I have a GS-R motor with 12.5 compression JE pistons, I want to know what would be the best route to go with lowering the compression to around 11.1-11.5. If I use two head gaskets where would my compression be? Or am I better off swapping pistons?

 

Swap pistons

http://www.c-speedracing.com/h...c.php

 

so whats so unstreetable about ur current setup?

seems to me high compression means lots of $ spent on tuning, and poor gas mileage.

but why wouldn't you be able to drive it on the street?

A big cam would be more troublesome in my mind, lopey idle and all
or a featherweight flywheel, making it alil harder to work ur clutch.

 

12.5 is the perfect compression for pumpgas for an all motor car.

If you use a larger cam, you bleed off a lot of the compression, which allows you to have a little more tuning flexability.

What cams are you using right now?

 

don't swap pistons, just use a thicker hg, like cometic

 

I got the motor from a freind who owed me some money. HE had toda b specs in them with the valve springs and retainers. He took the B specs out and sold them. I thought a compression of 12.5 would be too high on pump gas and the idle was lopey, but made good power. I plan on taking my ls/vtec out of my eg and throughing in the GSR instead. So should I just keep the 12.5 compression and get another set of toda B specs?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EF8KiLLaBeE &raquo;</TD></TR><TR><TD CLASS="quote">So should I just keep the 12.5 compression and get another set of toda B specs?</TD></TR></TABLE>

Yes, or something different.

Look into the Skunk2 Pro-2, those would be ideal for that motor setup.

 

im going to be running 13.5:1cr on the street with toda spec c's, its all in the tuning dude, obviously with my cr i cant use it to the full potention on pump gas, but im getting 2 chips burned, 1 for pump one for race gas, so i can just put in some fuel and swap chips and go!

 

I was worried about running an 11.3 cr, but my friend has a b18c-1 with a 12.5 cr and does okay. He has his motor tuned pretty well, however, as mentioned before, race gas key to realizing the full potential of that setup.

 

Go with whatever the tuner in your area is comfortable tuning.

Talk to him to get a better idea and he can reassure you for anything thing you need to know about your compression. That's because that's what it all comes down too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HondaIntegraR &raquo;</TD></TR><TR><TD CLASS="quote">don't swap pistons, just use a thicker hg, like cometic</TD></TR></TABLE>

why the hell would you want less quench area by doing that?

what cams are you running?

what ecu program are you running?

 

A recognizezble shop I have around here is kingmotorsports( sole distributor of mugen for the us) Once I get everything together I'll have them tune it.