Spark controller

[Baker72chevy]

What does a spark controller do?

[Minkota]

if you are referring to an Ignition Controller like the "MSD" type, then it has a much stronger spark which is needed in higher compression engines. they also allow for "Rev Limiter" and in some cases a "2-Step".

[rpmerf]

MSD stand for Multiple Spark Discharge. Under like 3000 RPM, it gives 2 sparks. Above 3000 it gives 1 big spark.

Agree with the previous post, they usually have a built in rev limiter, and you can sometimes (depending on the model) set up a staging rev limiter. When you hit a button, there will be a lower rev limiter, so you can launch at the perfect RPM every time.

There are other features, like start up spark retard. This is useful for engines with a lot of initial advance, it makes it easier to start. They can retard timing for things like boost or nitrous.

[Baker72chevy]

This

[rpmerf]

Retards timing in 3rd gear by blocking vacuum to the vacuum advance. There are several threads on it. Search TCS or trans controlled spark. Most people just remove it. It is connected to a solenoid on the pass side of the intake.

[68 P.O.S.]

Originally Posted by rpmerf

Retards timing in 3rd gear by blocking vacuum to the vacuum advance. There are several threads on it. Search TCS or trans controlled spark. Most people just remove it. It is connected to a solenoid on the pass side of the intake.

Close, it stops the vac advance from working until the engine is at operating temp and the trans is in 3rd gear. Yes, people remove it because its an early, archaic attempt at emissions control and it no longer serves any good purpose.