With HPTs you can by-pass the SC boost after 4,000rpms. So under 4,000rpms, you pretty much have to deal with what you get.

Smoothflowpulleys.com can make you a SC pulley up to 3.8".

 

you will definitely need air to air if you have the turbo up front. Only reason I get away without it is because my turbo is in the back and I have the ottp h/e, dual pass, option b, phenolic spacer and meth injection.

 

cool. thanks for the input guys

 

If your running a 2.2 pcm, you will not have those boost by-pass controls that the LSJ has.

The original Twincharged LSJ never by-passed the SC and used the SC and turbo in a "compounded" setup.

 

thats the way i was looking to run it. there was another member who was talking about by-passing. i have the lsj not the 2.2

 

The 2.2 ECU has those options in the tune not saying they work though.

Can you get enough cooling for that? The air to air is going to take the room of the second h/e. I can see heat soak being more of an issue.

 

Compounding the boost works a lot different then a by-pass setup.

https://www.cobaltss.net/forums/adva...ormula-132146/

Basically you can run less boost from the turbo, less boost from the SC and still make a lot of total boost. Less boost = less heat. But heat soak should be of concern.

I am not trying to talk anyone into doing it one way or another. I am just trying to provide enough info for people to make an informed decision.

 

I was just expressing the heat soak concern since the secondary H/E cant be used if an air-air is so he goes through all the senarios first.

 

So if I don't bypass I could in theory run the k04 compounded to hit my 400 hp mark? Just at an insane 28-30 psi? Tho at that point I would say I'll suck it up and deal with 325 hp or so, since I'm running a 10.5-1 compression 2.4 bottom end with a very restrictive 2.2 head, anything over 325 I'd just be asking for problems

 

if ur going through all this trouble y not just build the engine up to support more. thats what i'm gonna do before i even start accumulating parts for the twin charge

 

Doesn't the problem with heat come from compressing air, correct? I would assume the higher the volume of air you compress the more heat that gets created. Even with less boost from the SC and TC isn't air still being compressed the same? If that is the case then since so much money is being spent wouldn't it be worth the extra cooling just to have piece of mind your AIT2 temps aren't getting too hot?

 

I can handle 400 hp with the 2.4 block only Gotta worry about high compression, I'll be fine if I dial it back to 325 for dd and a 400 hp tune for track use