Rev limiter

[SBSerpent]

Trying to understand how the rev limiter kicks in on my 351W (stroked to 392). 'Stock' Ford Racing motor with a Holley Street Avenger 770 carb and MSD ignition. Is it the coil that cuts the voltage or distributor that retards the timing or....? This is on a BDR build #983 with no mods.

[Gaz64]

Depends on what MSD system you have.
Most cut random cylinders from the firing sequence.
Dropping random cylinders allows them to clear up for the next sequence.
Some systems offer a soft and hard cut, some only a single stage hard cut.
Gary

[SBSerpent]

But more so, where are the 'brains' behind the action? Is it at the coil? Does it sense an increase in firing then decides to cut the spark? Is it the large box unit where the tack output is located?

Or maybe its the ECU?

Its an MSD 6 series with a Blaster SS coil.

[Gaz64]

The MSD 6 is the brains or ECU, if you like.
It receives engine rpm input, as a trigger signal, then disables firing events from the firing order according to what rev limiter chip is added.