oversized pistons...... just wanted to know if it would increase at all?
and also...any advantage to using oversized over standard size?


and also if you could explain how?






Thanks

 

Hi,

I believe displacement is bore x stroke. Bigger pistons have a bigger bore, so you are increasing displacement slightly. Generally, more displacement will shift the TQ curve up. Of course, you're not adding that much displacment with oversize pistons. Maybe you'd be a 2.04 liter? I'm sure someone can chime in with actual specs.

The other thing to consider is your cylinder walls. Sometimes you need oversize pistons since the walls are worn and need more than a hone. When I had by Integra GSR built up, I had stock bore pistson put in, but if I were to do it again, I would probably go oversize hoping it would help with oil consumption and whatnot.

Thougths or corrections?

FB

 

yeah what ur saying makes alot of sense.
but wouldnt a downside be that the cylinder walls may be thin now

 

pi*R^2 * stroke = cc (volume) .. by right you gain more cc per mm of bore than stroke

 

Yeah that's a good point. I think it was more of a concern in an open deck design like my old Honda. The 4g63 is pretty stout, right?

Other input?

FB

 

Depending on what your doing with the car, I'd only go one factory step up or so in bore size, leaving room to overbore again in the event of a mishap. There are other benefits to opening up the bore in the block. Most importantly it allows you to "de-shroud the valves" to a greater degree. The Indy boys run a very short stroke with a nice size bore for this among other reasons. Of course to take the most advantage of a larger cylinder bore on your block, you need to have the combustion chamber opened up to match in the head. There is a wealth of information on this subject all over the web.

 

you'd gain some compression as well as displacement but very minute.

 

cool..guess I'll have to get some head work done