11:1 or 12:1

[RIDEREDson]

I know 12:1 compression you have to run race fuel, but does anyone know the power difference between the two? For instance, a 416 with 11:1. Will it noticeably lack power compared to a 416 with 12:1? Is it worth the extra power to spend more money on race fuel?

[Gibson]

I would think there would be a small difference in power, but not enough to matter. 11:1 would be cheaper in the long run because you wouldn't have to buy race gas. Trust me, a 11:1 416 with a Stage two hotcam will give you plenty of power

[RIDEREDson]

I will mainly be doing it for MX. I know its a 416 but it should be fine for local races. Once I get better then I'll upgrade to a 450.

[lilyamaharacer4]

Since when do you NEED to run race gas on 12:1? Mine along with other 400s run 12:1 without any pinging running on just premium, 250fs come from the factory running 13:1 and 13.5:1 and those even are ran on premium. So please tell me why you need race fuel on 12:1?

[matt14c]

Usually it is because of the pinging and temperature for the air cooled motors. Now for that 250f the liquid cooled motors can handle alot more compression before having to go up on octane. I belive its 14.5:1 for the newer high performance fourstrokes before they tell you to consider race fuel. But im not 100%.

[drew416ex]

Originally posted by matt14c
Usually it is because of the pinging and temperature for the air cooled motors. Now for that 250f the liquid cooled motors can handle alot more compression before having to go up on octane. I belive its 14.5:1 for the newer high performance fourstrokes before they tell you to consider race fuel. But im not 100%.

Yep, also they have the timing set so it can handle a lower grade fuel to prevent predetonation.