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91 versus 93 octane

Thanks for the info Tank. Problem for me is the stations here only have 87 or 93 and I was concerned that maybe the steady diet of 93 might be causing it to run hot.
 
The Tank said:
Running a steady diet of 93 should be no problem, IMO. Premium here and further west and north of Arizona is generally always 91 and it is hard to find a station with 93. It seems that East of here premium is 93.

BTW, my 1995 EVO runs great on 87 octane. For those that think your EVO needs high octane, it doesn't. The owners manual for my EVO says it needs 87 or higher octane fuel and that is what I use.
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As strange as it sounds, I believe that running a higher octane gasoline is actually a bit cooler (assuming the same qty of gasoline vaporized). The amount of physical energy released is more, the amount of heat energy less . . . AFAIK . .that is!

Mark - Thanks!:newsmile026:
 
Longer, slower and cooler . . . but it contains the same amount of energy - weird huh?
Here's an interesting site: Does higher octane gas burn hotter or cooler then lower octane gas? | ChaCha
and Does 93 octane gas burn hotter than lower octane gas? [Archive] - Classic Cougar Forums - cool stuff - literally!
Although slightly off topic, diesel engines create more mechanical energy from the same amount of fuel than does gasoline - therefore it runs 'cooler' . . . How can diesels run cooler than gas? - TDIClub Forums gasoline releases more 'heat' energy . . . I always wondered why diesel engines have smaller radiators for the same output . . . or so it seems . . .
Mark - Thanks!
 
Interesting. Thanks. I'm just trying to figure out why my 07 EGU would now be showing signs of a lean tune after all these years. Just doesn't make sense. Don't want to through money at it if not necessary.
 
hogcowboy said:
Interesting. Thanks. I'm just trying to figure out why my 07 EGU would now be showing signs of a lean tune after all these years. Just doesn't make sense. Don't want to through money at it if not necessary.
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Ethanol may cause some of this or you could be developing a vacuum leak in the intake.
 
Gasoline.

..High Octane = slower burning under pressure
Lower Octane = Faster burning under pressure

Low octane fuel has More BTU's than the High Octane.

signed....BUBBIE

added: Most motors will run a little Cooler using the Higher Octane. Slower burning/more octane = less heat (less BTU's)
 
If you can find some alcohol free 89 octane try it, my bike runs good on it with NO knock:s
 
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