No, pre-iginition is caused by the metal surfaces in the ignition chamber being so hot they ignite the fuel/air mix without a spark. They both screw your engine in about the same way by burning fuel before it is intended to ignite.
You might want to get that story in writing in case you have a warranty issue down the road.
-DanD
...he COULD fit an aquamist (or similar) water injection setup and then fill with 87 octane all day...
[/devil's advocate]ken
ah, why don't people top off with evian after a tankful of 87? OK, H2O and gas don't mix, but it's not really that simple.
florian
Thanks for clearing that up, I have a hard time distinguishing between the two. Is there a more general way to distinguish between them? I think I've read that running with too much ignition retard can also cause pre-ignition by heating the exhaust valves too much. The exhaust valves are hit with the flame front and cannot dissipate the excess heat in time for the compression cycle.
In article ,
Pinging or detonation refers to simultaneous, or closely following, ignition from a residual heat source in the chamber AFTER the ignition spark. The shock wave generated by the collision of the burning wave fronts creates the "ping" and does the damage. Some degree of detonation can be tolerated without damage, tho it can damage pistons etc.
Preignition refers to ignition prior to the ignition spark, while the piston is still being driven down the cylinder in the compression cycle. Earlier preignition is more destructive than later, closer-to-the-ignition spark, preignition, as the piston is being mechanically forced down the cylinder for a longer portion of the compression stroke, while the burning fuel- air charge is trying to expand. It is considered
*much* more destructive than pinging, with the occurrence of even a single incidence of detonation being enough to destroy the engine.Steve
I'll also add part of the reason is because the explosion from the ignition spark increases the pressure in the entire chamber - even in parts where the flame hasn't reached.
From what I understand, it takes some serious neglect for there to be preignition. There would have to be some awfully heavy carbon deposits before it would reach that point.
You guys should have read a thread in the Toyota group a few years back. I mixed up preignition and detonation, and there was an ensuing argument over whether or not "predetonation" was a correct term. One guy was telling me no way, and it devolved into a discussion about English syntax. My point was that some mechanics and even a well known tuner used the slightly bastardized word "predetonation".
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