High/Low Octane Tables Canada Vs. USA?

[cmitchell17]

I might try going to a colder spark plug range, and couldnt I mabey get away with running a lower octane. It seems like you should always be able to run 87 octane with a stock CR with good timing.

When does Knock get dangerous (in the manuel it says dont worry about if you hear pinging crusing up a hill) at WOT high airmass?

The way I see it is that there is a diffrence between detination and pre-ignition. That pre-ignition is when the mixture ignites before spark occurs, and detonation is when spark has occured and the mixture ignites somewhere else and it causes really high pressures in the cyl. for a very small amount of time?

[joecar]

Knock is never good, but it's deadly if sustained under load (high airmass, regardless of rpm).

[SSpdDmon]

http://en.wikipedia.org/wiki/Octane_rating

[dc_justin]

joecar, you seem to be very knowledgeable in tuning.

Does this look like Burst knock to you?

I seem to get alot of spikes like this.

Re: Burst Knock:

That isn't a symptom of Burst Knock. The effect of "Burst Knock" would be seen upon an influx of air, whereas the knock you see is at steady state and low load.
The PCM's effort to stop burst knock from ever happening is a reduction in timing that does not show up as knock retard.

[joecar]

Re: Burst Knock:

That isn't a symptom of Burst Knock. The effect of "Burst Knock" would be seen upon an influx of air, whereas the knock you see is at steady state and low load.
The PCM's effort to stop burst knock from ever happening is a reduction in timing that does not show up as knock retard.

Good point.