Knocking?

RCZ · 03-17-2009, 11:12 AM

Are you cereal?

Do you mean when you turn it off??

Knocking is premature ignition in your cylinders...it sounds as if there were glass marbles bouncing around inside your engine. What you are experiencing is not knocking...

Knocking with lower octane fuel happens because lower octanage = more prone to combustion. That means that if your motor is running "hot" (lean) there's a greater chance that the air/fuel mixture will ignite before the spark fires (from heat in the cyl). Pre-ignition aka detonation aka knocking is when that happens.

If you are talking about the crackling sounds after you turn the car off...thats just metals contracting as they cool...

03-17-2009, 11:12 AM	#1 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	Are you cereal? Do you mean when you turn it off?? Knocking is premature ignition in your cylinders...it sounds as if there were glass marbles bouncing around inside your engine. What you are experiencing is not knocking... Knocking with lower octane fuel happens because lower octanage = more prone to combustion. That means that if your motor is running "hot" (lean) there's a greater chance that the air/fuel mixture will ignite before the spark fires (from heat in the cyl). Pre-ignition aka detonation aka knocking is when that happens. If you are talking about the crackling sounds after you turn the car off...thats just metals contracting as they cool...