Pistons size for Rb20det(78.5 or 79mm)?

[eoskolkov]

Hello and here's my first post,

So I got a piston with a hole on rb20det, i've been looking online for a forged set and found some from supertech. I got two options 78.5 and 79mm. I haven't measured the old ones yet(Don't know everything about the skyline yet since I got the car 2 months ago).

I believe oem pistons are 78.5mm. What would boring to 79mm do. How many CC's would it add? Should I just stay with the 78.5mm. I know some people bore to 82mm and get a 2.2L out of it, but why would someone bore extra .5mm. What gain will that have?

Thanks

[amnash]

standard size for oem pistons for rb20det is 77.925mm ~ 77.975mm

Engine FSM page EN-224

edit: thats actually standard size for the piston skirt. it shows a diagram and looks like it would have the same outside diameter all the way up to the rings.

[Skym]

There's 0.5mm, 1.0mm over size pistons (I think same with factory pistons, rings to suit). Only needed if some of the bores are damaged. Even then you can fit thin sleeves to damaged cylinders.

ACL, Supertech, CP, Ross make forged pistons for RB20DET.

I think it's already 1998cc and is rounded up to 2000cc (2 litre). With forged pistons, around 2.1 litre.

If have a bigger intercooler, turbo, the extra capacity helps with reducing lag at lower rpm, mid, high rpm (more so at lower rpm).