Fuel

[Dr.D]

I use high octane now since the new Lush HC pistons but it did run fine on regular gas in the stock configuration.

 

[Claviger]

Everyone should keep in mind dynamic compression vs static.

The stock engine is a low static (8.7) high dynamic (8.4) configuration, which is why it makes so fing much torque down low.

Built ones tend to even that relationship out so the static is more appropriate for the dynamic and doesn't bias it to low RPM so much, which is why so many built bikes can get away with 87. An 11.4:1 static 265 kit has a 9.3 dynamic.

 

[Tripps]

What's the difference between static and dynamic compression?

 

[Claviger]

Hmm, worth a Google. It's better explained by smarter people than I, essentially it's the working compression ratio that accounts for cam timing.

 

[phar2slo]

And here I am thinking again about putting 100 octane in my beast. Would be a waste.

Did full up on the weekend with 98 but knew the trip home would be a high speed event limit here is 100kmh / 63mph spent alot of the time at 140kph and higher at times.

 

[Jvheli]

What's the difference between static and dynamic compression?

My understanding is static compression is basically derived from bdc to tdc. Dynamic is after the intake valve closes to tdc. I may be fuzzy on this tho.....

Regarding detonation. It will, I heard it, my tuner heard it. But only did so while we were (he) was trying to find the best power tuning wise. Something to consider for you fellas that experiment. I feel the variable is load. Not simply rpm timing and throttle position. That said, this motor seems like it’s pretty well designed to avoid it.

Not agreeing or disagreeing with any others. I use premium cause it makes me feel better protected. I beat on my bike prettying hard, and I can afford a few extra dollars and lose maybe 2 or 3 hp running premium.

 

[atlsrt44]

I've only run higher octane in boosted engines

 

[Claviger]

My understanding is static compression is basically derived from bdc to tdc. Dynamic is after the intake valve closes to tdc. I may be fuzzy on this tho.....

Regarding detonation. It will, I heard it, my tuner heard it. But only did so while we were (he) was trying to find the best power tuning wise. Something to consider for you fellas that experiment. I feel the variable is load. Not simply rpm timing and throttle position. That said, this motor seems like it’s pretty well designed to avoid it.

Not agreeing or disagreeing with any others. I use premium cause it makes me feel better protected. I beat on my bike prettying hard, and I can afford a few extra dollars and lose maybe 2 or 3 hp running premium.

It definitely can be induced if you try .

I will admit I did go to 9 range plugs, and COP to limit it. 7 and 8 range plugs were showing banding on the insulator indicating they were overheating. COP simply to ensure timing accuracy.

 

[Tripps]

Why are coil over plugs more accurate timing? Sorry if I ask too many questions, but I was even worse as a kid, trust me, lol

 

[Idaho Red Rocket 3]

All I know is my 2006 3 pipe Standards owners manual said to use 89 octane. I always used the Premium. Here it is only 91 octane. After I read the Owners Manual and saw the 89 recommendation I tried it. After about a month of using 89 it started running crappy. Went back to 91 and no problems ever.