Have fully built LSV w/ CP 13:1 pistons. For some time now I have been thinking of putting my old Turbo on it. I have always been told turbo motors low compression but what if you did High Compression low boost?

 

Super high octane then.

And if course cams with lift but only a little overlap.

Most will tell you it's too much trouble.
Akin to turning a car into a boat.

 

I have a 13.5:1 built motor with high boost on E85.

 

good octane and a good tuner and your set, i would run e85. My personal setup im working on is a 11.8.1 compression ls vtec on e85 equipped with boost. my last setup was a stock ls b16 nippon pistons around 11.1 compression on e85 and it ran great, super responsive and made decent power!!! high comp and boost ftw, makes for a fun street car

 

This bulild is for a street car so not looking to set any records here. Just curious to know if it works safely or not. My goals I would like to see is 350-400 daily driver on pump gas.

 

Wrong

You'll want bigger cams that will bleed off compression, a properly profiled camshaft can be big, and not have "too" much overlap to create boost blow by..thats if you go with a custom profile.

If you're running E85/98 or FTW, or something like c16 or c12 you would be "OK" with low boost.

Run bigger cams to help bleed off compression, thats why people melt pistons in high compression setups and run stock cams, like GSR's or something.

 

so running e85+up to 30psi+good tuner=no problems

 

No, not necessarly..I dont know who said that.. but it takes alot more then that..

 

Big cams will lower dynamic compression bc of the overlap will let some of the compression out. Youll see that on a compression test. With high compression you wont need as much boost to make big power. Cylinder pressure is what you are generating with a mix of compression and boost. Its all relative in the end.

 

Would like to just run the car on 91 with say 9 to 10 psi maybe 15 running Skunk Pro 1 Cams. Like it was said earlier High Compression with Low boost is it not that simple.

 

I understand that big cams will lower the dynamic compression ratio. But at high engine speeds isn't the opposite true.? - The bigger cams will aid filling the cylinders with air. There for raising the effective compression ratio? I maybe wrong, it just come to mind...

 

cam selection depends on the turbo also. pro1's won't work with your run of the mill t3/t4

 

Rich Im not sure honestly. I dont understand why the results would change with a static overlap/duration regardless of rpm. - And to be clear are we talking about the same cam profile (VTEC) at both high and low rpm?

 

Either profile, I'm trying to get the effects of a large camshaft in the upper rpm range. If the camshaft is helping the engine breath in a certain area (increasing the VE) then wouldn't we consider the effective C/R to be higher in that area? I've always thought c/r and ve were linked?

Do you see what I'm getting at? If not play with the zealautoworks compression ratio and add boost to the equation and see what happens to the c/r.

 

C/R is just the volume compressed. Cam overlap and forced induction can change effective compression but simply "breathing better" does not mean effective C/R is nessecarily higher. You could run a ported head to increase engine VE and the effective C/R would not change.

 

screw you and your E85 muckman lol

 

Haha wait for the high boost results next week. So far the low boost numbers are incredible.

 

So high comp and boost go well with each others ?

 

+high octane fuel

 

is the 388whp in your Sig the current low boost numbers? mind sharing your setup or at least turbo size and motor?

 

388whp on 9psi from a GT3076R
13.5:1 CR 2.0L GSR on E85
Ill be creating a build thread once we finish the high boost tune.

 

what about e85?

 

Nice i like this thread. I also have a high compression turbo setup but waiting on money to get it tune.
Cant wait to get it dyno tune.

 

talk about the perfect street car setup, response much!! ripper vids??

 

im surprised you guys are talking overlap on a boosted high comp build..

I learned that short duration to reduce overlap is best so you dont shoot the boost out the exhaust valves..

but ill keep this thread handy to see where it goes..