Re: [DML] Re: Failed emmissions AGAIN

[mike.griese@xxxxxxxxxxxxxxxx]

Detonation in this context occurs when the fuel/air mixture ignites at the wrong 
time - usually as the mixture is being compressed in the cylinder but before
the spark plug fires.  You hear this as a knock or ping.  This is very hard on 
pistons, rings, and the stuff below the piston as the momentum of the engine
is being checked by the premature detonation.  

This happens more often on high compression engines and engines with
turbochargers or superchargers.  Higher octane gasoline is harder to 
ignite even with a spark, so that is why it is recommended for high 
compression or forced induction engines.  

--
Mike


-------------- Original message from "tuxr" <tuxdarby@xxxxxxx>: -------------- 


> Thanks very much for the info on this, I've been using 93 for this 
> car and my previous, will switch to 87 tomorrow. Since I put 650 
> miles a week going back and forth to work, this is a real cost 
> savings. The forum is great for stuff like this to those of us that 
> aren't very mechanically inclined. But I had what might be a stupid 
> question: What do you mean by "less chance for detonation"??? 
> 

[Non-text portions of this message have been removed]





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