I have been running Stage II 5.3L heads for a while. And have been researching a Procharger. Could I get away with running any amount of boost?

 

not on pump gas. at least, not enough for it to be worth your trouble(1 or 2 psi).

 

depends on your cylinder pressure. what hp are you making right now with those heads? if under 500hp id think you have that much room to grow..

it would certainly be more cost effective to sell your current heads and put a set of stock 6.0's on and then the boost. you will be able to make just as much power.

 

I didn't really want to deal with swapping heads. But I know FI likes lower CR.

I am only @ 360 rwhp. I would like to get about 450 rwhp on FI. And maybe let N20 take me the rest of the way to 500.

 

i dont see any problem at all with going to 450rw on 95 octane and boost and your set up.

 

We have that shitty 91 out here in Cali.

Eventually I may swap the heads out.

 

I think its playing with fire.....

I had some MTI stage 2 heads that were milled to 10.6:1 compression.....I was running 6psi, stock motor, with a 214/218 .540/.550 114lsa cam.....

I blew the head gasket on #7 w/this setup on pump gas......

I then changed the heads to TEA S2 5.7L 73cc chambers to lower comp to around 9.3:1, I was then seeing 4psi total, making around 460rwhp through the TH400....my motor was hurt I think from the head gasket deal, it dripped oil out of the breather valves

 

Thanks for the info guys. I went ahead and also called ATI.

They say I shouldn't have a problem with running 4-5 psi on 11:1 CR. Just so long I don't have any detonantion.

In fact, they told me its not the boost or CR which is the problem. Its detonation. Just so long there is enough fuel to support the power. Truth?

Oh and anything under 5 psi with the P-1SC-1 is CARB legal.

 

Everone is trying to tell you something here! Sure ATI wii tell you its ok. Take advice from the guys here that have gone through this ****. It gets very expensive and alot of downtime. You will hate your car for a while, think about selling it, and then wonder why you didn't take what we said seriously. Your choice, just my 02. Angelo

 

Thats 100% true but detonation is just what you will get unless you put high octane fuel in or use alcohol injection.

 

Well, that is why I am here. Asking questions first. I don't want a headache. This is my daily driver so it has to be somewhat reliable.

Guess I will have to plan on switching them out. Should stock heads get me where I want to be?

 

Don't mess with High CR and Boost...its not worth it. I blew up my motor running 10lbs of boost with an ATI Procharger, and I know a lot of people that have lost their motors 10-10.5:1 CR later on with 6-8lbs of boost. The stock PCM just can't keep the AFR perfect all the time..and it usually only takes once or twice with stock Hyperutetic Pistons...the Ring Lans crack like wafer crackers in big chunks....don't screw with it dude...a daily driver is not a daily driver with a blown motor...it becomes a project...listen to those that have blazed the path before you....I wouldn't listen to ATI for anything when it comes to the design of their LSx kits...they make good head units though.

 

Thanks, I was hoping to get away with no more than 5#. Spent some good money on the heads. I do have access to some stock heads.

 

Its a no brainer than dude. Sell the 5.3liter heads and send your stock heads to Richard at WCCH. Have them opened up to 73cc's and have him install in a set of REV 1116 Valve Springs you will need them for a boosted motor. You will be able to run 10lbs of boost all day. It won't cost you an arm and a leg to have the chambers opened up either.

 

According to ATI, to stay smog legal I need to stay under 5#. Can I be @ 450 rwhp with 5# and stock heads? Guess I could always switch to the 7# pulley. Then back to the 5# at smog time. As to how they know its beyond me.

I plan on dual springs to handle to cam. Any reason to get larger valves with FI?

Thanks again.

 

ATI is full of ****...the only thing you really need if they check is the CARB #...which is on there P1, but I have heard that they are seeking one for the D1...although..the P1 and the D1 look very similar if you get my drift.

For what it is worth..force induction does not rely on big cams and fully ported heads as much as NA.
I made 610/545 rwhp/rwtq @6200 rpms (I ran out of injector or fuel pump) using non ported LS6 heads (changed the valve springs only) and a Comp Xer 224 Cam. I think you just need to have your stock heads chambers opened up and some valve springs. You can probably make 450rwhp with 5-6lbs of boost because you will be able to make up for the CR drop with timing.

 

Thanks, you guys talked me into it. I'll take those stock heads, throw on dual-springs, Ti retainers. And get them on the engine. Then I should be able to run 5# or 7#

I may have a buyer on my heads already.

Hope I am not disappointed, since I have already run N20.

 

Well the kit is ordered, but now ATI says the only Supercharger with a CARB # is the 4# FMU kit.

Can anyone verify if the 5# or the 7# has a CARB # on it?