higher compression
Drifting
Joined: Jul 2003
Posts: 1,796
Likes: 1
From: Annandale VA
Swapping out internals like pistons is expensive, and not worth it unless you are also contemplating other mods.
First, you can raise your compression much more easily by milling the heads .030", and/or installing a thinner Cometic head gasket. However, the higher compression will just result in possible preignition/pinging, unless you get a computer tune, and retard your timing. Retarding the timing will reduce your power, thus eliminating any gains from the higher compression. Yes, you can address this issue by running race gas, or with an additive such as Torco, but neither is very suitable for the street.
You could also run an alcohol/water injection system, fed by a tank mounted in the rear of the car. Such a system is currently being touted on this forum in a current thread.
Raising compression is usually done in conjunction with an aftermarket cam with longer duration. The cam timing has the effect of lowering the dynamic compression, so static is raised to compensate.
Raising compression by itself is not a good idea. Doing it with aftermarket pistons is a really bad idea.
First, you can raise your compression much more easily by milling the heads .030", and/or installing a thinner Cometic head gasket. However, the higher compression will just result in possible preignition/pinging, unless you get a computer tune, and retard your timing. Retarding the timing will reduce your power, thus eliminating any gains from the higher compression. Yes, you can address this issue by running race gas, or with an additive such as Torco, but neither is very suitable for the street.
You could also run an alcohol/water injection system, fed by a tank mounted in the rear of the car. Such a system is currently being touted on this forum in a current thread.
Raising compression is usually done in conjunction with an aftermarket cam with longer duration. The cam timing has the effect of lowering the dynamic compression, so static is raised to compensate.
Raising compression by itself is not a good idea. Doing it with aftermarket pistons is a really bad idea.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
When I put in my G5x3 cam I put in Cometic .040 gaskets to raise compresion to about 11.4 with DCR of about 8.2 (I forget the exact DCR number). I did this to keep my low end torque close to the same in my daily driver. I've also been told that the thin gasket reduces quench area and allows me to run more timing without pinging, which is true because I can run quite a bit without KR.
It worked. I actually gained a little low end torque below 4k even with the big cam. My torque curve remained basically the same.
Here's my write up and dyno sheets.
http://forums.corvetteforum.com/show....php?t=1769681
It worked. I actually gained a little low end torque below 4k even with the big cam. My torque curve remained basically the same.
Here's my write up and dyno sheets.
http://forums.corvetteforum.com/show....php?t=1769681
