kmn5

Hi all,
I know some of your guys have gone turbo without the thicker head gasket to drop the compression.
How much HP were you able to get? and how much boost will the engine handle reliabley before a thicker head gasket is needed.
I'm also considering using an Aquamist system to help insure against detonation.

Regards
Ken

JBrady

I don't want to insult anyone here in any way BUT using a thicker gasket to lower compression is NOT the best way. The factory designs the combustion chamber (head forms top, piston forms bottom) to have specific "quelch" or "squish" areas. This is where the piston and head almost touch and fuction to create swirl and capture the compressed mixture close to the spark plug for best ignition and burn. Using a thicker gasked does drop the static compression but at the expense of loosing this function. In some applications the effect can even induce detonation as the previous "squish" area becomes a detonation prone area.

Power wise? I think many are making over 400rwhp with stock assemblies.

Options: unshrouding valves and slight material remove from piston surface in areas NOT affected by squish.

SC300T

Above 8-9psi its a tradeoff. You'll have to sacrifice a little timing in order to get the boost above this level without detonation. If you have a standalone ECU you'll be much better off, the stock ECU doesn't hold the timing anywhere near ideal across the band. It's advanced in the 4500rpm area and retarded up top. A standalone ECU would let you run more consistent timing and get you to around 12psi without detonation on relatively mild timing.

Without the head gasket or getting inside the engine, you could probably hit 450rwhp on pump gas with ideal tuning and an aftermarket ECU, good intake and exhaust setup. A few of us on the board have exceeded 400rwhp on pump gas on stock compression.

kmn5

What aftermarket standalone ecu do you guys run?
Any diff between the brands? Elcrtomotive, PowerFC, etc...
and how much did you guys pay?

thanks
Ken

SC300T

I'm trying the AEM. Ethan has the Speedpro. Clint is going with a Motec M48, Jeff has a Haltech. All have their benefits. Ethan swears by the Speedpro's auto mapping function. His Wideband 02 can populate the fuel tables for him. Jeff has Lance in Miami. Lance has done many Haltech's so tuning is a breeze. Clint is a maniac, the Motec has quite a following in the racing realm. I'm doing the AEM, apparently Larry at SP has started using and tuning the AEM. I'd use whatever the install shop is comfortable with.