i wonder?

[Guest empracing]

hey guys i was playing around in the shed today and found some interesting parts i forgot about

what is a y34 piston? its out of a L28 i have but the motor was in a none standard form when i got it like the head is from a smaller motor etc

also i cranked up the Lengine calculator to see what head i should use out of my stockpile for a new turbo motor im building and i got this:

stock L28 na

n42 head 8.29:1

p90 head 7.38:1

is this right? because if it is im thinking about running my n42 and less boost because i have a monster turbo set up for a later date and the 90 can go on that what do you guys think?

p.s i dont want a lecture on what heads better im only interested in comp ratio

[Dan Baldwin]

On a dished-piston motor, yes. Flat-piston motor with N42 is 9.8:1, with P90 it's 8.5. For N/A, you definitely want a flat-top piston bottom end.

[Guest Anonymous]

I'm pretty sure that eventually you get to a point of diminishing returns with the whole dropping the compression ratio more and more and raising the boost more and more. I've read in a couple of places that somewhere between 8 - 8.5:1 is the best compression ratio for a turbo motor, so I'd try and stick with somewhere around that. You can fine tune the compression ratio when you get new pistons, which is what you're going to have to do if you want to run a lot of boost.

[Guest empracing]

yeah im not after a lot of psi in this first motor thats why i wondered weather i should just use the n42 for now and save the p90 for when i get serious still dont know what a y34 dishtop is then hey? i cant find it in my books