Ocatane and power

[Christopher E. Hill]

> This sounds suspect. My street car (10.4:1 compression) detonates
> just a touch at WOT on 93 octane. If what you are saying is true, I
> would loose torque (and therefore power) if I ran AVGAS.
> 
> I don't believe this for a second, what's your source for this
> information?. Who's R&D?

I have been following this discussion a bit, and one thing that has been
left out is heating value.  If the 93 octane has a higher heating value
(BTU/lb, or kJ/kg) than the AVGAS, then the 93 octane will make more power.
 If you were EXTREMELY detonation prone, then the AVGAS may be better, if
the torque could be restored by getting max cylinder pressure in the
correct range.  You want the most heating value fuel with out detonation
possible for best power and torque.

Also, higher octane does not mean slower burn rate.  It just seems to
happen, but don't allways assume it to be true.



Christopher E. Hill--chill6 at utk.edu