86v6CP

I have a 2.8 camaro that I use for autocross racing. Since I am running against V8 cars I would like a bit more power. I'm wondering how much compression the Iron head engine can handle? The class I'm in I can change anything but the throttle body. I was hoping for an 11:1 comp 3.4 liter and about 200 Hp at 6500 RPM but realistically I know I'll never see that due to the restrictive heads but what is the limit for an iron head v6 N/A?

project89

iTrader: (1)

u can run 12.0 or more depend son how u tune it and what u use for fuel

gm used to sell a high compression piston for the 2.8 that i think was a 11.5 or 12.0 cr piston

86v6CP

so if and I do mean if I can find a set of these UBER rare GM pistons and match a cam to them with ported and polished heads, I could see ??hp at say 6500rpm??

Oh and can the 2.8 pistons be used in the 3.1 or did they not change the rod length?

chevyracingrox

the pistons will fit, its the same bore. its just about finding them and possibly getting them to work without blowing something up.

86v6CP

I was thinking OEM 2.8 flat top pistons in a 3.1 for a raised compression on the cheap.

firstfirebird

iTrader: (3)

They will stick too far out of the bore (aprox .300" more than the 3.1 pistons)

86v6CP

OK so the 3.1 used the same rods as the 2.8 and changed the pin height

oh well I'll start looking for the UBER rare GM 11-12:1 comp pistons

86v6CP

If I can't find these pistons what other ways can I raise the compression. I imagine the heads could be shaved but then there's intake issues and it goes on and on.

Project: 85 2.8 bird

you can only shave teh heads so much before you have to start shaving the intake to keep teh angles between them good. run a thinner head gasket, or if you're feeling really balsy, no head gasket, & o-ring the bytch!!!!! (rings on teh block, so if you need to shave the heads again, the groves won't be affected. (experiment on an s-10, jeep, or isuzu engine )

maybe even put the csi on a manual switch

firstfirebird

iTrader: (3)

You have more options if you swap in a 3.4, but using the 2.8 and tuning equipment you can use the 3100 top end on it and have about 11:1 compression and still run pump gas.

project89

iTrader: (1)

isnt there a ford piston that fits the 2.8 to bring up the compression?

Project: 85 2.8 bird

idunno, but the Mustang II v6 was a 2.8......

bl85c

iTrader: (2)

Do I really need to bring up what Ilja_hamburg did again? 2.8 pistons can be made to work with a 3.1 crank by milling the pistons (don't remember how much). Gives you 10.4/1 cr with 0 deck height. But again it depends on what fuel & cam you're using.