Msd

[Bob Gullett]

https://www.msdperformance.com/produ...ols/parts/8739

[Lew Silverman]

The red wire from the two step, connected to and energized by the 8961 Relay controls the high/low function when used with a clutch switch.

http://www.jegs.com/InstallationInst...1/121-8961.pdf
(See Figure #6)

Hope this helps!

[Mike Pearson]

The high side on the 2 step is always active. The low side is activated when power is applied via a switch.

[older racer]

hi, ok, if the line lock sets the low rpm, how do you do a burnout? won't have enough rpm to spin tires, prob slip clutch? I do my burnouts on high side, then switch to low side for launch now. I want to use their relay and rewire my system.

[Bob Mulry]

I think that if you want to control leave, burn out and high side rpm you would need a 3 step......or a switch to turn off 12 volts to the 2 step module with the line lock energized for your burn out

If you put in a switch there will be no RPM limiter for the burn out...

Bob

PS: Remember to turn the switch back on after burn out!!!!!!!!!!!


Are you running an automatic or stick???????????????????????????//

[Lew Silverman]

I may have missed something here, but aren't you using the line-lock/low-side limiter for your burn-out's?

If you need a burn-out, launch AND over-rev protection, you'll need to follow Bob's advice and get a 3-step switch to work with your MSD and relay (although unless you'll be controlling a high-amperage circuit, you may not need one).

MSD has all of their wiring schematics, cross referenced by unit number, on their website, as well as a very handy smartphone app, to help if you need it.

[Paul Merolla]

I just use my right foot to control burnout RPM...seems a whole lot simpler and less stressful on the engine.
Then the switch on the clutch pedal runs the low side limiter.