9:1 or 8:4:1

[graphic]

which compression should i go with???

and for that matter anybody ever heard anything bad about weisco pistons???

i am running a stock h22a4 w/ a f-max turbo kit right now...

and i am getting ready to build up my bottom end...

my goal is to run 12-15 psi on the street and 15-20 psi on the track

[mugenrsx]

Either of the pistons would be fine. With the 8:4:1 you would need to boost higher because of the lack of compression to make power. You do know you have to get new sleeves if you get forged pistons in a H22A right?

[graphic]

yes i know.....

how much boost will i have to make to equal the boost of 9:1 compression????

in other words if at 10 psi with 9:1 i make 280whp,

how much boost will i need to make 280whp @ 8:4:1

[skibbs]

Originally posted by graphic
yes i know.....

how much boost will i have to make to equal the boost of 9:1 compression????

in other words if at 10 psi with 9:1 i make 280whp,

how much boost will i need to make 280whp @ 8:4:1

You can't have the best of both worlds... STREET = HIGHER COMPRESSION, 1/4 ONLY = LOWER COMPRESSION... 9:1 is as low as I would ever go on a daily driver. Why go lower if you will need to increase the boost just to attain the same power? Your off boost power will be weaker, so it doesn't make logical sense to go lower than 9:1 on a street car. Higher compression and good tuning beats lower compression anyday on the street. You have more USABLE power. bla bla bla

[dug]

dealing with boost + compression, here is a formula I was using to show bauley civic that higher compression lower boost is the way to go...
((boost psi / 14.7) + 1) x motor compression = effective

((10 / 14.7) + 1) x 9.1= 15.2 :1 effective C.R
((10 / 14.7) + 1) x 11.1= 18.5 :1 effective C.R
((15 / 14.7) + 1) x 9.1= 18.2 :1 effective C.R

[graphic]

so lets say i leave my stock compression ratio...10.1

you are saying that i will make more power with less boost

as opposed to 9:1 with same or higher boost..

if i chose to leave it at 10:1

how would i build the bottom up

1. resleeve block

2. forged pistons with a 10:1 compression

3. and rods

who makes forged pistons with a 10:1

do i have to rebuild the head of the block??
now that i am running high compression plus boost???

[kuruptracing]

Imp i would go with 9.1 compression if your gonna plan on drivin it on the street. This way you don't have to boost as much like dug is sayin and then you also will have more power when your not boostin. And you will still be fine runnin 12-15lbs. Also, what kind of engine management are u using?

[graphic]

nothing real big...just the erl mf2 and a adjustable fuel pressure reg..stock injectors and the additional 2 440cc injectors...and a msd btm..oh...don't know if this would be considered engine management but also a spearco intercooler