I'm using 98 grade octane for my 07 Bob, would that help in decreasing engine heat or make it worse?? I got V&H slip ons & everything else is stock.

 

I think it'd make things worse; the higher the octane the hotter it has to be to ignite...

 

Here in the States, we don't have 98 octane available. Our premium fuel is between 92 and 94. I would guess that 98 would have a slower burn rate, whichwould create lower combustion temperatures.

 

Higher octane = lower temps

Drexor has his facts backwards.

 

http://auto.howstuffworks.com/question90.htm

So, basically, a 96 cubic inches motor,giving 65 horses don't need that high octaned fuel, a vrod, with 1200cc and 115 horses needs it.


cheers!

 

warper,

Should I interpret that to mean I should not be using 92/93 octane fuel in my '07 Wide Glide and that it should in theory run better on regular instead of premium?

 

Not exactly, you should interpret that with the kind of engine we have on the dynas/electras/softails/etc... we don't have the imperial need of using a fuel that avoids self explosion at high pressure, because our engines don't have that high presure. However, if you want to use it, use it, in the case of Spain, 98 oct. premium fuels also have additive for better lubrication, which are an addon, and in any case, AFAIK, 95 octane in Spain means maximum 95 and 98 means minimum 98.

In any case, in europe we have 95 (which is 93-95 per lab test) and 98, so I cannot tell how the engine runs on 92-93.

I can tell you that from the ol' days of fuel with 90oct and pb my dad's car run terribly bad with 90oct/pb and good with 95/no pb. And no noise with 98/no pb.

 

Yep ! Read yer manual. Run Premium octaine gas. 91 -93 octaine. If you want to lower the heat. you got to change yer pipes etc. Tmax will help.
Realize yer sitton on top of a air cooled engine also.

 

actually the temp thing has to do with the fact that higher octane has higher energy, as the engine is running at small compression most of the energy is lost in the form of heat. Changing pipes for ones giving better performance will allow more of the energy generated on the explosion to be turned into movement rather than into heat.

 

Also git the resnators out of the newer bikes that try to reburn gasses.