snowboardgod869

im building a 350 bored 40 over i have Keith black forged pistons stock 350 rods and crank and a splayed 4 bolt main i have some 416 heads with 64 cc combustion chambers which 62cc combustion chambers put me a 10.6 compression my question is how much compression with what supercharger will add i was thinking of picking up some afr heads with maybe 76cc heads to bring my compression down to maybe 9 to 1 and have the super charger but how much compression will it increase with it?

daverr

iTrader: (1)

forced induction does not increase compression ratio.

blackbmagic

While it doesn't add to the acctually dynamic compression ratio, It does increase internal pressure. This is why generally low dynamic compression ration is used with a forced induction application, it allows for a higher pressure without knocking. The higher the compression the more pressure in the combustion chamber.

You do not HAVE to lower you compression although the afr heads might flow better. Just make sure you have the coolest possible intake charge, have the correct cam, and are running the right octane. 10.6:1 is fairly high and you should venture lower than 93oct.

Just remember your engines compression ratio stays the same when adding forced induction, but the pressure in the combustion chamber increases.
ie.
The combustion chamber pressure of 10.6:1CR and 10lbs of boost pressure > 9.1:1 and 10lbs of boost pressure

The real question comes down to your setup and how much boost you want to effectively produce without detonation.

snowboardgod869

so what is a good compression ratio to run with what size super charger if i am running stock rods and a crank but i have forged pistons and what kind of camshaft but i would also like to get my hp over 500 if possible

blackbmagic

Well I wouldn't recommend doing anything near 500+ with stock rods first off. You need to do a little bit more research about super chargers and forced induction before asking about sizes and specs. You need to have a budget and a price range as well as time range and mechanical ability.

As for the cam, you should talk to your dealer or if you want to go with Comp Cams they have some pretty accurate software called cam-quest to help you find the specs of the cam that will best suit your application.

It all comes down to how your motor is built, before you can start asking questions about what size pulleys and how much boost.

I myself would stay below 9:1 for a boosted application. Maybe even as low as 7.5:1.

what do you mean by that?

I'm sure there are others that can get more specific for you. Search the archives for other users builds and projects for info. Make sure you can not find your info before you ask to many questions. Value peoples help and only ask questions if you need to.