After Market Traction Control

[Tabulous]

Just wanting to run this past you guys. Been thinking about designing and building my own traction control system. Now been an Electronics/Software Engineer it should not be that hard.........

I know racelogic makes one but to be fair the price is very steep. I'll be lookin at £200 max to develop this prototype.

I'll do it as a protype first, got the basic design on paper, with all the required signalling requirments, just about.

Was just wanting to ask what your thoughts are on power reduction methods. I.e.

1 - Cutting Injector signal thus cutting fuel supply.

2 - Cutting Spark signal thus cutting ignition.

Both ways have issues,

1 - Cutting fuel can lead to lean burning, which we all know is bad, but if you cut the fuel by around 50% then the air/fuel ratio is so that the mixture will not ignite. And even if it did there would by insuffience mixture to create any substantial power.......

2 - Cutting Spark can cause bore washing with the unburnt fuel running down the sides of the cylinders and washing the oil coating away, thus provocking more rapid cylinder wear......

So let me know your thoughts

Regards

Lee

[Bobby-H]

Just wanting to run this past you guys. Been thinking about designing and building my own traction control system. Now been an Electronics/Software Engineer it should not be that hard......... 

I know racelogic makes one but to be fair the price is very steep. I'll be lookin at £200 max to develop this prototype.

I'll do it as a protype first, got the basic design on paper, with all the required signalling requirments, just about.

Was just wanting to ask what your thoughts are on power reduction methods. I.e.

1 - Cutting Injector signal thus cutting fuel supply.

2 - Cutting Spark signal thus cutting ignition.

Both ways have issues,

1 - Cutting fuel can lead to lean burning, which we all know is bad, but if you cut the fuel by around 50% then the air/fuel ratio is so that the mixture will not ignite. And even if it did there would by insuffience mixture to create any substantial power.......

2 - Cutting Spark can cause bore washing with the unburnt fuel running down the sides of the cylinders and washing the oil coating away, thus provocking more rapid cylinder wear......

So let me know your thoughts

Regards

Lee

←

I think the usual way of doing it is to cut the fuel completely for a very short time so that is misfire is caused in one cylinder. You might need to tap into the crankshaft position sensor to make sure you cut the fuel at the right time.

[Tabulous]

Would have thought that the fuel injector pulses would be ok.........dont realy need to know the crank position. Just count the injector pulses, there should be 4 per cycle, and cut out the pulses as and when required. Making sure to rotate the cyclinders i.e. change the cyclinder each time, so a different one is cut.

[boundsw]

The racelogic setup cuts the fuel, i know that for sure as a mate of mine has it on his Supra TT (previously TT, now BIG T).

I guess Racelogic (Blitz) will have put alot of time and investigation into developing their product, so i would say thats the safer of the two options, although it does'nt seam ideal either way ?!!?

[Bobby-H]

Would have thought that the fuel injector pulses would be ok.........dont realy need to know the crank position. Just count the injector pulses, there should be 4 per cycle, and cut out the pulses as and when required. Making sure to rotate the cyclinders i.e. change the cyclinder each time, so a different one is cut.

←

Yes, its just like you said but the reason I say you need to tap into the crank shaft position is that if you let the fuel cut back in half way through an injector pulse you could get a very lean mixture in the cylinder and that could be bad news. Also, if you know the crank shaft position you know which cylinder will fire next so you will then know which injector you need to cut.

You could monitor the pulse at the ECU end and make sure you dont switch back in while the ECU is transmitting a pulse. You could work out which injector is next to fire because you would know which one fired last time so I suppose that would be a good way to do it too.

[PaulT]

Are you building that on an axle with a limited slip diff? If not, you might want to consider applying the brakes rather than cutting the throttle. No idea how you would get an interface to the brake circuits.

And how will you decide whether or not a wheel is skidding?

Plus, remember if you cut the fuel because the wheels lose traction when the car is stationary, the engine has to stall.

Paul.

[boundsw]

Also, with the idea of cutting the spark (Is this system going to be just for MR2's?) I know the 2 has a single wire from the ECU which is the ignition time signal (I know this as i have just fitted my ECU)

Other vehicles have a ignition wire per cylinder !

As said, reducing the fuel enough may create such a small explosion, that maybe it will be or no concern, but with a turbo, if big enough boost is being run????????????........

[Bobby-H]

Also, with the idea of cutting the spark (Is this system going to be just for MR2's?) I know the 2 has a single wire from the ECU which is the ignition time signal (I know this as i have just fitted my ECU)

Other vehicles have a ignition wire per cylinder !

As said, reducing the fuel enough may create such a small explosion, that maybe it will be or no concern, but with a turbo, if big enough boost is being run????????????........

←

Cutting the spark will be a bad idea if the car has a catalytic converter, pumping fuel in there will brake it.

[PaulT]

I wonder if the simplest option might be to hack the rev limiter and use whatever mechanism the car has built in to modulate the throttle. However, the response may not be fast enough, nor might it be able to cope with the rapid switching that you need in a traction control system wthout failure.

Paul.

[boundsw]

Also, with the idea of cutting the spark (Is this system going to be just for MR2's?) I know the 2 has a single wire from the ECU which is the ignition time signal (I know this as i have just fitted my ECU)

Other vehicles have a ignition wire per cylinder !

As said, reducing the fuel enough may create such a small explosion, that maybe it will be or no concern, but with a turbo, if big enough boost is being run????????????........

←

Cutting the spark will be a bad idea if the car has a catalytic converter, pumping fuel in there will brake it.

←

Dont know ? Racelogic do it ?