Here's the deal I've got an H22A4 block with scratches on the no. 3 cylinder wall. I believe there from a broken piston landing. I burn oil when I get on it. Anyways I'm going to rebuild the bottom end. I'm going to resleeve the block, probaly Darton flanged sleeves. What I want to know is how much can I bump up the compression with 94 octane. I want forged pistons, so where can I get them if I want to overbore the block say 87mm to 88mm? Who's got a formula for calculating compression? How much HP will I get going from 10.1:1 to say 12.1:1?
Any and all suggestions would be appreciated!

 

i ddint know darton made these as well... have you checked into the closed deck conversion set up they have?


[Modified by GudeH23a, 6:15 PM 11/2/2002]

 

Yeah I talked to them about the flanged sleeves, they said that you could run up to 10 pds of boost with them. I didn't talk to them about a closed deck setup. What does the setup consist of, and what kind of gains would be made from it?

 

Can anyone answer my questions?

 

With proper tuning, you could run very high compression on 94 octane. Personally I am running 11.5 on 94 mine is tuned, and a couple friends were running nearly 12:1 on 94 octane, stock fuel.

My 11.5 pistons were made by Arias. The rule of thumb is usually 1 CR point = 10hp.

 

Does anybody know who sells overbore pistons. I know you can get forged pistons, but I've only seen standard bore.

 

Anybody?

 

im 12.5 to 1 45lbs of fp, no det built head and runs on the street daily. Arias +Saenz have fun

 

JE makes 20 over pistons for the H series motor, if you want larger then you'll have to have them custom made.

 

JE has off the shelf 90mm pistons, but they are 9:1 turbo pistons.

 

Anybody no where to get a formula for calculating CR? Say I want to go with 88mm pistons with 40 thousands milled off the head. Also does anyone know how much Bill Gude mills off the head of a 5th Gen Lude. I've emailed him, but he never replies? 1320in1 How did you get to 12.5:1? I've only seen the JE forged pistons that were 11.5:1. Did you also mill the head, or a thinner head gasket?


[Modified by Yuleluder, 5:47 AM 11/5/2002]

 

You could try the tech forum, cause I have no clue how to calcualte it, cause it's usually done by doming the piston which is done by the piston maker.

But the way you are describing you would find the volume of the cylinder you removed by milling the head and subtract it from the capacity at full compression....then recalculate compression


[Modified by satan_srv, 12:54 AM 11/5/2002]