Im looking at getting some pistons and rods for my daily boosted setup.

What are the benifitis of runnig 81.5mm over 81mm Pistons in my b18c? I will not be sleving the engine so everything has to fit in standard block.

At the moment im only looking at running about 15psi but hopefully one day getting a bigger turbo and upping the boost.

What are your recomendations in the way of pistons and rods?

Thanks, John

 

I would say to get your cylinder bores checked.. If you are at or past the limit you would then need to get the 81.5mm pistons and get the engine bored to work with them..

 

Stock bore is obviously 81mm. Considering the wear and tear of the original pistons on the cylinder walls, you want something the cylinder walls nice and fresh to put in your new pistons.
you have to take material off the walls to get it all nice and clean, so go 81.5mm bore when you rebuild

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by exospeedAMcrx &raquo;</TD></TR><TR><TD CLASS="quote">Stock bore is obviously 81mm. Considering the wear and tear of the original pistons on the cylinder walls, you want something the cylinder walls nice and fresh to put in your new pistons.
you have to take material off the walls to get it all nice and clean, so go 81.5mm bore when you rebuild </TD></TR></TABLE>

 

Thanks guys.

What sort of compression am i looking at going with the 81.5mm?

 

thats on you. depends on how you want the setup to be.
you can choose from compression in the 9:1 to 9.5:1 range.

or you can go with a 10:1 to 10.5:1 range.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wappid &raquo;</TD></TR><TR><TD CLASS="quote">Thanks guys.

What sort of compression am i looking at going with the 81.5mm?</TD></TR></TABLE>

9:8:1 flat top pistons or 9:0:1 to run more boost on pump gas

 

i assume ur boosting...so i would run a lower compresson....
i deffiently agree...bore it out to 81.5 help out those new pistons with a nice surface

 

go .20 over(81.5mm)... you wont be disappointed.

 

I obviously wanna go low compression. But what are the differences between 9:1 and 9.5:1 in terms of tuning, driveability. I will be running on 98 pump gas, so do I have to facor in this? or doesnt it make much difference?

As i said above I would like something that will be good for running about 200-250kw but then have the ability to make more when I get a new turbo.

Thanks again, you guys are helpimg alot

 

I would stay around atleat 9:5:1 for street car. you should be able to make good numbers on pump gas and good spool time. I personally run 9:0:1 in my street car cause I want to run big numbers on pump gas. My car is not daily driver either.

 

damn if you have 98octane..i think you could run 10:1...just keep it under 10psi...that should make a really nice power band as well
the lower the compression the lower the torque will be on the bottom end....higher comp...more torque....but also more of a chance of detnation....

i have shitty 91 octane gas here
i'm runnin 9.5:1comp....i run 15psi it's a true daily driver...and runs great

 

Yeah, def do 81.5mm....TRUST ME (from personal experience)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gt42r_civic &raquo;</TD></TR><TR><TD CLASS="quote">go .20 over(81.5mm)... you wont be disappointed. </TD></TR></TABLE>
you mean .020 over =-0

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lucidvtec &raquo;</TD></TR><TR><TD CLASS="quote">damn if you have 98octane..i think you could run 10:1...just keep it under 10psi...that should make a really nice power band as well
the lower the compression the lower the torque will be on the bottom end....higher comp...more torque....but also more of a chance of detnation....

i have shitty 91 octane gas here
i'm runnin 9.5:1comp....i run 15psi it's a true daily driver...and runs great</TD></TR></TABLE>
we ran 10.2:1 compression 15 psi on 91 octane without sleeving it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mo0cow &raquo;</TD></TR><TR><TD CLASS="quote">
</TD></TR></TABLE>
its probbably 98 RON thats more like 94