Can anyone enlighten me as to how the Type-R and GSR bottom ends are different? I know they have a different compression ratio but why? Are the pistons different or is it in the block/head? Are the other specs the same? Rod length, stroke, bore...

More or less, I'm trying to figure out if putting Type-R pistons in my GSR would be worth the effort. Or is there another reason for the compression difference.

 

The pistons comp are different and the type r crank is balanced and a tiny bit lighter in type r that about the only differences in the block. Now the heads are different.
And to answer your question. No is not worth the effort to put type r pistons in a gsr if the gsr is running fine. I would do cams/valve train intake manifold a good header on a gsr before even tearing apart the bottom end.

 

Well I've got the Skunk2 pro intake mani, a port and polished head with port matching on the intake and exhaust side and a multi-angle valve job. And I've already got a new valvetrain assembly on my list of needed things.

What I'm trying to figure out is will ITR pistons alone raise my compression or would I need the whole bottom rotating assembly?

 

dont waste money on porting and polishing.and getting rid of the stock intakemanifold is a good start on a Gsr..if your going to put ITR pistons in your gsr upgrade the cams also to Itr cams to work with the higher compression

 

Well I'm planning on a set of aftermarket cams that are slightly more agressive then the stock GSR profile. Do you know what the lift and duration are on the ITR cams?

 

http://www.phearable.net/tech/cams.txt

 

That is an excellent link. Definitely saving that to the favorites.

 

according to those numbers the buddyclub 3's arent much better then oem Type R's. Interesting..

 

Yeah. Looking at a lot of them, the lift isn't much larger but the duration... DANG!

 

Same bore, stroke... Rods are lighter and stronger, pistons are higher compression and molydeblum coated. Pistons are what change the compression ratio over the GSR. I have a write up on another site I did about all the differences, I could list them all if you wish lol