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How to determine knock/ping/detonation
Posted 11 January 2005 - 01:41 AM
My motor seems to be running relatively fine, according to my ears, but I don't know what I should be listening for.
Posted 11 January 2005 - 01:54 AM
Posted 11 January 2005 - 02:09 AM
Posted 11 January 2005 - 02:37 AM
Posted 11 January 2005 - 03:34 AM
I posted a video of it at the XT6.net site:
but have since taken it down. It sounded just like small firecrackers going off as I was approaching 85-90mph. Air/fuel ratios was getting leaner and leaner still since the intake is routed out through the passenger side foglight.
I guess you'd have to hear it at least once to know what it really sounds like. I am not looking forward to hearing it....EVER.
Here's another video from the thread I posted above. A guy responded and said you could hear pinging in his XT turbo.
Posted 11 January 2005 - 10:45 AM
And a couple of definitions: Detonation is when the flame front in the cylinder is supersonic. Pre-ignition is when the burn starts in two or more places (one is normally the spark plug) and the flame fronts collide. Both conditions move the cylinder pressure peak before TDC instead of just after, this creates extreme force on the piston (and everything else).
Posted 12 January 2005 - 12:14 AM
Pre-ignition is when the burn starts in two or more places (one is normally the spark plug) and the flame fronts collide. Both conditions move the cylinder pressure peak before TDC instead of just after, this creates extreme force on the piston (and everything else).
With pre ignition, its not just the higher pressure that does damage. Most damage is caused by the resulting shockwave from the two flame fronts colliding. Hence the noise and the impact loading on the head and pistons.
Posted 12 January 2005 - 01:58 PM
only at, or close to full throttle, and mostly under load
Posted 12 January 2005 - 06:05 PM
Posted 12 January 2005 - 06:54 PM
Posted 12 January 2005 - 08:52 PM
Posted 12 January 2005 - 10:53 PM
An aluminium block, and especially aluminium head does reduce the tendency for knocking to occur, as it transfers heat much faster than CI.
Posted 12 January 2005 - 11:32 PM
I have found that my car almost never does this now that I have converted to SPFI. Maybe it is associated with the older-style disty that is used on the carb cars?
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