Pistons?

[ItzGenX]

What are the differences in the grades of pistons? In this catalog I got each type comes with 3 grades to choose from. 1,2, or 3? Which is best?

[Stoneage_Turbo]

got me on that one ...hope someone has a awnser

suppose its the strenth of the piston? like a 1 would be astock replacemnt 2 would be high compression and 3 would be low comperession for turbo?,or maybe its the ammount of boost heat or compression they will stand up to ? without seeing the catalog i wouldnt know where to start , whatca trying to do ?i hear alot of det guys have the block bored out to accept 300zxtt pistons

[ItzGenX]

Don't want to bore a DET out because the sleeves are thin as it is. If you are going to bore it out you need new sleeve inserts etc. The pistons are all of the same compression, I think the grade is the heat index or strength of them. So does anyone know any manufacturers that make upgrade pistons for the SR20? (not turbo low compression ones) Maybe some 9:1 or 9.5:1 pistons.

[KRPSICHI3]

Tomei, Greddy, HKS....too name a few My friend has and SR20 bored to a 2.2 litre and it runs great.

[KRPSICHI3]

Sorry I should have said SR20DET.

[ItzGenX]

I am not going to bore mine. It is dangerous for the power levels I will be running. Tomei, Greddy, and HKS make only low compression turbo pistons. (8.5:1)

[eric96ser]

The grades of pistons are just like the grades of bearings. They refer to the size of the bore in the block. I think a stock SR20 is 86mm, but the pistons come in sizes that are measured to the .01 of an inch. Almost every SR20 I've seen has grade 2 pistons. Look at the back of the block, that number is the piston grade. There is no way to tell what size pistons you need without taking the head off.