Traction Control

[bob]

I have just spent a few days trying to get the traction control to work as I expected it to work. I have found the traction control is not for performance and is for safety. If you are like me, I fit a aftermarket ECU as I want my engine to make more power and car to accelerate faster.

There are two types of traction control safety and performance. Factory traction control which is found on many cars is the safety type. This is why most people are not interested in traction control as they do not see it as a performance advantage. I have a lot of experience with performance traction control. Once you have experienced this type you are a believer.

My experience comes from using the Autronic traction control, which was developed with the assistance of Larry Perkins for the V8 Supercars in the late 1980's. It was eventually banned due to the advantage it gave.

I have asked that the Link/Vipec traction control to be fixed so it is the performance type, but have found no one in management is interested as they have more important things to do. I am hopping others will add to this request.

I will give you an example as to why the traction control does not make the car accelerate as fast as possible..

The way the Link/Vipec works is to rely heavily on ignition retard to reduce power to reduce wheel spin. It also will cut injectors, but from the "recommended" settings the only three cylinders would be cut on a six cylinder.  

The Autronic uses injector cut from one to maximum cylinders. It also warns you not to use ignition retard with turbocharged engines, as turbocharger and engine damage could occur. Very true fact...

The recommended settings given to me for the Link/Vipec are,

Ignition Retard Start -5 deg
Ignition Retard End -20 deg
Injector Cut Start 0%
Injector Cut End 40%
Proportional Gain 5
Integral Gain 0.3984
Derivative Gain 0  

The Autronic has just two settings. These are slip threshold and control range. There is one of these for every gear. There are no other settings to tune.

Slip Threshold :
        Percentage of allowable wheel slip before traction control commences reduction of engine power.

Control Range:
       Engine power will be reduced progressively over this slip range until all power is cut at range limit.
 
Slip threshold is the secret to performance traction control.  Example,

We have two cars, both the same except for the ECU. One has Autronic the other Link/Vipec. The Autronic has a slip threshold of 6% and a control range of 4%. Total of 10% slip. The Link/Vipec has 10% in the sip table.

We are on a road where the bitumen gives us a 6% slip. The car with the Autronic is at full power and accelerating. The car with the Link/Vipec has applied at least -5 deg retard and cut at least one cylinder. The car with the Autronic is making full power and putting all of it on the road. The Vipec is trying to deal with 6% slip and killing the power. Even if the slip was 10% the Autronic is providing 6% less slip.

The Autronic works to give the maximum acceleration. The Link/Vipec works to stop the wheel spin at the cost of acceleration.
 

[Simon]

Hi "Bob"

We endeavor to take all feedback onboard. But with all things tasks have to be prioritized.

We feel we have a working and effective traction control.

However if we find there are people that feel improvements can be made or that what is offered is not up to expectations as time passes we will make improvements.

 

 

 

[bob]

This is a potlical reply I expected.

"We feel we have a working and effective traction control".

"We endeavor to take all feedback onboard. But with all things tasks have to be prioritized".

The truth is the traction control is even worst then what I stated. It is only effective if you have the same road traction conditions. If you are on road with less traction your settings do not work the same. The Autronic will always give you the slip threshold no matter how the traction conditions change. If the Link/Vipec was an "effective" safety traction control it would give you consistent results. It does not. It is unsafe, and I would not rely on it.

I will make some logs to show just how "ineffective" the traction control is.

[Ducie54]

Curious to see the logs with different PID settings.

[mapper]

Edited after reading throug manual: 

 

Bob have you tried different PID Settings? if you like you can also turn ignition off and deal only with fuel cut. Similary to Autronics. 

The problem you see are that the controll range of the PID is just to narrow, since the threshold for slip is at the same time the target slip. So the Closed loop system tries to hold the target to close and cut to much power, isn't it? And maybe jumps to much from lets say 10% cut to 90% back and forrward?

Have you tried different PID settings? 

Realy like to see your loggs!

I feel the better variable than %slip is how fast the wheel spins relativ to the ground. So delta of wheelspeed to vehicle speed. 

Usually putting lower numbers in at higher gears does that. But why the indirection if we can put in deltaspeed, would make delta speed not make more sense than % slip?

Edited January 12, 2016 by mapper

[AXA]

ANY UPDATES?

[muzzytt]

ANY UPDATES?

Yeah I would like some info on this too I don't want to go to all the hassle of connecting it up to find it's not what I was expecting

[mapper]

Any updates?