I had posted this question on the "under the bonnet" section, but the people who would consider fettling with detonation detection devices would be reading and posting in the "mods" section. I was able to change from 93 octane fuel to 89 octane without any pinging. If it's because the knock sensor is retarding the timing, then I am getting less performance with 89. If the engine is not pinging because it really doesn't need the higher octane, then I could get a more aggressive timing curve for more performance. Give me the "For real tip". -Jeffy.

 

Yes it does have a knock sensor..., it's under the intake manifold..

BTW, what is the recommended fuel octane for an MC?? Why change to a lower octane?

///Gilbert

 

The tip is this...The car's manual says to not run on anything lower then 91 octane unless its not available. With lower octane you will see lower performance. Reason being is higher octane fuel combusts @ a higher compression ratio. So if you put in lower octane fuel the engines computer has to notice this and retard performance to prevent premature ignition.

This is how I understand it.
I'm not going to post to search on the gas topic (even though there is like 100 of them )

 

Lower octane gas is bought in much greater quantity than 92 octane, especially at today's price. If few people are paying the extra for the good stuff, then it will stay in the underground tank longer- where it's quality and vapor pressure will be reduced over time. As far as the knock sensor goes, I wanted to know if that was the method of detonation protection this engine uses. Of course the knock sensor is what allows me to use the 89 octane without dangerous ping (detonation). Changing to a 180 degree thermostat has given me better accelleration than I had, despite using 89 octane! My mod test results are from a marked distance painted on the road- I know if a mod works by an improvement in terminal velocity at the end of the paint. Have you noticed your MC is quicker before it reaches operating temp? I did, and am now able to enjoy that fuel/ignition curve full-time. -Jeffy.

 

octane rating does not matter because you are not saving anything when your car is running Rich due to your mighty thermostat....

 

my fuel economy. Got anything usefull, or are you just interested in TRYING to knock others? -Jeffy.