Laemmlej

Excuse my ignorance on the topic in advance

hi all I am assembling a 97 1.8l BP. In this motor there will be Supertech 11.0:1 pistons with weisco rings at a 83.50mm bore. I am seeking advice on what I should run for piston ring gap for the top and 2nd ring. The vehicle will start out a N/A application but will shortly after move to a turbo application running around 5-6psi. The Supertech piston sheet recommends a ring gap of 1mm (.039”) top ring and 1.2mm (.047”) 2nd ring. The seems extremely excessive to me even being turboed and high compression. I was looking at the ring spec sheet for it and was doing the math of bore x .0045” top or .0055” 2nd ring and it was coming out to a .016” top and .018” bottom which I know is to small for this application. I am confused at how much ring gap I should be aiming for and am wondering if anyone has experience with this or advice. I know the turbo guys with the 9.5:1 run around .020-.023” which is what I am leaning towards but am unsure of.

what do y’all think I should do? Follow the Supertech piston sheet? Or stick to what is known to work?

thanks In advance! Attached is the Supertech sheet and weisco ring sheet

Oh4One4

I'd do .022-.024, maybe even a hair bigger. If I were building it for myself, not caring about oil consumption. A hair tighter if that is a street engine and that is a concern. Usage is important.

92dx

iTrader: (2)

Just a heads up, this is the thickness of the rings, not the gap.

What fuel will you be running with 11:1 and boost?

Laemmlej

oh I appreciate that. I just assumed it meant gap thank you. I will be running straight e85.

Laemmlej

ok that’s what I was thinking aswell, appreciate the input. Definitely gives me clairty as I figured that was the general gap I would need