Did You Know?

I read an article on a website a few months back stating that the Ford Focus ST has an Electronic brake lock differential and a two stage traction control system.

After a good few months of testing it seems the Zetec S also has the two stage traction control system.

With ESP/traction control on if you spin the wheels the car will either cut power/break a wheel or do both.

If you press the ESP button so the light is still on NO engine power reduction will take place and the stability control is completely off however the TC system will now start to act as an electronic diff braking which ever wheel is spinning the most.

The article said this active upto 53mph and is more of a performance feature than anything else.

It's implementation is simalar to BMW where the Electronic Diff Lock works when the TC is switched off.

So onto the tests I did to verify this.

During the snowy conditions my car park was very very slippy with compacted snow and ice. I placed just one of my snow socks on the front left tyre but left the other tyre as normal on the compacted snow. I then turned off ESP&TC. Put my foot down and as expected there was no reduction in engine revs so I had to use my foot to moderate power.

Now the interesting bit. After a few seconds of nothing happening "the brake lock diff system kicked in" You could hear the grinding of the ABS on the spinning wheel and shortly after power was transferred to the wheel with the snow sock on and away the car went. Amazing stuff!

With it TC back on you could plant your foot and both engine revs and the occasional bit of wheel braking kicked in. Revs were firmly held below 2500 to reduce wheelspin.

Another way to test it is to turn your TC/ESP off. If possible plant one wheel on some slipply grass and the other on tarmac and floor it. You will hear the ABS kick in on the spinning wheel and the car should still move forwards as power is transferred.

Like wise pulling out of a junction with it off will normally trigger the BLD to kick in for a second or two.

So to round off, the brake lock system that seems to be on the Zetec S is not designed to improve cornering like VW's XDS but will help acheive good accelation where uneven levels of grip exist without reducing engine power.

Has anyone tested this yet? If not I would be greatful if people could back up my tests by doing their own.