[400dime]

say i got a procharged 421sbc. runnin 110 octane, 11.5:1 comp. ratio with 5-6 lbs of boost. would i make more horsepower than i would with say 8.5:1 comp. ratio with 20-22 lbs of boost or less or what? still learnin

 

[67 bird]

20-22

 

[400dime]

so i should prolly go with dish top pistons?

 

[nso123]

In theory, every atmosphere that you add (14 or so pounds of boost) you will double horsepower. I would probably look for around 9:1 and go from there.

 

[400dime]

how will i know whether to lower and raise compression?

 

[67 bird]

You lost me.

 

[Remo]

people will tell you the hi compression will spin the turbos up faster for less lag. i think thier is more to the combo than just 8.5 or 11.5 and 8 psi or 22psi. My 377twin turbo sbc is 9.25 compression and with 14psi it makes 780rwhp on 93 pump gas and a small meth kit. My 364in LS2 with a blower with 10.1 comp and 7psi made 518 rwhp. Not really apples to apples.
lots of info here http://www.ls1tech.com/forums/forced-induction-9/

Remo

 

[vance hewitt]

my opinoin is that a lower compression/boost motor will make better power ,to a point.....to low and they are sluggish for low and part throttle. to high and your tuning window gets REALLY SMALL.....top fuel cars are only like 7 to 1,and a bunch of boost.either way works but its more about the entire package........any engine that runs well is a well thought out package......dont get to caught up in the boost thing , its allways about air flow. boost numbers between 2 different engine packages mean nothing.....