I saw HPD has a 11.5 forged piston and am curios if anyone has something similar to that and what kinda of gains are acheivable with it?

 

Compression is power. The main thing is to find the line of where you ride, and what you are willing to do for performance. I presently run the 14.5:1 dome on my 400 and am gonna switch to the 15.5:1 dome. More snort!!! I can buy 110 octane race gas in Mpls for $2.91/gal. so I don't mind. Not sure what the 500 requires for that compression, but maybe keep in mind what's available for fuel around you. You can also use octane boosters....although some frown on them. The Super 104+ which you can get at Walmart (the black bottle) works in a pinch when you're on the trail...kinda fits in the enduro pack. Hope I didn't state anything you didn't already know. I would imagine that's a Wiseco piston. They are really good quality. Before you install it, maybe have the est $40 Swaintech ceramic coating applied. Once again, maybe someone out there could post if it's that beneficial to the 4 strokers. Suck, sqeeze, bang, and blow....the engines of today whether we like it or not.

Good Luck,
Ken Thompson

 

I don't tknow what the Scrambler is stock. 9.2:1? Each compression point is about a 3% HP increase. That is also about the equivalent of dropping down 1000 feet in altitude. You might want to port the head while in there too.
I would love to run race gas t about 12:1 once my motor gets older and I need to go in there. [img]i/expressions/face-icon-small-smile.gif[/img]
Wiseco seems to be the company I hear all the good piston stories about too.