[Diy_efi] Knock sensing - water injection

[Geoff Harrison]

Hi all.
IIRC, knocking = pre-ignition = detonation, which occurs if the c/r is too 
high for the fuel being used. Will also occur if the ign is advanced to far. 
We used to fix the problem with lead. Can't and shouldn't do that. Modern 
practise is to retard ign.
Why not have an injector which adds a bit of something to the mix. Could be 
anything that will slow the burn rate or reduce internal temp or combination 
of both, like methanol or avgas. Even water.

I used to have an acquaintance that used water injection on a small V8. Once 
on the highway would turn it on. Had to shut it down 5 mins before shutting 
down engine. Apparently water has a greater expansion rate than air for a 
given heat rise, making the engine more fuel efficient. Recent searches on 
water injection only come up with spray units for intercoolers. Any one have 
thoughts or experience along these lines.

Regards,
Geoff

Geoff Harrison IT Services.
Port Macquarie  NSW.
Tel 65827181
Mob 0401324639 
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