whats the most compression allowable for 5psi?

**Edward-T** · 10-20-2011, 03:12 AM

just wondering how high the compression can safely be to run 5psi on a supercharger?

**FasstChevys** · 10-20-2011, 07:10 AM

Well, there's so many questions.

What fuel is going to be used?

Is it a race car, or daily driver?

Is it going to be intercooled, or not?

Let's start there.

**Edward-T** · 10-20-2011, 07:20 AM

daily driver, 93 octane,i would prefer intercooled, just wondering if my current setup is to high for a supercharger, i think i am at 10-11 on compression, more like 10 i think.

**FasstChevys** · 10-20-2011, 07:58 AM

Originally Posted by Edward-T

daily driver, 93 octane,i would prefer intercooled, just wondering if my current setup is to high for a supercharger, i think i am at 10-11 on compression, more like 10 i think.

Your compression is just fine. Personally, without an intercooler, I wouldn't go much past 5-6 psi with 93 octane. If you have an intercooler, I wouldn't go much past 8 psi. My '01 WS6 had an 8 psi ProCharger set up(intercooled), and had no issues.

If I am not mistaken, your compression ratio is 10.5:1.

I hope this helps!

**Edward-T** · 10-20-2011, 08:02 AM

well it does help, but...my car is a 2005 LQ4 with ported and polished stage 3 LS6 heads with a 64cc combustion chamber, and a TSP torquer V2 cam, 595/598 lift, so i think the compression is up there, it was 9 when it was stock, not really sure what it is now, just guessing, thanks

**FasstChevys** · 10-20-2011, 09:02 AM

Originally Posted by Edward-T

well it does help, but...my car is a 2005 LQ4 with ported and polished stage 3 LS6 heads with a 64cc combustion chamber, and a TSP torquer V2 cam, 595/598 lift, so i think the compression is up there, it was 9 when it was stock, not really sure what it is now, just guessing, thanks

Haha, touche! That is a bit different than a stock LS1!

Either way, if it runs currently on 93 octane, I'm still confident with my above statements.

**Edward-T** · 10-20-2011, 09:07 AM

that sounds good man, thanks. so i should be good to run 5 psi then? looking for that magical 500 whp mark, currently at 442, and i dont want to do nitrous or a turbo, just dont like either really.

**FasstChevys** · 10-20-2011, 10:05 AM

Originally Posted by Edward-T

that sounds good man, thanks. so i should be good to run 5 psi then? looking for that magical 500 whp mark, currently at 442, and i dont want to do nitrous or a turbo, just dont like either really.

WOW - dude, if you run 5 psi, without an intercooler, you'll be WELL north of 500 to the wheel if you're already at 442!

If you roll with 8 psi and an intercooler, I bet you'd be close to or above 600 whp.

**stevenm357** · 10-20-2011, 10:26 AM

What king of super charger are you going with then 5 psi should put you well into mid 5's with that setup.

**Edward-T** · 10-20-2011, 10:33 AM

Not sure yet, wanted to make sure I could run a supercharger with my current heads and not blow it up, I still have the factory 317 heads as well, I hear a lot of good talk about procharger but only if I can safely do it.

**stevenm357** · 10-20-2011, 10:40 AM

They supercharge ls7's your cam selection may not be ideal but should t allow too much. Blow by your 112 lsa right the torqued v2 in my friends car is.

**FasstChevys** · 10-20-2011, 11:00 AM

Originally Posted by Edward-T

Not sure yet, wanted to make sure I could run a supercharger with my current heads and not blow it up, I still have the factory 317 heads as well, I hear a lot of good talk about procharger but only if I can safely do it.

My opinion would be to go with a ProCharger. But, of course, that's always up to the purchaser!

**Edward-T** · 10-20-2011, 11:37 AM

Yes its a 112 lsa, and I know nothing about superchargers so your advice and help is greatly appreciated.

**FasstChevys** · 10-21-2011, 06:36 AM

Also, one thing that I always forget! If you install an Alky injection kit along with your supercharger, you can push boost a little more safely since it drastically lowers your AICT(air intake charge temp), which will prevent detonation.

**Edward-T** · 10-21-2011, 06:46 AM

cool, thanks. i am just thinking about now, still afraid of blowing it up if i go s/c or turbo, would thicker head gaskets help any?

**FasstChevys** · 10-21-2011, 06:50 AM

Originally Posted by Edward-T

cool, thanks. i am just thinking about now, still afraid of blowing it up if i go s/c or turbo, would thicker head gaskets help any?

I suppose it would lower your compression a touch. To be honest, if you don't have a good tune, and maintain it properly, the thicker head gaskets aren't going to matter.

**Edward-T** · 10-21-2011, 06:56 AM

yea, make sense man, thanks

**35th-ANV-SS** · 10-21-2011, 10:27 AM

At 8psi with a completely stock motor (cam/heads) I made 501rwhp with the Procharger, intercooler, and AlkyControl methanol kit. I am going to suggest you build the car up first (suspension, transmission, rear end) before adding power like that.

**Edward-T** · 10-21-2011, 12:50 PM

Yea your right 35th, already got most of the suspension replaced with umi stuff, still need shocks and sway bars replaced.I won't get into s/c seriously till spring time I guess.may go with a differant cam and still need to do 42# injectors at least, fuel pump was already replaced with a walbro 255 ( I think that's what he said-have to check my paperwok to verify). I like the power now but I think I'm addicted-gotta have a little more.