Msd

[older racer]

hi, I see how MSD wires their relay 8961 into two step and clutch switch.
how does it switch from high side to low side?? the instructions in book doesn't tell you anything . I tried calling all three numbers, and no answer. do you have to install a switch , to select high side and low side ? just curious, as going to install the relay in a clutch car. like to know before hand. thanks

[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.

[Jim Caughlin]

Jim, I understand your point about wiring the line lock and low RPM two step together being a problem for burnouts but if the RPM is too low for clutch lockup wouldn't the simplest solution be to just add another inline switch to override the two step during burnouts only? Just switch it back on after the burnout?

[FED 387]

Why not use a 3 step. Burnout/launch /top end MSD # 8737 about $100 I have a new one sell it for $60 plus mail. Fed387