[kayno100]

i want to change my stock piston to a aftermarket piston what piston is good for power uses normal gas and can change the piston straight away ( no need to change anything else in the engine)?

 

[carpenter]

102mm 11.1 compression 11.5.1 max CP or tech piston

 

[kayno100]

thanks

 

[Banshee2Raptor]

102mm 11.1 compression 11.5.1 max CP or tech piston

Wiseco is a good choice to. I have a Wiseco 102mm (686cc) 11:1 molly coated piston. So far so good with the piston, To bad my sleeve sunk & is getting re done along with new ring's, but the piston is all good

 

[jonny_b]

i got the tech 11.5:1 cp piston because of its true compression, and the larger valve cuts. this way if i choose to go +2 valves with a big cam down the road, it will work. the je pistons, i have heard, are pretty close when doing those things, but idk from personal experience. and aslong as your cylinder coating is ok you can toss it right in. i used one of those auto body scotch brite pads to it just to help with crosshatching, which wasn't really bad to begin with.

 

[high octane junkie]

i run 92 pump with a 12:1 Kenz piston, with no issues at 1000 - 2000 foot altitude. Kenz built +2 motor.

 

[jonny_b]

a 12:1 piston will only work with a big cam. with a stock head and cam, you will need a race gas mix. it may work for one person and not for another. so i wouldn't risk going that high. 11.5:1 is the max safe compression for 91-93 octane.

 

[high octane junkie]

a 12:1 piston will only work with a big cam. with a stock head and cam, you will need a race gas mix. it may work for one person and not for another. so i wouldn't risk going that high. 11.5:1 is the max safe compression for 91-93 octane.

and that's why i stated it was a Kenz built +2 motor.

to the OP: what is being stated with these last two posts is that cam profiles and elevation also affect fuel octane requirements as well. with the proper cam at high enough elevation, a 12.5:1 piston can be ran on 92 pump. now that you're confused i'm sure, the best advice is to call a reputable builder and request reliable advice for your specific application.

 

[jonny_b]

to the OP: what is being stated with these last two posts is that cam profiles and elevation also affect fuel octane requirements as well. with the proper cam at high enough elevation, a 12.5:1 piston can be ran on 92 pump. now that you're confused i'm sure, the best advice is to call a reputable builder and request reliable advice for your specific application.

:thumbsup: good explanation and final advice.

 

[high octane junkie]

good explanation and final advice.

thank you for pointing out the error i made, i should've been more clear in my first post.

 

[jonny_b]

no prob. :thumbsup:

to op, i saw yesterday of a person who has to run a pump/race mix with the 11.5:1 also. so that will depend on how good the gas is in your area. i guess some stations that say 93 aren't really 93 octane. and octane booster doesn't work.

 

[geoman]

i run 92 pump with a 12:1 Kenz piston, with no issues at 1000 - 2000 foot altitude. Kenz built +2 motor.

Me and a buddy of mine ran a racers edge 12:1 with a +1 head and X2 for over a year on 91 with no problems. We are 900 - 1200 ft