What do you guys think about lowering the stock compression with thicker headgaskets? I have been looking at dropping static compression with a thicker gasket but keeping stock internals and running a little more boost. Any feedback?

 

I know of a guy doing it on his Turbo IS300. I forget how much boost he's running but he's putting down something like 5xx at the wheels, I'll have to ask and find out. I think it should work fine.

 

I have access to a c and c manufacturer who can make me copper gaskets. AT .025" thickness the stock gasket yields 10.3:1 static compression. The following thicknesses of gasket give the following compression ratios

.025 = 10.3
.050 = 9.71
.070 = 9.26
.086 = 8.93

I am looking at the .086 gasket thickness to get me to about 9:1 for the turbo set-up. I am sure the car will run a little slugish off boost but should be great when she hits. It would allow me to run a bit more timing too. I wonder with lower static compression and more boost if the rods will still only handle around 400 rwhp?
Any ideas?

 

Copper is generaly not what you want to use ona street engine for a variety of reasons.....we shyed away from it with the gaskets we have being wrapped up becuase the pros did nto outweight the cons.

Ours will be a double layer metal gasket - I ahev the numbers someplace in my notes as to what the thicknesses equaled out to , so i will look. IIRC we did 2 different thicknesses.

ETA last I checked was about 10 days.

 

Z1, what are you guys offering? PM me if you'd like.

 

I think adding a metal gasket would not be a good idea just to increase boost..

g356gear:

400rwhp can be accomplished without adding a gasket pretty safely

 

I was wanting to decrease static compression in our engine to make it more boost friendly and a little longevity to the motors life.

 

What is the problem with copper on a steet engine ? I am curious.

 

Copper head gaskets have a tendency to leak coolant. You would also need to go back and retorque the head bolts after the motor goes through a heat cycle.

Give Cometic Gaskets a call. If they don'y already have them, they can have them made. Custom thickness also.
www.cometic.com
or, (440) 354-0777

 

Hey g356gear, your not going to want to run more timing. More timing is not always better, properly tuned timing for a given amount of a/f mixture is what you want. You wouldn't want the flame front hiting the piston before the internals are at a point where they make their most torque.

With all the trouble it would be to change the head gasket your not going to remove the weak link from the motor. Lower compression is going to hurt your performance, you cannot run more boost on stock internals to make up for it. You want to run the highest possible compression that your fuel can withstand. If your getting predetonation then I would be concerned, but if not I would just wait to rebuild the entire motor if I were you.

 

The reason I ask is because I am installing my Greddy kit on my spare motor that is out of the car. Now is the time to do the gaskets if I am going to do it. That's why I posted.....I just wanted some feedback on what I am proposing. Thanks for the input.

 

Spare motor? What are you waiting for? Build that block for boost and forget about it! I would build a solid block and drop it in. Shoot for 9:1 - 8.8:1 comp, that should be good for ~22 psi on 93 octane.

 

Unfortunately after buying the greddy tt kit , intercooler, e-o1, os giken clutch, fjo wideband, greddy gauges, j&s safeguard, etc. .... the credit card has to take a rest. I can't drop another 3 grand on the project. I have to be able to drive the car on a daily basis and retain some civility. I looked at the situation and thought the gaskets might be a good and relatively cost effective way to increase the longevity of the motor.

I have talked to the manufacturer and they do make gaskets for turbo cars out of copper material. They do say you need a sealant like a copper spray or the like on the gasket. But this is what I usually do on my motors anyway. Any other opinions on the copper gaskets??