1 Week to Fit a Dash Into an Unknown Rally Car
What happens when someone reaches out to us to rescue a rally car with a one-week deadline?
Obviously, we deliver. Otherwise we wouldn't be able to look at ourselves in the mirror.
Context
As a driver, rally was never really my thing: I've spent almost all my time on tarmac tracks. But I grew up watching WRC and Sébastien Loeb winning the whole thing year after year, I have a soft spot for Group B, and rally runs deep in our home département, the Yonne. That scene is how I've come to know so many amateur and semi-pro racers.
So, as crazy as it sounds, when someone called with a last-minute connector and an AIM dash to wire in, I was the one asked to save the day.
The car is a Ford Puma equipped with a Sodemo EV11, a semi-pro/pro ECU sold by Sodemo and tailored to racing series rather than amateur drivers. It runs a fully sealed milspec harness and a Sodemo dash, which is currently out of commission and probably beyond repair. Being a pro-level product, it uses our favorite milspec connectors: in this case, a Souriau 8STA61035SN.
The matching connector is a Souriau 8STA01035SN, which in theory ships within 48 hours, but I couldn't source the correct positioner for my AFM8 (oddly enough, I have the one for the 8STA6...). Sodemo, which today is more or less part of Ligier, managed to find a leftover sitting on a shelf with 15cm of spare wire on it, and as the stars would have it, it reached us 12 hours before the driver had to leave for the rally.
Then there was the dash itself, a used unit: according to Sodemo, a newer AIM dash wouldn't have the required protocols. That seemed odd, given that both Race Studio 2 and Race Studio 3 (RS2 and RS3) support the EV11 and EV14 ECUs. The dash we ended up with was an AIM MXL from around 2008, with a hacked-up harness and no PC cable.
The Plan
- Figure out a way to connect the AIM MXL to RS2
- Connect the pre-wired Souriau to the "AIM pre-made harness"
- Configure it for the EV11
- Make a mount for the existing gauge cluster
AIM MXL to RS2
The AIM MXL is a relatively old product, but a well-documented one. You can either use the factory-provided cable (a passive USB-to-3.5mm jack cable: GND, D+ and D- wired straight to the jack contacts, no converter inside) or wire your own connector onto the harness.
That's where we hit our first real problem: while the Souriau side of things was solved, checking the pinout of the provided harness showed that the connectors themselves were damaged. Someone had tried to remove pins without unlocking them first.
AIM never used to publish which connectors or pinout it used, but I happened to know, since I have the same connectors on my Autozam AZ-1, for which I'm currently building a PnP kit. So, for anyone who needs to repair an AIM MXL harness, the parts are TE/AMP Multilock 040:
- Connector 1 housing: TE/AMP 174046-2
- Connector 2 housing: TE/AMP 174045-2
- Pins: TE/AMP 173681-1
After an express order from our friends at rs-online.com, we could finally check whether that used dash actually worked.
Finishing the harness to the Souriau
Once the express delivery from Sodemo arrived, we spliced everything together with TE butt splices and some Tefzel wire, leaving enough spare length just in case.
I also included a face-mounted USB port so that we can dial in the configuration without having to pull the whole dash again.
Configuration in RS2
Configuration was pretty straightforward: pull the existing config to make sure everything works, then push the new one for the Sodemo EV11.
Making a mount for proper PnP of the dash
The owner was ready to grab a drill and make new mounting holes, even though that would have made it impossible to refit the Sodemo dash once repaired.
Given how obscure the Sodemo dash is, with no technical drawings or brochures in existence, we used a pair of calipers and a 3D scanner to replicate the existing cluster and dash setup. That scan became the reference for an adapter that bolts to the cluster using 2 of the 4 original holes, and carries the AIM MXL on its 4 bolt holes.
The end result is fully reversible and fully plug-and-play inside the cluster, and it even brought the dash closer to the driver, which turned out to be an unexpected bonus for readability.
Conclusion
Of course, everything had gone far too smoothly, which could only mean something was about to go wrong. The EV11 doesn't expose everything over the CAN bus, and battery voltage was easy to sort out, since the AIM MXL measures and displays it on its own. Oil pressure, however, was a dead end: we couldn't get into the Sodemo software despite trying four different serial cables.
The stopgap was to fit a mechanical oil pressure gauge until the owner works out which settings to change in the Sodemo software, so that the oil pressure reported over the CAN bus is one the AIM dash can display correctly.
If you have a similar project on a similar timeline, you know Shiba Performance will deliver, so you can make it to the Saturday rally and come home with the class victory and P8 overall.