When swapping a sequential transmission into one of these cars it’s important to find a way to tell the engine to reduce torque while shifting. You can either do this with a strain gauge input and multiple custom maps or using a unit like the geartronics unit along with a single custom map. Given the simplicity we’ll cover using the Geartronics Unit here.
Geartronics Unit
Start by wiring your geartronics units “Cut Signal” into the CPC solenoid circuit. This enables a method by which the ecu can see the input and react to it.
With that installed you can set up your custom maps.
Custom Map Parameter | Setting | Function |
|---|---|---|
Activation | Always Active | |
Enable | In all drive modes | |
Output | Ignition Base Timing | Add Map Output To Channel |
X Input | CPC Pressure Sensor V | Interpolate Between Cells |
Y Input | Engine RPM | Interpolate Between Cells |
Setting it up in this manner allows you to have a reduction of timing (in the example 30 degrees) whenever the geartronics units receives the cut signal from pulling the shift lever. The unit also sets up a delay for how long it occurs, otherwise you can add a custom map to control the delay and how long it holds the cut for.
Shift lever strain gauge output (integrated in the drenth gearbox kit) to ECU’s CPS voltage input.
CPC solenoid output to Clutch switch input via external circuit below:
This circuit generates fake clutch switch signal (off=12V, on=0V) even driver doesn’t actually depress clutch when pushing shift lever (downshifting).
Then making custom map as below:
Map 1: recognize CPS voltage as shift force.
Map2: Integral map which starts counting down the calc only value (initial 1000 down to 0) to count elapsed time since when driver starts operating lever.
Map3: Cuts total fuel volume according to Map2 value (for upshift shift cut).
Map4: Retards ignition timing and decays according to Map2 value (for upshift shift cut).
Map5: Generates fake clutch signal according to Map2 value (generates signal when driver downshifting)
Then upshift cut is made by above custom maps and downshift blip (significantly shorter blip than regular blip) is made by RR autoblip feature.
This way enables upshift and downshift without driver depressing clutch at all.
Maybe RR Flatshift feature for upshift cut, but I didn’t use it because I wanted to set fuel cut and ignition retard time separately.