[Tiki]

I received my MCS last week and I'm not quite understanding the DTC and how it works. I understand there is the toggle switch but what exactly does that engage/disengage?

The manual suggests that when you toggle it and get the skid light with OFF and the TRACTION warning on the speedo display turning on that means the DTC is on...which seems counter-intuitive for me, I've had a few moments when i've lost traction with it both on and off so I wanted to know if any of the smart kind people here may be able to shed some light on this?

 

[kenl]

There are three settings. DSC on (the default). Press once DTC on. Press and hold DSC off.


My limited understanding is that DTC is only to help you pull away in snow or situations like that. It allows some slip of the front wheels to get you going rather than just cutting the power when wheels pin is detected.

Best to leave the stability control on. If you are in a situation that could lead to an "off" having the traction control on can really help you as it can brake individual wheels to get you back on line.

I would only turn DSC off if on a track or trying to time 0-60s etc.

 

[lawrothegreat]

When you start the car, DSC is automatically on. In this mode the traction control mode is far more intrusive but effective than you might think. However as with all traction control systems, the more interference you have, the less wheel spin you'll have and the car ends up being fractionally slower.


Press the traction control toggle once and you engage DTC, Dynamic Traction Control. This is a version of DSC and as Ken says allows some wheel slip. In most situations this will probably be the quickest mode for the car. Whilst it's designed for loose surfaces it enables slightly quicker launches on tarmac than straight DSC.


Once you're in DTC press the toggle down for a further 5-6 seconds and you disengage the traction control system but the electronic differential is active, so the car can still brake individual wheels under acceleration, but this mode is the least intrusive. If you've got a manual then the rev match feature also disengages (and you realise how effective it is normally). This mode is great for coming off roundabouts at low speed in second gear under full acceleration but you will wear the tyres......

 

[kenl]

Great post lawro...

I miss the reduced effect of engine braking with the rev match.

 

[Tiki]

Great information from you both thanks very much!

 

[olires]

Can anyone tell me what exactly the rev matching function is or does?

 

[kenl]

The rev matching function is a trick of the F56 engine management system.

When you change down from say 4th to 3rd it takes a second or so for the engine to get to the correct revs for the speed of the car in that gear.

For example, if you are doing 40 mph in 4th the engine may be at 3000 rpm. If you change down to 3rd the engine revs at that speed may be 4000 rpm. During this period you will find that the engine brakes the car as it is catching up. In old school driving, you were taught to use engine braking to help slow the car and not just the brakes.

With rev matching, as you are changing gear the car brain predicts what rpm will be right for the car at that speed in that gear. So, as soon as you have lifted the clutch the engine has already spun up to the correct rpm. The effect of this is smooth, not jerky, down shifts.

I hope that makes sense?

 

[olires]

Oh, awesome explanation kenl. Thank you, I understand now!

Oli

 

[andyross37]

Ken - Thank You

I read the handbook several times and couldn't quite understand it all.

Your explanation was spot on and now I understand completely!

 

[Tony83]

I have a question

Is The ECDL (electronic differential) always active or only in DTC OFF or DSC mode?
Thanks