Spark latency correction

[Ward]

"Spark latency" is a compensation for the delay from the time the spark
delay timer is loaded with the spark advance value untill spark actualy
ocours. This includes inductive delay in the ignition coil. 

Please remember that spark advance is actuall dely, since yiu cant time
travel backwards to start spark, its actualy delay from the prior TDC event.
to calulate a V8 time between TDC's do 15/RPM, 

Example:
15/3000 rpm = 0.005 seconds, (5000 usec)
S0 5000/360 = 13.8 usec/degree.

If you work this out for different RPM values, and plot the usec.deg value,
you will get an interesting curve. 

This may be a problem with low cost timing lights, most of which are not
accurated byond idle RPM, the pro models do comensate for RPM and lamp
delay.

Bet that was more thna you wanted to know?
Ward


On Sat, 18 Sep 1999 18:50:37 -0400, flying.chimp at juno.com wrote:

> Guys,
> 
> The following is taken from the ecmguys dissassembly of Anht. Can someone
> explain this "Spark latency correction"?
> 
> ;----------------------------------------
> ; Spark latency correction, (USEC)
> ;
> ; TBL = VAL/15.26
> ;----------------------------------------
> ;                                           Usec     RPM
> ;----------------------------
> L8129:    FCB 8 ;             122          800
>                 FCB 11 ;           168        1200
>                 FCB 12 ;           147        1600
>                 FCB 13 ;           183        2000
>                 FCB 17 ;           259        2400
>                 FCB 15 ;           229        2800
>                 FCB 13 ;           198        3200
>                 FCB 13 ;           198        3600
>                 FCB 13 ;           198        4000
>                 FCB 14 ;           214        4400
>                 FCB 14 ;           214        4800
>                 FCB 14 ;           214        5200
>                 FCB 14 ;           214        5600
>                 FCB 14 ;           214        6000
> ;-----------------------------------------
> 
> Cheers,
> Wayne Johnson
> ___________________________________________________________________
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