water injection questions

[Michael Fawke]

[snip]
>Octane is derived mainly from experiments done on a special engine (motor
>octane) along with a chemical method (research octane).  The two are
>averaged to get "pump octane". 
[snip]

No - both tests are done on the same test engine, but with different inlet
charge temperature and engine speed (I think that's all). The Motor octane
number is supposed to be a much better approximation of 'real' operating
conditions.
Michael Fawke
Canberra, Australia.
fawkacs at ozemail.com.au