What does GM generally give you when you get a stage 2 kit..as far as size of pulley & injectors? If you don't specify what you want of course.

 

GM stage 2 is 42# injectors and a 79mm pulley

 

How do I get a smaller pulley, if so what kind of power difference can I see? Also how much HP can 42# injectors take.

 

You are going to get different replies about what 42s can handle and all that. Most people agree that you can safely run a 2.9 pulley on 42s with the stage 2 tune. Some people go smaller but that creates more heat and it maxes out the injectors but its up to you. You wont see a huge difference from stage 2 to 2.9...it hits boost a lil sooner and sounds a bit better. I read where every .1 inch you drop you gain 1 psi of boost.

 

i don't think that's right, because you would see over 3 psi of boost more with a 2.9 in that case.

and boost doesn't necesarily = power. someone running less boost can be making more power. too many people put too much emphasis on boost #'s.

 

Well, I checked my standard pulley is a 79mm which is a 3.1" pulley...a little big. Still havent' gotten an answer on what kind of horsepower 42# injectors can take. I am pushing 240+ to the wheels...wanna make sure nothing is happening that I don't know about.

 

How would you see a 3 psi increase? The stage 2 pulley is like 3.03 correct and you drop to a 2.9....thats only 1 psi.

 

I don't car about PSI guys I am pushing 17psi. I want to know what the 42# injectors can take as far as HP goes.

 

I think once you hit 250hp its time for bigger injectors.

 

The 42's can handle all the HP the engine can, it's that they can't flow properly after 2.9" and smaller pullies as they need to push more fuel through at high RPMs than the 42 can handle. GM uses the stage 3 pulley and says that is the max for the 42s. The HP limit is the pistons, rings and head more than the injectors. The 42s can spray enough fuel to go down to a 2.9 pulley which adds boost which adds some power and tonnes of heat. I hope that answers it....

 

it's 3.06 actually.

either way, i was wrong. i'm bad at math, even with a calculator

 

The man wanted a horsepower number, so thats what I gave him.

 

Lol my bad i thought it was 3.03. But i just read what i was saying. Im not sure if its true or not.

 

My next ? is what is a good header? How much HP would it add, how much it would cost? About the pulley's again, can I just go to GM for a smaller one?

 

No you cannot just goto GM. Well, theres stage 3 but we wont go there, its a pain in the **** to do for a few extra horses and no A/C. www.smoothflowpulleys.com We havent seen a blown motor with the stage 2 injectors on any pulley equal to or larger than a 2.9, unless some crazy **** happened that has nothing to do with the choice of pulley/injectors/tune.

 

YES YOU CAN GET A SMALLER PULLEY FROM GM. You don't have to buy the entire stage 3 kit, just get the pulley. But the pulleis from Smoothflow will be lighter and you can get smaller ones than the GM stage 3 pulley.

 

What is a good product to clean up oil grease all over an engine bay?

 

You're pushing 17psi with the stage 2 pulley? You're boost gauge is broken.

How much hp can it take? I have no idea what you're talking about...the more air you add the more fuel you need; and as far as I know the smallest pulley you can run on the stage 2 tune without going static is around 2.9" past that you need to tune and add bigger injectors.

 

Yep or your cat is starting to plug up. I'm running a stage 3 pulley (2.99) and haven't seen over 16.5 psi.

 

I have run at 120 Kpa or 17.4 psi since my Stage II upgrade (and AEM cai), with 30 000Kms on the car. And my car boosted 85 Kpa or 12.3 psi right from stock day 1 (12 kms). According to the boost gauge anyway. It is just an electrical gauge pulling info from the computer.
And my cat is fine.

 

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if you get exhaust work that # will drop down.

 

Those gauges (like the interceptor) don't have accurate boost measurements. You need a mechanical gauge.

 

Meaning i'll lose some boost pressure?

Yea, thats why i mentioned the part about it probably not being accurate. It just reads from the computer.

 

yes. bigger exhaust evacuates more of the air from the cylinders, so theres less time for it to back up in the engine meaning less boost psi. It's not a bad thing, it just means your engine is running more efficiently.

As far as injectors and pulleys go, ive said it before; my IDC was 117% with 2.9 on 42s. Since has been retuned to a safer 100%. If you know someone that can tune worth a ****, put a 2.8-2.9 on it and do some cooling mods and you'll be fine. Just have them lean it out a bit for you, as the Stage 2 is rich as hell anyway.

 

yes. but just because the boost is lower doesn't mean it's bad, or making less power. the engine will run more efficiently.