fuel

[adam oconnell]

im running an industrial plus 3.5 briggs ,with tilly 314 carb, was running 100 octane fuel ,switched to vp110 witch is 107 I beleive and lost some power . im wondering why ?

 

[team25]

Not enuff comression

 

[adam oconnell]

it has an angle cut .024 off the head and i installed non dished valves . i dont think ill be able to get much more compression. what do you think ?

 

[Chuck_Sloggett]

Hi octane gasoline does not equate to more power. Fact is low octane 85-87 has more energy than the higher octane fuel and as long as the octane you use does not produce detonation (pinging) it is plenty high enough. In a flathead engine your compression ratio will be very low, probably in the 7:1 +- so you are going to make more power with very low octane gasoline. -- Chuck

 

[team25]

there ya go

 

[jeff4587]

true story!!

 

[keithcar72]

Higher octane fuel has less power per gallon than lower octane fuel. The only reason to run more octane is to prevent detonation.

 

[jack burroughs]

It has the ability to resist detonation and reduce power. Plus a higher cost.