Description
Transbrake Lockout Circuits by MGI SpeedWareYour race car deserves a reliable and high-quality transbrake lockout circuit
MGI’s relay transbrake lockout circuits are designed to lock out the transbrake once the transbrake button has been pressed and released.
- Prevent inadvertent use of the transbrake once a car has been launched on a race track.
- Also useful when using an air shifter switch mounted on the steering wheel.
- Proudly designed and assembled in North America.
- Caution! – leave the arming switch in its OFF position when the transbrake is not intended for use.
While competitor transbrake lockouts are mostly timer circuits (where the driver has to be very aware of the timer settings), MGI’s transbrake system is a no-brainer preventative lockout. If the driver makes a mistake on the tree – for example, accidentally releasing the transbrake button too early (say he/she forgot to step on the gas), then the driver simply has to manually flip OFF and ON the arming switch to reset the circuit.
3 vs 4 relay controllersthe right lockout controller depends on your transbrake solenoid

3 Relay Transbrake Lockout Circuit (TRTLC)
- Controller rated 10A
- Dimensions: 5.5″L x 3.75″W x 2.975″D
- Requires a momentary pushbutton or Microswitch that is rated minimally 10A

4 Relay Transbrake Lockout Circuit (FRTLC)
- Controller rated 30A
- Dimensions: 5.625″L x 3.375″W x 2.75″D
- Requires a momentary pushbutton or Microswitch that is rated minimally 1A
- Your choice of built-in fuse: 15A, 20A, 25A, 30A, 35A, or 40A
The selected fuse should be 3x the rating of your transbrake amps. (applies only to the FRTLC)
How To UseSimply arm, engage, and release your transbrake – but only once!
STEP 1 – Arm Your Transbrake
To arm the transbrake, turn on the transbrake arming switch. At this point, the transbrake push button is live.
STEP 2 – Hold and Launch
With the transmission in 1st gear, press and hold the transbrake pushbutton to engage the transbrake. Release the pushbutton to launch.
STEP 3 – Reset the Circuit
Once the pushbutton has been pressed and released one time, the pushbutton will no longer function until the transbrake arming switch has been turned off then back on (causing the circuit to reset).
InstallationHow to wire the transbrake lockout circuit

Kevin Stafford (verified owner) –