Discussion
My wife has a typical, modern VW-group 7 speed wet clutch dual clutch transmission on her car and, whilst on the move at least, I can't really fault the way it operates.
However, at low speeds it can be a little jerky and most particularly at sub-creep speeds. And that makes perfect sense to me, as when edging into a space at 1mph, the brake and clutch are basically battling each other in some misguided and very unsuccessful attempt to simulate a torque-converter. It all feels rough and mechanically unsympathetic.
But it go me thinking. I'm sure that the early examples of sequential manual transmissions did not bother with any notion of 'creep', merely sitting in first with the clutch fully depressed until the driver pushed the throttle to move away. I'm talking about Ferraris and Aston Martins in the late 90's/early 00's here, but also potentially some normal cars like Fiats etc. (didn't they do one with a 'clutchless' manual??)
I can totally see that as mainstream manufacturers started to replace the torque converter in regular cars with a DCT, which happened increasingly towards the late 00's, market research would suggest the sort of people who liked little cars with autos wanted something indistinguishable from the torque converter they're trading in.
But is this (creep) actually the best mode of operation in a DCT and do any manufactures still offer a DCT without creep? Were the SMT cars without creep even more of a pig to drive slowly? I recall Clarkson raging about the Vanquish gearbox, but that's Clarkson...
In fact, do any offer the choice, as it's surely just a software change to enable or disable? (albeit, with a whole lot of expensive development to get there)
However, at low speeds it can be a little jerky and most particularly at sub-creep speeds. And that makes perfect sense to me, as when edging into a space at 1mph, the brake and clutch are basically battling each other in some misguided and very unsuccessful attempt to simulate a torque-converter. It all feels rough and mechanically unsympathetic.
But it go me thinking. I'm sure that the early examples of sequential manual transmissions did not bother with any notion of 'creep', merely sitting in first with the clutch fully depressed until the driver pushed the throttle to move away. I'm talking about Ferraris and Aston Martins in the late 90's/early 00's here, but also potentially some normal cars like Fiats etc. (didn't they do one with a 'clutchless' manual??)
I can totally see that as mainstream manufacturers started to replace the torque converter in regular cars with a DCT, which happened increasingly towards the late 00's, market research would suggest the sort of people who liked little cars with autos wanted something indistinguishable from the torque converter they're trading in.
But is this (creep) actually the best mode of operation in a DCT and do any manufactures still offer a DCT without creep? Were the SMT cars without creep even more of a pig to drive slowly? I recall Clarkson raging about the Vanquish gearbox, but that's Clarkson...
In fact, do any offer the choice, as it's surely just a software change to enable or disable? (albeit, with a whole lot of expensive development to get there)
Trying to reverse a CVT uphill into a parking space, perhaps when trying to get the back wheel onto the kerb to rotate the rest of the car in, could be quite a hair-raiser in some cars. You'd never know if the car was going to override the simulated 'creep' and give you full-blown acceleration since it obviously didn't know what you were trying to make it do.
Does is judder at all when pulling away in 1st gear? I have a Qashqai with a DCT and once it's in 2nd gear onwards it's absolutely fine, but pulling away on occasion it judders, not all the time but it's more noticeable uphill, I was told getting something called a clutch recalibration can be done to sort it, if it's anything like what i have then i can understand the frustration, as mine is only just coming up to 5 years old with 53k mileage.
The DSG in my 7.5 Golf GTi TCR was nice and smooth and very similar to a ZF8, the creep function on BMWs MDCT was a bit of pain as you had to tap the pedal to engage it which is not something you wanted to do in tight situations, I had SMG in an e46 M3 too long ago to recall that much but tight low speed parking could be a pain.
James_33 said:
Does is judder at all when pulling away in 1st gear? I have a Qashqai with a DCT and once it's in 2nd gear onwards it's absolutely fine, but pulling away on occasion it judders, not all the time but it's more noticeable uphill, I was told getting something called a clutch recalibration can be done to sort it, if it's anything like what i have then i can understand the frustration, as mine is only just coming up to 5 years old with 53k mileage.
No judder and I did have it serviced (including oil change) about 5k miles ago. You can tell when it's stone cold as the first few 1st to 2nd changes aren't the smoothest, but it's much better than manual cars I've had in the same conditions.No, this is specifically about how it feels when the brakes and the clutch are somewhat juggling for supremacy. To put it another way, I would not want to park it right up against a wall with less than 6 inches clearance as I think it'd risk jerking right into it.
Compared to a manual, or the silky ZF 6 speed I had before, where the speed is pretty much infinitely variable down to sub 1mph, it just feels clunky at these crawling speeds.
Edited by SweptVolume on Monday 2nd March 11:39
SweptVolume said:
But is this (creep) actually the best mode of operation in a DCT and do any manufactures still offer a DCT without creep? Were the SMT cars without creep even more of a pig to drive slowly? I recall Clarkson raging about the Vanquish gearbox, but that's Clarkson...
I think the V12 Vanquish gearbox was an 'ASM' box (Auto Shift Manual). I had one. Clarkson was right.Hill starts were tricky and even the simplest manoeuvre would make the car smell very clutchy. I thought it was awful.
I have a car with PDK and it's a much better system. It does creep if you want it to, I've not found it to be an issue.
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