Octane for a 479 big bore kit

[ejh2011]

i just bought a 2004 yfz yesterday it is bored to a 479...question is is it hard on the motor to mix like maybe 3 gallons of 110 and 2 gallons of 91 octane? 110 just gets expensive but i dont want any harm to the motor at all so i may just run 110 to be safe

[sixer3]

what compression and cams are you running?

[blaster12s]

i got a athena 470 with hotcams and 13to1 and i do about 4gal of 110 and gal of 91. works pretty good but i can deff tell when i run the full race gas.

[sixer3]

I personally wouldn't run more than a 50/50 race/pump mix at 13:1 with a stage 3 cam but better safe than sorry :) you definitely don't need straight 110, excellent topic on compression and octane etc int he powertrain forum

[ejh2011]

it is a 13:1 compression i just been running one gal of 91 and 4 gal of the 110 works good thanks for the help!

[yfzrider690]

Originally posted by ejh2011
it is a 13:1 compression i just been running one gal of 91 and 4 gal of the 110 works good thanks for the help!

You only need to run a 50/50 mix for 13.1. Anymore and it's just a waste of race gas, unless it's not that big of a deal to you.