Pistons

[trx400exrider14]

Whats the highest compression piston i can have without using over 93 pump?

[flyboy1294]

Originally posted by trx400exrider14
Whats the highest compression piston i can have without using over 93 pump?

Piston compression ratings alone do not determine what octane you can run without having pre-donation.

The piston compression rating is called static compression ratio. What ultimately determines what octane you need is called dynamic compression ratio. The cam, head gasket thickness, deck height, and some other small factors all contribute to this.

For instance, I am running 12.5:1 compression and have a Stage 3 Hotcam, and I can run 93 octane if it's fresh and not have to deal with pre-detonation. But if I were running a Stock cam or even a Stage 2, it would knock like heck.

Generally though, with an average build, 11:1 is highest you can run on 93, assuming you are going to use some type of aftermarket cam with it.

[dxcody]

^^^^

smart guy right there, and i think if you are going to get a high comp piston, it is well worth buying the $150 hotcam to go with it, so you are really unleashing all that the top end has to offer, i mean why not if you already have it all taken apart

[trx400exrider14]

just tell me if this will work with pump gas, 11:1, stage 2 hotcam?

[ridehonda400ex]

Should work great!

[trx400exrider14]

thanks guys,im gonna try and get everything after the next race,so i have time to get it put on

[ridehonda400ex]

Cool! Post some pics too

[trx400exrider14]

Ill try my best

[426kidz]

thats what im running...i use 93 and it scream!!!!!!!!!!!:macho