Looking for a light forged setup and came across the evo 9 oem forged pistons.
From what I've read they fit and drop good.
But the difference in the combustion chamber affects the compression.
It drops from 8.8:1 to somewhat 8.0:1.
Has anybody used this setup??
And does a compression this low really affect performance enough to say don't get it?

True, but I'm not looking at making HUGE numbers nor want to keep it at stock levels.
This is why, these are perfect.

you would be better off with 2g pistons as alot of people have been pulling the wrist pins out of the evo 9 pistons in our configuration due to having to rotate the piston 180 degrees. normally around 400-450 hp.

What does rotating pistons mean?

inorder to run the evo9 pistons they must be rotated on the rod 180* due to a 1mm offset.

Evo pistons in their stock configuration are 8.8:1, in a dsm 7bolt motor with a head that's been milled before your compression goes somewhere in the 8.5:1 neighborhood (same as 2g pistons). Evo pistons are forged, and have a friction coating on the skirts like aftermarket forged pistons (why i would prefer them over 2g pistons IF and only if price wasn't outrageous). I have not heard of anyone having any trouble with evo pistons on 2g 7bolt rods (same as stock evo rods) other than having to rotate the piston 180* to have the pin offset correct. With that being said i would say stay away form the pistons dsmgraveyard sells and their rings.

here is a guy that has been running the evo 8 pistons for a while and he explains it a bit more in detail.

http://www.dsmtuners.com/forums/newbie- ... lp-me.html

what it comes down to is that if you instal the pistons with the dot facing the timing belt as supposed to then the valve reliefs and wrist pin offset is off. meaning the larger intake reliefs are on the exhaust valves.

Damn i guess ill look elsewhere.

The reliefs on the pistons being backward didn't have any effect on my motor (stock size valves). So I wouldn't worry to much about it.

But I thought u said to stay away from these pistons?

Lol he meant to stay away from the evo pistons and rings that dsmgraveyard sells for some reason people have had badluck with the stuff they sell.

You install them with the dot facing the timing side, the wrist pin offset will be correct just the valve reliefs are back wards but it does not matter there is enough clearance because these pistons sit lower than ours. The problem is that the rings are expensive 150 from dsmgraveyard if you can get them and $200 from for OEM, there aren't any other options.

Like wally said, i meant stay awar from the ones they sell.

Whats wrong with your current engine?