water injection questions???

[ptimmerm at mashtun.JPL.NASA.GOV]

>If all a person wants to do is lower the heat of combustion and hence the
>speed of the flame front, then why not just fatten up the fuel curve at the
>point where detonation is expected?  Why add all the extra hardware and
>expense (and risk) of a water injection system?

Water does do more than just cool it.  I think the original post said
that cooling was the major effect.  I would not argue that point.
I will again add that steam is an anti-detonant, and that you can run
much higher boost levels without detonation with water or water methanol
than with fuel enrichment.  There is a big difference.  I seem to 
remember numbers like 10% higher cylinder pressures without detonation
with 50/50 water methanol.  The other point to be repeated is that most
of us don't have unlimited fuel delivery capability.  And since you
dont need to enrichen the mixture with water present, you can run
stronger without leaning out.  This is a big deal with OEM turbo
fuel injected apps.  Stepping down from soap box.  Personally I
don't run it so that will blow up if I run dry, and there is still
a big effect.  But I also run intercooler sprayers at the same time.
they both have very nice effects (measured).

paul timmerman