Advanced Driving Hub

It is rather like stopping on a hill. During the last phase of braking pedal effort is proportional to speed so is reducing as the car’s speed reaches zero. In a manual car, on the level, the car would stop smoothly just as the brake pedal is released. On a slope it would start to roll. The creep of the DCT is just like the effect of being on a slope. As Mike says, you need to feather, then apply firmly to hold the car, the new 4th phase. Judging the moment to increase pedal pressure will become the new skill that determines whether or not you get the smooth stop we all desire.

GTR1400MAN wrote:I don't know about other makes/models but my creep function doesn't stop for several seconds if you apply the handbrake!

Interesting, I've not played around with mine to notice. Since I've got an electronic handbrake (boo hiss) I generally don't bother and just sit on the brakes. (yes, I did feel bad about dazzling the driver behind, but this behaviour seems pretty universal now). I know you can drive off "through" the handbrake, but again that's unsympathetic (to me) and faffing around with waiting for the handbrake to release, selecting drive (which you have to jump back on the footbrake to do if you've gone into neutral) all takes too long. Maybe different at a level crossing where I know I'll be waiting for a few minutes and get plenty of notice about when to move off. Mind you, there I've noticed that going into Neutral seems to prevent the car doing start/stop.

Anyway, thanks for the tips and Jonquirk. Yes, I was thinking last night about the similarities between stopping downhill in a manual and on the flat in an auto.

Maybe the answer is just more practice. Let's hope it's allowed soon...

jont- wrote:Mind you, there I've noticed that going into Neutral seems to prevent the car doing start/stop.

Sadly there again seems to be several different implementations.

In mine, the stop/start will activate when stationary and having firm, constant, pressure on the foot brake pedal. If I then select neutral, apply the (manual) handbrake and release the pedal, the stop/start will remain activated keeping the engine off. Selecting drive will then fire the engine as I release the handbrake to pull away.

If I'm sitting just on the brake pedal, the engine will fire as you move your foot across to the accelerator ... though much too slowly for my liking and the car can move backwards a little if on a small incline. The car does have 'Hill Start Assist' BUT there's no light to say it has been activated, so pulling away without the handbrake can be a gamble. The incline detection seems suspect, or at least needing a real hill to activate. So yet again, I tend to drive it like a manual.

To be honest, every time I get in the car I press the "turn this crappy stop/start system off" button. It's way too intrusive. It is only there so the car can claim to be Euro4 compliant and up the paper spec figures for MPG. Euro4 is also the reason Renault give for not being able to permanently turn it off and it being reactivated every time you start the engine.

Having discussed these foibles, I love my DCT and won't be going back to a manual box (if any are still available when I come to renew). I will also probably switch to a DCT bike next time I change. (As an aside, DCT gets a lot of flack in the motorcycle world. "Not a real bike." "Might as well have a scooter." etc. Yet, mention a quick-shifter and they are in ecstasy. No-one wants to listen when you explain that a DCT does all a QS can do, and more, giving seamless acceleration way beyond what a QS gives.)

A lot depends on the vehicle system. I have a BMW as Mike says you can stop then apply the foot brake firmly to activate the start/stop then place it is N and the engine will remain in standby. Also if you are holding on the foot brake you can ease the pressure and restart the engine without creep and be ready to move off especially useful if going up hill.

jont- wrote:..... I don't like being in that position of "riding the clutch" (even if it's the car doing it) for longer than I can help. I would probably feel different about doing that if I had a traditional auto.

I guess one ought to know more about the clutch mechanism. I think many twin clutches use a wet clutch where nothing is wearing while the clutch is 'slipping'. I remember hearing that clutch life was an issue in early automated manuals, but I haven't heard of short clutch life for a long time.

I think I prefer traditional autos for the easier manoeuvering. But 'traditional' is a relative term - I have two cars with the ZF 8 gearbox, and it so responsive and snappy when used manually that there is little difference from a dual clutch.

waremark wrote:

jont- wrote:..... I don't like being in that position of "riding the clutch" (even if it's the car doing it) for longer than I can help. I would probably feel different about doing that if I had a traditional auto.

I guess one ought to know more about the clutch mechanism. I think many twin clutches use a wet clutch where nothing is wearing while the clutch is 'slipping'. I remember hearing that clutch life was an issue in early automated manuals, but I haven't heard of short clutch life for a long time.

I think I prefer traditional autos for the easier manoeuvering. But 'traditional' is a relative term - I have two cars with the ZF 8 gearbox, and it so responsive and snappy when used manually that there is little difference from a dual clutch.

Interesting, I'd understood that while the wet clutch lasted better and being multiplate was smoother at low speeds, it still has friction material. Off to do some reading...

Yes, the 8-speed ZF does seem to be universally lauded. I've only had a very brief drive of one (AFAIK) in a Giulia and it was very good, but I don't think it can give you the thump in the back of the deliberately badly tuned PDK boxes in sport mode

Wet clutches do wear. Ask any motorcyclist who has had to replace one.

The oil gives a smoother operation, cooling and tend to be less 'grabby' than a dry clutch but they still work by friction.

In DCTs clutch wear is down to how good/intelligent the software is and how intelligent the driver is. Hold it on a incline with the throttle or creep a lot in traffic and you will still kill the first gear clutch.

Just a thought for the OP: is it worth wearing shoes with a thinner sole, to give better feel of the brake pedal, while you work on this?

Horse wrote:Just a thought for the OP: is it worth wearing shoes with a thinner sole, to give better feel of the brake pedal, while you work on this?

I generally wear barefoot running shoes for driving already, not sure how I find something any thinner unless I go fully barefoot

jont- wrote:Yes, the 8-speed ZF does seem to be universally lauded. I've only had a very brief drive of one (AFAIK) in a Giulia and it was very good, but I don't think it can give you the thump in the back of the deliberately badly tuned PDK boxes in sport mode

I did some acceleration runs in my E92 M3 with a V Box. The fastest run was with the gearbox in the softest setting. In the sportiest setting , apart from the fact that the thump on upchanges threw the car offline, the acceleration curve showed a dip at each change where the power was artificially interrupted to create the thump. That was an early dual clutch box, newer ones may be different.

Incidentally, I have never tried launch control. I wouldn't drop the clutch at high revs in a manual so why would I want a computer to do that for me? My acceleration runs were from a rolling start.