running 07 mcx apex at 12pound boost on 91 pump. I have been told that I could turn it up to 15lb for the elevation I ride. Just looking at the numbers for different kits for the sidewinder. Evolution Powersports has a 14lb 238 hp kit with 91 oct. MCXpress has a 15lb 250hp 94oct kit. looking at this. The write up says at just over 200 kpa total pressure(=15 psi turbo pressure "AT SEA LEVEL")for a lambda 0,80. I ride 8000 to10500ft. Would this give me some wiggle room on octane? Also Evo has a 16lb 258hp kit with 95oct. How much boost can I run up here with 91 octane? I want the most horse power without race gas and no problems.
Depends on your kit, I'd install a a/f gauge to be sure that your fueling for the higher boost, my own apex, a 06 came with a probable gen 1 mcx kit, I'm told the 310hp one. meaning a ok turbo brain box, and the smaller 16t turbo. However mine has a aftermarket fuel pump and I removed the one in the tank. Now I've run 18# boost on it all day on 94 octane, no issues. I run 15# all the time. I run, at approx 6k elevation. 18# is more heat than power due to smaller turbo.
Guys I ride with run 15# on 91 pump, hell 1 guy was 89 octane lol... A bit ballsy I think. I run 94 above 91 for extra protection from detonation otherwise kit is fully intended for 91. So your fine at 15#. The mcx kits came with the head shims. The apex is a higher hp producing engine over the nytro for boost and also considered stronger, probably due to the extra cylinder.