ORIGINAL: kn0bbyba11
ok cool so i have read that the .18 engine usually runs best with the 20% nitro and .21 and up run best with the 30% is that true?
30% will run in .18ci and .21ci engines just fine. All you need to do is retune the engine and maybe also change the plug and/or add/remove a head shim. I personally use 30% for all my engines, .12ci to as large as .30ci.