Computing Comp ratio

[98spydert]

I'm putting a motor together for my AWD talon. I have a 4G64 block and crank, I'll be using eagle h beam rods for the 2G 7 bolt and a 1G head. I want a 8.5-8.7:1 comp ratio. The Wiseco piston part number K548M865 says it yields a 9-9.3:1 comp ratio which is too high for my tastes. What thickness head gasket would I need to get that down under 9:1?

Wiseco catalog here: http://www.wiseco.com/PDFcatalogs/SC05_mitsu.pdf

 

[CanadianTalon]

I'd run custom pistons for a little bit extra dough instead of jimmying with a thicker HG.

 

[98spydert]

I'd run custom pistons for a little bit extra dough instead of jimmying with a thicker HG.

Any specific reason why that would be a better choice?

 

[tmizer]

Seems like you need to search a bit harder, and certainly not limited to DSMTooners either. In fact, this is the last place I'd search. Would have started at Wiseco or Cometic's website or maybe Googled first.

Method for determining compression ratio is not rocket science, been around since, oh, the "Mustang" ... but since you asked, and I have the same 2.4 block and K548M865 pistons:

my CR spreadsheet for 4G64 w/K548M865 pistons

 

[98spydert]

Seems like you need to search a bit harder, and certainly not limited to DSMTooners either. In fact, this is the last place I'd search. Would have started at Wiseco or Cometic's website or maybe Googled first.

Method for determining compression ratio is not rocket science, been around since, oh, the "Mustang" ... but since you asked, and I have the same 2.4 block and K548M865 pistons:

my CR spreadsheet for 4G64 w/K548M865 pistons

, reason I asked here on toonerz is because I figured someone has already done it and... wow I was right! Thanks for the spread sheet.