lots of p103 codes come up. But it is still debatable but to be on the safe side I would go with the TAG stage 2 upgrade GB. It gives you 60 lb injectors and a tune to fit the 2.8 so you do not hurt anything. In any case you should stay with the 2.9 with the GM stage 2.

 

Exactly that's a huge NO-GO on the 2.8 with stock injectors. Like GeoChevyCobalt said. TAG has a nice group buy on a 2.79" pulley w/60lb. injectors. That's a better setup. Here is the link to the group buy.

https://www.cobaltss.net/forums/show...=tag+group+buy

 

had my 2.8 on for months now with gm stage 2 tune/kit..not one code or issue. But i wouldnt dare on stock injectors either

 

O.k I think it time to clear this once and for all. Its not the size of the pulley its How much boost you are actually making?

Let me explain:

I make 16-17 PSI MAX with my 2.8" pulley this is in the winter time in Ottawa Canada, In the summer I never go past 16PSI even at over 6500rpm. I have 42# injectors which are quite capable of handling 16-17PSI but not anymore boost then this.
But this is me and where I live.

3.3" - 3" = 11-13 PSI stock injectors are o.k here.
2.9"- 2.8" = 14-17PSI 42# Injectors are o.k here.
2.7"- 2.5" = 18-21PSI 60# Injectors are o.k here.

So check how much boost your making, use this little chart as a approx boost reading. It will differ from regions and climate.

 

i know your intentions are good and you are asking a question so you can learn....... but..... plz plz plz plz PLZ do quite a bit of research on this site. you know the basics, but you just dont quite have it down.

no, you can not run a 2.8" pulley on a stock cobalt. it's not about the horsepower either, it's about the boost you are running (as denny explained). running lean with the stage 1 kit and a 2.8" is debatable. it depends where you live and how concerned you are about safety. btw, you cannot just run the stage 1. you need a stage 2 belt as well to cope with the smaller pulley.

as i said, just be patient and do some research on the site. you'll find out much more this way.

 

i double dare you too put a 2.8" pulley on stock injectors lol

 

i double dog dare you!



and plz film .... that way you can show the dealership what happened (psst. posting it up for laughs would be a good secondary objective as well )

edit: im j/k man. not meaning to get on your case by any means.

 

Mines_Better has an 06 w/ 2.85 and tensioner
nothing else, runs great with 2 step colder plugs
i think the amount of boost and climate make the difference

 

errr. i really give my best wishes to his car. if he has no probs, he is running on a miracle

 

^^ lol lets all hope his car runs fine

 

Tripple dog dare you!

Note: Just kidding

 

anbody with the 2.8 pulley on have to change the belt tensioner when they put it on??? I want to install my 2.8 pulley when I get my stage 2 kit put on next tuesday.

 

I know some guys said that PB 2.8 pulley looks exactly like the stage 2 pulley that comes with the GM kit. Does anyone know of a 2.9 pulley that looks exactly like the stage 2 pulley besides the measurment number?

 

running the 2 step colder plugs is the ONLY reason the guy hasnt blown a piston, 2 step colder plugs and running like 93 octane would be a huge difference in fighting off knock, im sure with 2.85 on the stock tune hes lean as hell, but might not see any knock with the plugs and high octane.... its silly though. i ran a 3 \' and 1 step colder plugs for quite awhile. no issues at all there.

 

I don't understand why anyone would risk "leaning" a finely engineered 2.0, to save a few dollars. It's basic physics: if you add more air, you gotta add more fuel .....or KAPUT!.
The ECU (or whatever people call them these days) can only compensate for small variations in the mixture either way. It's all or nothing in my oppinion.

 

mother of god.....after the huge discussions about 2.8s being high IDC for the 42lbs injectors people are actually running 2.8s on STOCK injectors?!?!?!?!


wow

just wow.

 

sunday im throwing my 2.8 pulley on my stage 2 kit for the track and the stock stage 2 pulley goes back on when i leave the track..i wouldnt run the 2.8 all the time..i have 1 step colder plugs