Is Advanced timing BTDC or ATDC?
The opposite of BTDC is ATDC or after top dead center. This describes an ignition event that is initiated after the piston reaches TDC and is already traveling downward in the cylinder bore. In engine parlance, when the ignition event is begun BTDC the timing is advanced and when it happens ATDC it is retarded.
What does 10 degrees BTDC mean?
degrees before top dead centre
On a stock NA model MX-5 the “timing point” is set at 10 degrees before top dead centre (BTDC) when at idle and there is no load. 3. Top dead centre refers to the position of the piston. The piston is at its highest point when at TDC.
What is aTDC and BTDC?
aTDC: after top dead center; bTDC: before top dead center; aBDC: after bottom dead center; bBDC: before bottom dead center. Source publication.
What should ignition advance be at idle?
Most engines have between 5-20 degrees of ignition advance at idle. This is referred to as initial timing. What’s the difference between mechanical and centrifugal advance? As an engine revs up, we need to allow even more of a head start for the spark plug in order for complete combustion to occur.
How does ignition timing affect idle?
Yes. In the case of both valve timing and distributer timing (in older cars with a spark distributer) changing the timing will affect the idle speed at the same throttle setting, because it will affect the efficiency of the engine at that throttle setting.
What is aTDC and bTDC?
What does bTDC mean timing?
Definition: A common term used to indicate the amount of ignition advance. Examples: Setting the ignition timing, so that the spark is initiated before top-dead-center, is necessary because of the time delay before the explosion reaches maximum force.
What is BTDC timing?
“Timing advance” refers to the number of degrees before top dead center (BTDC) that the sparkplug will fire to ignite the air-fuel mixture in the combustion chamber before the end of the compression stroke.
What should spark ADV be at idle?
In Forscan “Spark advance” is about 3 – 6 degrees and “Ignition timing” is a lot more, about 33-35 degrees. These values are at idle.