LS7 Porsche gearbox calculated GEARS display

Discussion and support for MoTeC's previous generation ECUs.

LS7 Porsche gearbox calculated GEARS display

Postby mldc on Wed Sep 08, 2021 5:56 pm

Hello, community,

I have a customer with LS7 engine and Porsche gearbox.
I've installed Hall Effect sensor with 6 equal space trigger wheel on the left drive shaft.
Shown speed is correct in each gear and we are happy with that.
Speed is shown on "Left driven wheel"

But I'm struggling with the Gear display.
Can someone check the ECU file and help me to configure gear display?

Gear, diff ratios is already into ecu file.
Trigger wheel (6 tooth) and sensor is on driven wheel drive shaft. Speed is shown correctly.


Looking forward
LS7 Gears.e35
(72 KiB) Downloaded 82 times
Posts: 1
Joined: Tue Nov 17, 2020 8:39 pm

Re: LS7 Porsche gearbox calculated GEARS display

Postby NathanB on Thu Sep 09, 2021 9:28 am


As you are using a drive speed to calculate the gear ratio, you have a few settings wrong.

The gear detection is trying to calculate the tailshaft speed - in effect the gearbox output speed.

It knows the input speed (minus clutch slip) based on the engine speed.

As your tailshaft speed is going to be calculated to remove the final drive ratio from your drive speed, tailshaft speed source needs to be set to 0, and not 1.

From there you will need to work out your tailshaft speed cal, which will be a negative number, as you are using a drive speed. to calculate it, the help has a worked example for you.
Tailshaft speed help.PNG
Tailshaft speed help.PNG (32.68 KiB) Viewed 856 times
Tailshaft speed.PNG
Tailshaft speed.PNG (41.81 KiB) Viewed 856 times
Posts: 41
Joined: Thu Oct 15, 2020 12:50 pm

Return to M400, M600, M800 and M880 ECUs

Who is online

Users browsing this forum: Google [Bot], Majestic-12 [Bot] and 4 guests