Front wheel speed sensor location

[Hector]

I know you all went through this question a few years back, and Scott explored a lot of elegant solutions, just wanted to know what the latest and simplest solution may be . I have the standard suspension and front hubs and rotors, I am using the Graziano unused front wheel shaft as my engine speed sensor and I need a front wheel speed (which provides the actual vehicle speed signal to the traction control unit). My son helped me clean up the racetronics controller with a new 3D printed case and new button circuitry instead of the removable faceplate and will mount directly to the dashboard , the only thing I am missing now is the front wheel speed sensor location. It is an M8 1.0 thread sensor and needs to be 0.062 inches or less from a metal surface.
Thanks for your help.

 

[Joel K]

Hector, I assume you need it on the front wheels and not on the rear axle?

 

[Ken Roberts]

I originally used the back of the wheel studs to get a signal. See my post #413 on page 21.

I have since upgraded to the SKF X Tracker hubs and have a new solution at the machine shop currently. It’s a removable reluctor wheel. (It will only work with 30 spline X Tracker hubs though).

 

[Hector]

Hector, I assume you need it on the front wheels and not on the rear axle?

yes I need one on the front wheels and not the rear axle

 

[Hector]

I originally used the back of the wheel studs to get a signal. See my post #413 on page 21.

I have since upgraded to the SKF X Tracker hubs and have a new solution at the machine shop currently. It’s a removable reluctor wheel. (It will only work with 30 spline X Tracker hubs though).

Thanks Ken, I remember seeing your set up before, I just could not find it, my search skills need to improve. I think I will go that route.

 

[Scott]

I am using the Graziano unused front wheel shaft as my engine speed sensor

I'm not familiar with the Graziano, but I don't see how the front wheel shaft helps you with "engine speed". I assume that you're referring to RPM and to get that you would need to know what gear you're in so that you could take into account the effective gear ratio (i.e., actual gear * drop gear, etc.). Perhaps you mean driveshaft speed?

Counting wheel studs isn't an ideal solution. That will result in 5 pulses pre revolution and most relocators that I've seen have 50 or more. So, you're providing approximately an order of magnitude lower frequency than what all of the OEM and aftermarket solutions that I'm familiar with use. A fair number of SL-Cs have been totaled at relatively low speeds (e.g. exit ramps, city streets, etc.) and at those speeds you already have a lower frequency. So long as the traction control unit can handle it, more pulses is better.

There is now an upgrade path to install better hubs in the front and the rear. They provide embedded OEM-quality reluctors (they aren't suspetiale to dirt), better durabilty and significantly less knockback. IMO you should consider upgrading the hubs. If not, I'd machine a reluctor... that was my plan until I found a way to install better hubs.

 

[Ken Roberts]

Hector is using Racetronic Traction Control which compares front and rear wheel speed and a brake module that runs inline to the rear brakes. If the unit senses slip then it brakes the rear wheels briefly.

I completely agree with Scottt.The higher the resolution the better. That’s one of the reasons I upgraded the wheel hubs.

 

[Hector]

I'm not familiar with the Graziano, but I don't see how the front wheel shaft helps you with "engine speed". I assume that you're referring to RPM and to get that you would need to know what gear you're in so that you could take into account the effective gear ratio (i.e., actual gear * drop gear, etc.). Perhaps you mean driveshaft speed?

Counting wheel studs isn't an ideal solution. That will result in 5 pulses pre revolution and most relocators that I've seen have 50 or more. So, you're providing approximately an order of magnitude lower frequency than what all of the OEM and aftermarket solutions that I'm familiar with use. A fair number of SL-Cs have been totaled at relatively low speeds (e.g. exit ramps, city streets, etc.) and at those speeds you already have a lower frequency. So long as the traction control unit can handle it, more pulses is better.

There is now an upgrade path to install better hubs in the front and the rear. They provide embedded OEM-quality reluctors (they aren't suspetiale to dirt), better durabilty and significantly less knockback. IMO you should consider upgrading the hubs. If not, I'd machine a reluctor... that was my plan until I found a way to install better hubs.

yes driveshaft speed compared to front wheel speed, OK I get the frequency issue, I will look into that. Thank you Scott . I will need to figure out how to make the signal compatible to my traction control unit