[Mk2] [Turbo] which forged pistons/compression ratio.

[nicholasmitchellmr2]

Hi guys,
Im rebuilding the engine in my rev2 turbo at the moment, this is the spec at the moment:
ct26 with 360degree bearing
3 inch decat and 3 inch system
st205 chargecooler system
forge actuator
fcd
mbc
balanced bottom end etc etc

i need new pistons as one of mine was cracked, i am looking to get forged pistons, the block has been cleaned and honed, i measured it today and its 86.08mm on average on all 4 cylinders.
The head was only skimmed 2/1000th's of an inch or so, so i will be using a standard head gasket.

the question is do i go for pistons which raise my compression ratio to 9:1 or do i use 8.5:1 pistons, and also which pistons have you used? there are plenty on the market just wanted to know everyones views/opinions.

thanks for any help/advice, cheers!!!!

[nicholasmitchellmr2]

anyone??

[^Trickster^]

go for 8.5:1 it will be a little higher with you having the head skimmed, not sure if you had the blocked decked or not, but either way youll be close enough to stock and it will be fine.

Graeme

[Grajey]

If it's a daily driver I 'd go for CP pistons. Actually, I did go for CP pistons!

Less thermal expansion than some others and therefore no piston rattle when cold.
With the turbo you're using there is no need to consider CR other than slightly improved throttle response off-boost with a higher CR.
As I said I used CP pistons giving 9:1 CR on my REV3 with stock REV3 HG. I have an overboost issue, controller set-up for 1.6 bar, and have seen 2 bar boost and it's still all holding together

HTH

[JJ]

I've tried all of them.. and find the CP pistons being the better quality along with the JE's.... Though I find the JE expand and contract at a larger rate and make things a little more noisy ( neglegible though )

Matter of preference though with regards to C.R. I'd go for the higher compression ones as this will improve responce off boost / cruising .. also on boost, run lower boost for good responce too !