SL-C Electrical System

I'm going with and end-to-end MoTec system for engine management, traction control, display, logging, etc. Here is where I'm at:

Qty.Part NumberDescriptionUnit Price
1 M130 MoTeC ECU $2,340.00
1 GPR MoTeC GPR Package (traction control, launch control, etc.) $1,160.00
1   MoTeC Level 2 Logging $375.00
1   MoTeC C127 7” Color Display $2,680.00
1   MoTeC C127 Display Creator (software enable)  
 1   MoTec C127 Enable I/O - 6 AV 2 AT 2 DIG 3 SPD 4 Aux Out $463.00
1   MoTeC C127 Flush Mount Bezel $178.50
2   MoTeC Bosch LSU 4.9 Lambda Sensor  
1   LTC-D, Dual Lambda to CAN  
4   MoTeC DHALL HS230, 3/8"-24  
1   0280 026M, Bosch Fluid Temperature Sensor, 1/8" NPT - Engine/Oil Temp  
1   Race-Spec 150PSIg, 1/8" NPT - Fuel/Oil Pressure  
1   MoTeC 10hz GPS $180.00

Information regarding the pressure sensor used for the master cylinders and clutch are located on the Pedal Box page.

Power Distribution

The kit ships with a nice power distribution system from Infinitybox, but I decided to upgrade to a couple of MoTeC Power Distribution Units (PDUs). Next step is to create a spreadsheet that maps out all of the electrical circuits to the PDUs, ECU and display.


I'm not crazy about the looks of MoTeC's keypads so I've started to look for some alternatives:

Battery Isolator / Kill Switch


Several SL-C builders have used the Braille GU1R, it's small and lightweight. How to connect two batteries described here. The Antigravity ATX-20 looks great:

  • Weight: 4 lbs 11 oz (2.13 Kg)

  • Size: 6.875" x 3.44" x 6.125" (mm: 175x87x156)

  • Cranking Amps: 780

  • Amp Hours (pb Eq): 25

  • Negative Terminal Location: can be ordered on left or right

  • Max Charge Rate: 12 amp


The alternator is a high-end, billet CS-130 style unit from MechMan. They estimate that B8165170M with a 54 mm pulley will generate 120 to 130 amps at idle.





The MoTeC ECU, GPS transceiver and digital display were delivered today. The quality of the case is outstanding not to mention the display itself. MoTeC appears to have their act together with respect to software and product modules. Many of the features in their embedded devices are activated via software keys. I assume the branded USB stick in the foreground does exactly that. It will be quite some time before I know for certain if MoTec is as good as their reputation, but so far I'm impressed.


Dual Half Bridge

Joel recommends either of the two dual half bridges

  MoTeC DHB RaceGrade SSD 2
Price $482 $240
Inputs 2 4
Outputs 2 4
Termination Two DTP and One DTM Connector Not teminated
Size (mm) 31.4 x 38.0 x 14.0  
Supply Voltage 7v - 55v 8v – 40v
Wire Size 12 AWG  
Operating Temp. -50° to 150° C  
Max. Steady State Current 20A Total 10 Amps per output (40 Amps total)
Peak Current 500A (is this actually inrush?) 50 Amps (thermally limited)
Peak Inrush Current 100 Amps (transient pulse must be <100 μsec)  
Operating Frequency 50 KHz @ 28v DC to 1 MHz
Max Case Temp. 125° C  

Rear view camera and monitor

Cutting edge rear view with integrated RADAR and overly graphics HERE


Horn: Wolo (419) Bad Boy Air Horn - 12 Volt ($32.00)

Test Harness

I had Joel at RaceSpec make a test harness for me. I haven't had time to use it yet.

Deutsch Connectors

Most of the connectors will be Deutsch DT Series connectors. The manual, parts diagram and videos below provide pretty much all of the required information to install the connectors. When creating a custom harness and upgrading connectors on devices you can wire the connectors however you want. I'll use the following conventions:

  • The plug connector (i.e., the male part with the female sockets) will be installed on the vehicle’s wiring harness. The reason for this is that if the connector is left disconnected and live, it would be nearly impossible for a foreign object to be lodged inside the connector creating a dead short.

  • The wires on the plug connector are numbered and the following convention will be used:

    • Two-wire connector

      1. Ground

      2. Power

    • Four-wire connector for two devices

      1. Device One Ground

      2. Device One Power

      3. Device Two Power

      4. Device Two Ground

Series Max Current Contact Size Contact Style Contact Plating Wire Range
DTM 7.5 Size 20 Solid Nickle or Gold 22-18
Stamped & Formed Nickle 20-16
DT 13.0 Size 16 Solid Nickle or Gold 20-16
Solid – Green Stripe Nickle or Gold 16-14
Stamped & Formed Nickle 18-14
DTP 25.0 Size 12 Solid Nickle or Gold 14-12
Stamped & Formed Nickle 14-10

Other tools

The Stripmaster wire strippers from Ideal are really nice.

Design Tools

I’ve been playing around with RapidHarness to design the harness.

External Control

Rear View Mirror