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Traction Control using abs sensors


Chemicalblue

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Well I guess Ill start by stating my idea...

 

I'm looking into using abs sensors to monitor and log wheel spin, and want to use my Haltech to pull timing to control the wheel spin.

 

Which would mean I could have push button traction control on my S130!

 

Doable?

 

I know I can modify a CV or use a cv's with the sensor gears on them and I think I can mount a sensor to read the gears, but the front wheel sensors are the real issue.

 

Does anyone have an idea on the best way to monitor front wheel speed?

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I think that it's an excellent idea and you're futher along in your plan than I am.;)

 

Is the main purpose to control a launch at the strip, or were you thinking of a full-on vehicle dynamics control? I'm still missing the point why you'd want to monitor front wheelspin...

 

[Edit: D'oh! You'd need to know front wheel speed to control the rear speed...excuse my brain fart, lol]

 

I was thinking more along the lines of using a rev limiter to control power versus pulling timing if was for the strip. I like the idea of pulling timing much better!

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wait why do you need to know if the front wheels are spinning? whether they are or not you cant do anything to make them stop. can you?

 

The point is to control the rears from over-spinning, but in order to do that you need to know if they are or not. An easy way to do this is to compare the velocity of the rears versus the fronts. They should be roughly equal if there is no wheelspin. The fronts should never lose traction in acceleration since we're rwd (of course).

 

A good way limit power for a turbo might be to use an electronic boost controller...

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I've seen this discussed many times over, haven't seen a real viable solution, because it takes a comparitor circuit to monitor all points of interest, and then decided how much differnce is too much and send this signal, what ever that may consist of (determined by your power controlling device, I.E. Haltech, ignition retard box, etc), to pull timing or power out based on how much wheel spin. If you wante dto get real trick, you could have a variable output (as long as the Haltech can support this), to pull more and more timing out if the initial isn't enough.

 

The discussions have also consisted of what should be monitored and the best seems to be RPM , some suggest drive shaft speed and a non-driven wheel as a base.

Depending on how sensitive the circuit is, just going around a corner could trip the circuit into thinking there is tire spin.

 

For montiring the front wheels, depending on how the S130 hubs and rotors are set up, you might be able to adapt a newer rotor that has a tone ring built in.

If it needs to be custom a tone ring could be made and then pressed onto the hub, into the rotor, or some sort of bolt in deal, that gets sandwiched between the hub and rotor, and places the tone ring close to the knuckle. Kinda like making a rotor hat from a very thin material, to then hold the tone ring.

 

One possible problem is if your car is able to pull the front wheels or take a LOT of weight off of them, this can slow the rotation of the wheels and then make it seem like the rears are spinning, even though they have excellant traction. I wonder if some sort of first gear disconnect would be benificial here.

 

Take a look into some aftermarket systems, you may find this to be a more viable solution.

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I've seen this discussed many times over, haven't seen a real viable solution, because it takes a comparitor circuit to monitor all points of interest, and then decided how much differnce is too much and send this signal, what ever that may consist of (determined by your power controlling device, I.E. Haltech, ignition retard box, etc), to pull timing or power out based on how much wheel spin. If you wante dto get real trick, you could have a variable output (as long as the Haltech can support this), to pull more and more timing out if the initial isn't enough..

 

That pretty much my thought.

If I tell the Haltech we want the back wheels to be able to spin 10% (or whatever #) more than the front, then no matter how fast the wheels are spinning the Haltech will be trying to balance the difference by pulling power if needed.

 

The discussions have also consisted of what should be monitored and the best seems to be RPM , some suggest drive shaft speed and a non-driven wheel as a base..

 

How else can you determine wheel speed?

 

Depending on how sensitive the circuit is, just going around a corner could trip the circuit into thinking there is tire spin.

 

This should be resolved by the computer seeing all 4 wheels so that it will see if there is a difference in speed left to right ver. front to back.

 

 

For montiring the front wheels, depending on how the S130 hubs and rotors are set up, you might be able to adapt a newer rotor that has a tone ring built in.

If it needs to be custom a tone ring could be made and then pressed onto the hub, into the rotor, or some sort of bolt in deal, that gets sandwiched between the hub and rotor, and places the tone ring close to the knuckle. Kinda like making a rotor hat from a very thin material, to then hold the tone ring.

 

This is the real issue - what material to make the ring out of and what adaptable sensors are easily used, probably some sort of GM part.

 

One possible problem is if your car is able to pull the front wheels or take a LOT of weight off of them, this can slow the rotation of the wheels and then make it seem like the rears are spinning, even though they have excellant traction. I wonder if some sort of first gear disconnect would be benificial here.

 

if I'm getting that much traction I wont need any TC at all... hehe

 

Take a look into some aftermarket systems, you may find this to be a more viable solution.

 

My Haltech is aftermarket?

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I still think it's do-able. I'm not sure the driveshaft idea would work if you run an open diff or to take into account cornering. It would add to the complexity, but I don't see how you would get around having to monitor both LF/LR and RF/RR separately unless you have a 50/50 diff.

 

You might be able to lower the ~10% difference and just account for hysteresis.

 

It would be really cool if a Wolf could be capable of controlling this. Since it can flip between two programs, it would be really easy to turn the traction control on or off with the flip of a switch.

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I think you can do it with a pair of 240sx ABS components and a pair of "arduino" boards. It uses pulse width modulation, I assuming. It can trigger when the pared boards compare wheel rotations of the front wheels and and if it goes too far out of a set ratio, then it tell the EMC to back off on the throttle.

 

The problem would be having the boards to talk to the EMC. I think that MS would have the best compatibility.

 

Maybe a third on the drive line somewhere for a "estimated" rear wheel spin reading.

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there are afternarket traction systems around, I've bee racking my brain trying to remember the one that looked simple and reported to work well.

 

Yes, like most other sensors GM would probably be the easiest to adapt. The tone rings only need to be of a ferrous (magnetic) type of metal, so steel or cast would work. For a custom application steel would probably be easiest to use. The GM sensors when pulled from the rigt application would be very easy to mount. I know the mid '90s Cavalier and Grand Ams had a simple ABS sensor that had one or two bolt holes on a fairly flat mounting surface, that looked quite easy to retrofit. I'm sure there would be others that would work as well.

 

It might be this one that I'm thinking of: http://www.racelogic.co.uk/

 

There are more similar systems out there.

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