building h23 vtec and i will be running on pump gas 91 octane. its going to be my DD.
what pistons should i use Type S or the h22a4 if i want to tune on hondata p72?

 

ok...h23 or h22 rods?

 

h23 rods and i will be using skunk2 pro series stage 1 cams

 

type S pistons will put you mid 11's in compression, however you will need to have the SE of the rod rebushed for floating wrist pins.

if you use the JDM pistons (10.6) you will be right at 11. With this piston you just have to have the wrist pin pressed in. No actual machine work is needed.

just be sure to have the bottom end balanced (crank, rods, pistons...etc)

 

koo thanx man i will be running the h22a4 pistons

 

I'm building an USDM H22A4 with a brand new block. I want to run higher compression than the stock 10:1, but I can't find any pistons for my application that are compatible with the FRM. I believe the JDM Si R-spec runs 10.6 or 11:1. I know that there are some differences between the two engines - like no EGR valve and OBD1 ECU on the JDM, but is the block any different? Does the R-spec have iron sleeves? I need to get pistons ASAP so that I can get this car back together, and I'd love to run the higher compression if possible, so it would be awesome if someone responded to this posting soon. Thanks!

 

There are more in-depth threads on here on the topic, but there are a few manufacturers that make FRM-compatible pistons. The one's I can think of right now are Mahle and Jun; you can also use the Type S pistons to get 11:1.

98vtec - Are only the Type S' floating? I thought the H22a4's were floating as well...

 

h22a4 and type S.

 

Awesome! I've called so many local shops and JDM gigs, and nobody could give me an answer. Now I'm excited and probably won't get much sleep. I should have joined this site a lot earlier. Thanks a lot guys!

 

Where's a good place to find pistons for the Type S? What about the rods...can I use my current ones? Also, I've already got 4 sets of new OEM rings, think they'll work?