F4r pistons in a F7r

[volymmannen]

Hello
is it possible to use F4r pistons to lower cr on a f7r engine. what CR do you get without modify the pistons. ??

[16v_paddy]

Don't take this as gospel from me but......I've been told that you can use F7R low compression pistons in an F4R block, but the compression ratio would be slightly higher than the 8.5:1 it would be in the F7R block

so I'm assuming F4R low comp pistons in an F7R block would give a compression ratio lower than 8.5:1

not got a clue of the exact numbers but I hope that helps

[volymmannen]

So a standard f4r piston will slightly lower the CR on a F7r. i want to lower the Cr to use turbo but i dont want 8,5:1 as i will be using ethanol i want 9-9,5 ... and low boost for starters.dont looking for massive power.
but perhaps it is easier to get low comp pistons instead of f4r..

[16v_paddy]

I'm not sure with standard pistons :? But I think they raise the compression in an F7R block

I know that on the low compression pistons from wossner, the F4R items have a deeper dish than the F7R's giving the differences in compression ratio

[robi1000]

When I was in a market for a new pistons I was looking at F4R pistons and afaik they raise CR a little bit in a F7R block (std pistons).

[volymmannen]

ok.. thanks
better go for lowcomp pistons and 20psi then 8)