Hey im thinking about the 686 (102mm) set up i want a mild set up!! BUT my question to you guys is the bore??? are the + 2mm pistons prone to blowing up the piston?? I heard a couple rumors and im wandering whats true?

Also so i dont have to add another post---> should i do cams with a 102mm piston bore? and the last question do i have to run race fuel? or a higher octane fuel?

 

if you dont' want to run race fuel I would get a true 11:1 102mm ROSS piston
and I would Deffinately go with the stage 2 hot cam........

 

oh really? that seems cool but i just red an old post that said that i should deff. run race fuel from 100 to 105 in it!! i dont know if i should or not? also BigScary i was thinking about the 11:2 102mm piston from JE do you think i would need race fuel in that? and arn't the web cams better?

 

I have to give this a little bump ----> Does anybody know?

 

ANYONE???????

 

What are you asking?


Your need to run race fuel will be determined on what piston you decide to use. If you use the 11/1 JE piston, that most people have, you will need to run race fuel. BigScary was saying you don't have to run race fuel if you use the 11/1 piston that is actually 11/1 compression ratio.

Assuming you meant 11:1 not 11:2, you will probably need race fuel, unless the casting for the piston has changed. Talk to your builder to know for sure.

I prefer the Hot Cam based on price and wear&tear in the motor. Webb might have one cam that offers more power than the stage 2, but not without some more work than what your talking about.

 

Welll to tell you the truth i have no clue what the 11:1 or :2 or compression ratios are!!! i think i know but deff. not cause i have no clue what your talkiing about can you clarify me on that?

 

The JE pistons are advertised at 11:1 but they are 12:1 if you don't remove material from the combustion chamber during port&polish. There are other 102mm pistons available that will keep you at or below 11:1 so you can run premium pump gas. If you go higher than 11:1 actual compression ratio and don't run high octane race fuel, it looks like some pistons (JE) and stock rods won't take the punishment. I know Craycraft sells a true 11:1 compression ratio Ross piston, don't know how other builders do it. I second Scary's recommendation for a Stage 2 Hotcam, that would be a good running combo.

 

Thankyou so much SO you are basically saying that i should go with the 11:1 Ratio true ross piston from craycraft and the stage II hotcam would be a good setup right? okay so lets say i buy that and install it what # fuel would you reccomend?

 

well, i would suggest for you to get the race gas in buddy, because with the je pistion in your raptor engine you will definitly feel the change with the race gas. Because if you want speed and for your raptor to react that the best way to go. with regular octane gas and that je piston your quad will suck.