Compression, timing, and race fuel

[Tommygunn]

Trying to figure out if I'm doing the right thing here. I have 66mm pistons, 19cc domes, cool head, drag ported cylinders, etc. etc. My compression checks out to be 195lbs in each cylinder. My timing has been set to +5 degrees but I'm told to move it to between +7 and +10 degrees.  I'm running straight 100 race fuel because it's easy to get, I can buy it right at the pump 2 miles from home. Is this enough? Or should I be running 110?  Elevation is 500ft

 

 

 

 

 

Thanks

[91coupemike]

I would think you would be on the edge with that much timing.

 

But I don't know squat!

[Tommygunn]

So I guess I should either leave it at +5  be looking for some 110?

[nastyracing]

4 degree of timing max on that. your and the bitter edge of the fuel. if you wanna add that much timing switch to 110 oct min. in my opinion with that much compression advancing the timing that far is actually gonna fight the top end.

[sheerider11]

I've heard mixed ways of doing things. I'd talk to your builder.

I call my builder before any drastic change like that. He knows more then I do what my motor does and doesn't like.

[Nightmare]

 

I'd run the 110.

[trickedcarbine]

4 degree of timing max on that. your and the bitter edge of the fuel. if you wanna add that much timing switch to 110 oct min. in my opinion with that much compression advancing the timing that far is actually gonna fight the top end.

Yahtzee^

[sheerider1026]

Yahtzee^

X3^^

[Tommygunn]

Thanks. I believe I will leave it at 5 degrees and run 110 to be safe