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Race gas and engine tunes

Dirtracer 619

Well-Known Member
So my motor is 10-1 compression and tuned for premium gas

I came across some race fuel 108 oct V P. Can i run that without re tuning
I have hear people run 50/50 race and premium gas. Thats what i was thinking of doing

Any thoughts

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Well-Known Member
You would not gain anything, the peeps who generally run 50 50 have boost, not N/A motors and your compression does not warrant such octane.

Sean At CBM

Active Member
I wouldn't switch over. The tunes are different from race to pump gas. The gas burns at a different rate and will change the air fuel ratio in a bad way. If your tune is good, straight 91 is all you need.

Dirtracer 619

Well-Known Member
Yea thats kind what i was thinking too.
Don't want to wreck a good motor!

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Non Sugar Coated
Higher octane fuels burn slower than say unleaded pump gas if your cylinder pressure is low IE: long duration cam, low compression pistons, etc. The cheaper the better if high up the octane. High octane fuel in a engine with low pressures makes for a real dog your better off with pump gas, if you start adding cooling issues into the equation theirs not enough room here you scratch the surface.