VR wheelspeed sharing?

[C. Ludwig]

Doing an S6GP install. Car is equipped with VR wheelspeed sensors. These sensors are connected to a standalone ABS controller through the OE wiring. Would like to share those sensors with the S6 on the AN01-04 inputs. What is the proper way to wire them and not degrade the signal to either the ABS unit or Syvecs ECU? Thanks!

[pavlo]

That might be tricky as the S6 biases the inputs via a pullup resistor and is not a true differential sensor. The effect it will have on the signal will depend on the input impedance of the OEM ABS controller and the internal resistance of the sensor. Without having already tested it, all you can really do is try it and see what happens, I would initially try a sensor and use a 0-5v input as although the sensor will be bi-polar, it may already get pulled up by the ABS controller.

Depending on the vehicle there may be an option to use a can bridge to input the wheelspeeds into the S6 from the OEM CAN system. If neither a 0-5v input or bipolar input works on the S6 you will need to look at 4 channel buffer to output signals to the S6 without affecting the sensor inputs to the ABS unit.

[stevieturbo]

Would something like this work ? It might stand less chance of confusing the base signal for the ABS

http://www.jbperf.com/dual_VR/v2_1.html

Then it would change the signal to digital ?

[pavlo]

That would do it perfectly, and for $6 shipped it's a steal!

[TimH]

$6 shipping, not shipped lol. But still a good find and a good price

[pavlo]

It did seem rather cheap!

But to solve that specific problem it should do it nicely.

[stevieturbo]

On that same note...

Quoted from a user over on the DTA forum....with a find of the same nature.

, I discovered something I think is quite a cool and easy solution recently that saves having to mount hall effect sensors on your hubs if you already have VR style ABS pickups out there.

The Mk4 Vauxhall Astra (and I am sure Corsa's etc) WITHOUT ABS was fitted with a nice little signal converter that kind of turns the VR sensor into a Hall effect one to output a signal and drive the speedo unit (the abs cars send a signal from the abs unit). This type of car, plenty in the scrappers;

It takes every full wave from the VR and turns it into a square pulse, which the DTA seems to read without issue. To be honest I am not certain on it's exact voltage output, as I am new to oscilloscopes, but it seems to be around 4 volts top to bottom, with 1 volt as its base voltage when there is no wheel speed, so 5 volts overall at its peak.

(On a side note, I at first thought it would output 12 volts due to me feeding it with 12 volts, and had planned to try feeding it 5 volts. )

Anyway, they can be found in the Astra under the steering column in the fuse box, and are the tall orange relay looking unit top left;



Part number can be seen here;



As for wiring it up, what I found worked was;



Pin

15 - 12 volts
31 - Ground (I also put my shield wire for the VR cable to this)
Out - Yep, output to ECU

IN1 & 2 - VR sensor connections. These seemed to work perfectly either way around for me, but I am yet to test at high speed. If it does fail at speed I plan first to try switching these around.


- Mark

[pavlo]

Thanks for the info Steve, that is great.

[stevieturbo]

Weird...I just quoted his text and links. Not sure why the image cropped

Full part number is, apparently thats a Siemens number

09.185.826
PA6.6-GF25

Good point, the Vauxhall No. is 9134755 I think.

There are other similar little circuits I found online to do the same job. Those are maybe the neatest.

[Ryan.g]

Those Siemens adaptors are what i use on the Supras, work a treat

Although 99% of ABS computers will work fine if you T into the + side of the ABS signal at ABS Ecu and then set the input to only 5v on the input selection in sensor setup with the Bipolar inputs on the S6GP. (no pull-up is applied then)

Ryan