Had a recent newbie with question on whether a non chrono MINI could be made into a chrono MINI. There were responses that the topic had been addressed in the past and it was just about hopeless.

It got me thinking on how a MINI speedo works, is there a cable per the days of old, or is the speedo all electronic? Anybody know how the center speedo sends a signal to the non chrono tach so that there is a digital speed read out? If the signal is electronic perhaps there is a way to tap into the signal and have it operate an aftermarket type speedo.

 

Delete, saw the other thread...

 

Some mix up of different issues here. Our Mini's relies on wheel speed sensors to determine road speed. These are 1 on each wheel that also used by ABS, ACS, and DSC, and flat tire monitor. It is a free ride for the ECU for getting MPH information. From what I infer, the speedometer is driven by the ECU which control it like a stepper motor. This is how most if not all modern cars implement analog-like gauges.

The challenges of converting a non Chrono pack car to Chrono or vise versa has to do with how MINI check if the modules belong to the original car, to that I have little first hand knowledge.

 

I am going to dig deeper into this. I am thinking the key is how the speed is sent to the LED readout on the tach. If there is fluctuating voltage then might be able to get a gauge with a needle that swings from left to right upon increased speed/voltage. Would get a dial made up to reflect the actual speed. Could have the speed on one side and either boost or oil temp on the other.

For me with a vert it would be very nice on a sunny day.

 

I have been wrong countless times before. I am quite sure based on logic there is no analog voltage anywhere you can tap into in our Mini's to get a road speed signal. The LED readout on the tech is driven digitally by a microcontroller which decides on which dots to illuminate. If I have not mistaken, it is a dot-matrix kind of display. Our Mini's are mainly digital beasts.

 

Had to ask, foiled by BIOS beeps again.

 

There is a VSS (Vehicle Speed Sensor) wire in the wiring harness under the passenger side door sill.
http://www.fes-auto.com/upload/doc/1...er%20Guide.pdf (page 12)

 

Will have to find out what type of signal is it pushing.

 

It is the typical VSS found in some cars: https://www.google.com/search?q=vss+speed+pulse+signal
BTW, it's worthwhile to check if that wire is available in the wiring harness inside the right side access panel. This harness runs down the right side in the the door sill and it depends on where the VSS wire enters the bundle.

 

Interesting the direction this thread took. I have briefly gave thought to an up/down shift indicator. I normally do fine on the track without one. There had been a couple of times that I was distracted doing point-by for faster cars to pass that I lost track of my upshift. Thankfully the redline cutout came and saved the day.

Evidently (Matt Richter's) Proshift is no longer in production, and it claims to be the only true gear-dependent shift points reminder product in the market. It takes the RPM information from the ODB connector, and a VSS signal running along the passenger sill. This VSS signal, I suspect is likely one of the 4 raw wheel speed sensor signal - which I expect to be pulses with frequency proportional to the road speed. Most vehicles employs a tone ring and either a magnetic or hall-effect sensor.

I can use a shift indicator on the track to lighten the brain processing load.

 

For what's worth, Matt's Proshift piqued my interest on this "VSS" signal. I did a quick and dirty lookup on the Mini schematic. Matt's is too smart to mess with the raw wheel speed sensor, for safety and liability reasons!

The yellow with green stripe wire connects between the ABS control unit and Navigation Control Unit and Outside Mirror Folding Control Unit. Both of these are options. Hence I infer it is an output from the ABS unit to non-critical functions that is safe to mess with. Cool!

 

Got to research to determine whether the MINI VSS signal is Hall effect or AC sinewave.