I am looking to upgrade my 2006 Cobalt SS SC and I am looking for suggestions on what size supercharger pulley would get the best performance while keeping the car as my daily driver. Any suggestions?

 

No smaller than a 2.9 with LUCAS flowmatched 42 lb injectors, and a good tune.

BTW you are going to get a bunch of prople telling you to use the serch button. Tell them to F**K OFF!!! LOL.

 

If you don't care about warranty I would get 42# injectors, a hub, nates 2.9" polished pulley, and get it tuned. Basically the gm stage 2 but with a little more power. If you wan't warranty, get gm stage 2, www.crateenginedepot.com should have it the cheapest. You can still put nates 2.9" pulley on it (nherbst) for some more boost.

I was down in West Chester a month or so ago and saw a black ss/sc, what color is yours? Ever see a silver ss/sc down that way?

 

generally, a 2.7" pulley with 60lb/hr injectors is considered safe and reliable.
i use a 2.9" pulley with 42lb/hr injectors.. and i was running high 13's. since then i've gotten alot of bolt-ons, and have gotten down to low 13's on stock tires.
it all depends on how fast you are looking to go.
if you want 12's.. i suggest you look into the twinscrew supercharger swap, or the hahn turbo system.

 

I have a 2.7 with 60's and its fine as a daily driver...just make sure u get a good and safe tune, thats the most important thing

 

are you compeletly stock as of now?

 

you mean like:

 

why 2.80 pulley is not ok with 42 lbs injectors i mean how much diference are betewn a 2.8 and a 2.9 is just funny i am sorry if this break the thread!!!

 

1psi.....

 

that 1 psi can cause damaged to the egine? lol

 

It isn't the boost its the injector flow rate. The 42# will go above 100% duty cycle, they already do on a 2.9. If they do that they go static, can't control flow, not good. Now you understand?

 

the psi itself? No, the fact that you will be maxing your injectors out yes

 

yes. without enough fuel. BOOM

 

aaah ok!

 

you can run a 2.8 with 42's IF you know what you're doing. most people on here don't have a clue when you get technical enough to explain the "why and how" so it's safer to say no.

 

you're right. but alot of us dont want to explain why and how to someone who dosent understand it anyway.
example: you didnt explain it

 

please explain, bc at 6800 my injectors were maxed on a 2.9 and that is at a a/f 11.5. They only thing i could think on a 2.8 would be shifting at 6500 before they go static

 

Get GM stage II!

 

I have the 2.8" pulley, 42# injectors, and a custome tune and I dont knock nor has my engine blown up. A lot of us guys in AZ are running the same setup and have never blown anything in our engines. Its the 60# guys that blown there engines up.

I saw 2.8" and 42# and custome tune.

 

but you have to expell that extra pound of boost through the boost bypass valve, using hptuners.

this way, you still get the low end torque of the smaller pulley, but you drop of the pressure up top, and maintain safe a/f ratios.

 

there is a trick you can do with them. it's called water injection.

thats the easy way of doing it. my duty cycle with the 42/2.8 deal hovers around 85-88% what people are stuck on is duty cycle. it is a calculation. not an exact. what is exact is the Msec. 20.0 msec is static.

i have tuned a 2.85 car, where the duty cycle was maxed at 89%. then a 2.9 car that was starting at 110%. keep in mind, this is a calculation. which is not correct for 07 cars anyways, which is what i tune 99% of the time.
at 6500 on the stock gm tune, the injectors went static with the 2.8. how do i know this? wideband showed this cute little spike. it was running a solid 11.2 all the way up. till this point, then it just sky rocketed to 12.5.

with the water injection, i was able to pull enough fuel out of the car to keep the injectors in check. it runs 11.3 from 2k all the way to 7200. no dips, spikes or anything stupid in the middle. we can't give all of our secrets away, so i won't go into detail about this. knowing this little bit of info, in short, it can be done with supporting mods. if you're not wanting to do water injection. get 60's.

 

dosent power drop off before 7,200rpm?

 

depends on how you set it up. mine does not. but i don't take it to 7200 on a regular basis. i might shift at 6800 at most when im runnin at the track. or i get picked on.

 

Well I have a question, what is required to use a 2.9 pulley? And whats required to run a 2.8? I already have the stg 2.

 

Tunes is going to be required if you want to do it right. Thats what I did when I went from 3" to 2.8" You dont need anything else it will bolt up to the GM hub (if that what you got) and the belt will fit.