Supercharger/Compression Ratio
- Thread starter Drew8509
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That really depends on a lot of things. How much boost do you have planned? Do you have aluminum heads? Pump gas? Cam size? Forged pistons? Street or strip?
The simple answer is yes, you can run boost.
The complex part comes in under what you are trying to do with your engine. You are really searching for an ideal "effective compression ratio" to increase your performance.
Higher compression = less maximum boost
Lower compression = more maximum boost
Serious competion turbo guys go low, like 7.5 to 1 low, so that they can really run high levels of boost. This also allows them to pack more air in the cylinder than a high compression low boost engine because they can compress more air.
The rest of what is matched above is dialed in to match your combination. There are lots of late model LS1 guys running a supercharger with their already high compression ratios and loving it, they just don't reach the potential that the supercharger (or turbo) can provide when they are limited by the amount of boost they can run.
The complex part comes in under what you are trying to do with your engine. You are really searching for an ideal "effective compression ratio" to increase your performance.
Higher compression = less maximum boost
Lower compression = more maximum boost
Serious competion turbo guys go low, like 7.5 to 1 low, so that they can really run high levels of boost. This also allows them to pack more air in the cylinder than a high compression low boost engine because they can compress more air.
The rest of what is matched above is dialed in to match your combination. There are lots of late model LS1 guys running a supercharger with their already high compression ratios and loving it, they just don't reach the potential that the supercharger (or turbo) can provide when they are limited by the amount of boost they can run.
it also depends on if you have a carb or EFI. EFI will "allow" more cylinder pressure and allow more boost. at your ratio (mines the same) you can run about 5-6psi and 8-12 with a good intercooler. but there are many things that will vary that.
If the internals are forged.. and you're not going to run high boost... 6-9 PSI.. I say it's okay... but be prepared to possibly replace things once you go too high.. In my opinion.. O-ringed head gaskets is a must... Forged crank is a must..
Good Luck..
I rebuilt a small block already..
Good Luck..
I rebuilt a small block already..
An 8.5:1 compression ratio is ideal for a super-charged motor.
9.6:1 shouldn't be a problem, just don't go crazy with the boost.
9.6:1 shouldn't be a problem, just don't go crazy with the boost.
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