8 to 1 compression and 32 timing, with 1.5 pulled out for every pound of boost. 8 lbs of boost would knock the timing back to 20.
Wow, ok. That's some nice timing for a turbo motor. I wonder if a cam with a late closing intake valve could be used on a higher comp. motor to bleed off some compression. Although most cams with late intake closing are made for high compression motors and have huge duration (lope) and lots of overlap. And overlap is definitely not wanted on a turbo motor, at least a street turbo motor where the exhaust manifold pressure at the valve will be higher than the intake manifold pressure at the valve. And then if one would spend money on a cutsom grind cam they might as well build the motor that would be best for it too...
Put in a bigger cam and that will help. If you need to drop the compression, just buy a thick set of Cometic gaskets. OR buy a set when you blow out the stock ones. Run a Boost Cooler setup. Will be money well spent for a street car. You can get a controller that runs "washer fluid" progressively off the amount of boost.
Hey Nitro71455, would you mind sharing your static compression ratio with that 12psi on pump gas? Are you also running a pretty big cam? You have more flexibility with a supercharger vs turbo since you don't have to worry about the exhaust backpressure issue.
Are these any that TA carries? I saw their multi-layer ones that go up to 0.054". Then there are ones that require o-ringing the block that go up to 0.125". Based on a 430, and a stock gasket thickness of 0.020", moving up to a 0.054" gasket would drop compression from 10.25 to ~10.18. And a 0.125" gasket to ~10.05. That doesn't seem like a worth-while drop to replace headgaskets. Unless like you say, the stock ones are going to squish out without much effort. I won't get to crazy on this setup. To get serious, eventually I'll have to build up a speciatly 455 with extra head bolts using the Stg 2 SEs.
I'm currently sitting at 9 to 1 compression wise thinks to the .130 thick Commetics Head Gaskets. I also found a good progressive Alky kit was worth it's weight in gold. I'm still running a small cam (crower) that's not real boost friendly. Intake is .518 on a 230 duration Ex .519 on 236 duration Lobe seperation is 112 I run my timing at 30 to 31 degrees total and have for the last 3 years. --Rich
