What pistons is everyone using to attain low CR with 54cc stock heads? I was looking at JE online, and the biggest dish I saw was -31cc on a 5.7 rod, yielding 9.0:1 with 58cc CC (I imagine that equates to around 9.6:1 for 54cc CC). I was hoping to get down to around 9.0:1.

Joe

 

Joe: the JE piston you refer to has as large a dish as I am aware of. Another option is a flat top that is further "down in the hole". You loose "quench" when doing this. The importance of quench under boosted conditions is debatable, but obviously you won't be under boost most of the time (assuming it's a street or street/strip car).

Rich Krause

 

Ypu could also open up the stock combustion chambers by 4-6cc or so.

Rich Krause

 

ttt

 

Rich,

Do you think there will be any issues running a piston with so large a dish?

So given all this info most blown stroker motors must be fairly high CR, unless large chamber AFR heads are used....

Joe

 

No, it's not a problem. The piston has a "D" cup design (like I wish my wife had!). There is still a flat quench area. (:1 is [retty reasonable, especially if you are running a big. My own preference is for a bit lower CR, but you should be ok if you don't go wild on the boost, or if you are running abig cam. The only thing wrong with these psitons is the weight, but a blower combo shouldn't have to rev sky high anyway and you need a strong piston.

Rich Krause

 

I was planning on running a small cam, the cam you can see in my sig, and not plan on revving over 6000. I was hoping for 15 psi but will run as much as I can with whatever cr I end up with. I was planning on going with a D1 kit.

Joe