MoTeC Global Forum

I have a simple feature request for the Bosch ABS Module.

I often use a driver switch to change wheel circumference for traction control (for rains, etc). It would be nice if I could change the Bosch Circumference parameter to a channel so it could be updated by the same function.

Hi Ben,

is that really neccessary? Some years ago, I installed a Bosch Motorsports ABS to some 911Cup Racecars, and as far as I remember, the wheel circumstance was only needed to determine vehicle Speed.
And wouldn't it be easier to have a divisor/multiplier applied to the Speed Signal?
With the 911Cup Racecars the Bosch ABS was connected to the wheel speed sensors, and then all four wheel speeds where send via CAN by the ABS. So with the signal on CAN it would be easy to divide/multiply values activated by a Switch.

Cheers, Mike

it is needed, just look at the latest GT3R, the ATE ABS have that function, but not the bosch unit. so it will be a problem for changing to rain tire(to send the correct wheel speed back to ECU to get the TC done right). in that case, it was done by the cosworth dash and have a lookup table to get the tire size correct.

If you have a developer package or a dash you can do some translating through I guess it's not technically "needed" but it would be one more thing that's technically accurate and much more straight forward. Realistically it's a 5 minute fix at the longest so while it might not be worth it's own update there's no reason not to fix in in upcoming releases.

Hi,

I have added this to the feature requests to be investigated.

Based on the systems I have worked with, the Teves and Bosch motorsports systems handle wheel speeds pretty differently.

The Bosch system self adjusts wheel speeds relative to each other (like it or not).

Is the goal to match true vehicle speed or to address a change in stagger front to rear? Or?

have fun,

Eric Schieb

The Bosch ABS measures rotational speed of the wheel, not the surface speed of the tyre. It internally converts the rotational speed into surface speed with a circumference figure programmed into it, and then it reports this surface speed on CAN.
We read this wheel surface speed on CAN, but what we need to know is the rotational speed so we can then set our own wheel circumference figure and you can correct the wheel speed in the M1 to your wheels if they change size.
The Wheel Circumference figure in the Bosch ABS module is only there to translate the wheel speed reported by the bosch unit into a rotational speed and you should only ever need to change this if you change the wheel circumference in the bosch unit itself.

Darren.

DarrenR wrote:The Bosch ABS measures rotational speed of the wheel, not the surface speed of the tyre. It internally converts the rotational speed into surface speed with a circumference figure programmed into it, and then it reports this surface speed on CAN.
We read this wheel surface speed on CAN, but what we need to know is the rotational speed so we can then set our own wheel circumference figure and you can correct the wheel speed in the M1 to your wheels if they change size.
The Wheel Circumference figure in the Bosch ABS module is only there to translate the wheel speed reported by the bosch unit into a rotational speed and you should only ever need to change this if you change the wheel circumference in the bosch unit itself.

Darren.

DarrenR

Has this been tried with the Teves MK60? I know of a few people - me included - who are using or will be using the Teves MK60 as a standalone.

Thank you for your time!

-

Trever

You'll need a development package or at least a custom partner package to get any CAN data from the MK60. The current "off the shelf" packages only support the Bosch messaging.

It wouldn't be hard to get the messages from the MK60 though, the addresses are known.