DCT Complaints Thread

[MyThIc3LiTe]

Originally Posted by gambit293

I'm not sure I understand what you're saying here. Are torque converters much less efficient than dry DCMs? Even if that may be true in principle, I hardly think the Focus's DCM mileage performance is superior enough that we could thumb our noses at traditional automatics. Perhaps future DCMs will mop the floor with ordinary autos, but right now the Focus holds its own but that's about it.

Not only are torque converter equipped boxes less efficient, they are also poor performance options.

Even ZFs rather good 8 speed automatics pale in comparison to VWs 6 speed DSG or Fords 6 speed DCT, to say NOTHING about Audis, BMWs and Porsches 7 speed DCTs.

We can thumb our noses at torque converter autos because in any imaginable way they suck. Badly. They always have. With the obvious exception of the gearboxes fitted to cars like the 760i or A8...

In the future?

DCT boxes have been wiping the floor with automatics for years, the GTI has had one for a while and VW is a pioneer in bringing it to the masses. BMW has tackled the single clutch solution since the E46 M3 and E60 M5, same with Audi and their R tronic. Even the SMGs, once you got around the fact that even like the DCTs they sucked at low speed, would put a automatic to shame.

Slushboxes are the reason EVERYBODY who cares about performance thinks that they suck, and they aren't far from the truth.

DCTs and to an extend SMGs before them are nothing like automatics. They don't have that parasitic suck. They don't sap any power, they don't spoil the transfer of power.

If such gearbox solutions are good enough for supercars, high end makes and race teams I think the technology is good enough for us.

You'll notice that racing series like ALMS and FIA ACO never used automatics in their cars. They either had manuals or single clutch sequentials. Even now a majority of your endurance spec cars have switched over to some form of SMG/DCT unit, F1 went sequential as well. Because these kinds of gearboxes are track proven to be better and in the case of cars like the GTI are road proven to be better.

If you like the inherent suck of a slushbox, by all means spoil the car by picking one.

But if the choice came between an underpowered car with a DCT or a more powerful one with a auto, I'm picking the DCT because the auto sucks the life out of that car whereas the DCT works harder to make the most of it.

[kam327]

Originally Posted by gambit293

I'm not sure I understand what you're saying here. Are torque converters much less efficient than dry DCMs? Even if that may be true in principle, I hardly think the Focus's DCM mileage performance is superior enough that we could thumb our noses at traditional automatics. Perhaps future DCMs will mop the floor with ordinary autos, but right now the Focus holds its own but that's about it.

I too have wondered about the true economic benefit of the DCT. I laughed that Ford's own marketing materials touted the increased efficiency of the DCT compared to a 4-speed conventional automatic. Well of course the 6-speed DCT is going to be more fuel efficient than a 4-speed for obvious reasons.

If you look at user data on fuelly.com, the Focus is no more fuel efficient than the rest of the class, some of which have 4- or 5- speed conventional autos. But we have to admit that the Focus has the most horsepower of the class and seems to get on average the best acceleration. So maybe the tradeoff is that you get slightly better performance for the same mileage.

Then you have the Dodge Dart which has the most comparable engine to the Focus's in the class - a 2.0L 160hp unit. But with its conventional 6-speed tranny it gets only 24/27/34 EPA ratings compared to the Focus's 27/31/38. But the Dart is also significantly heavier.

Bottom line in the real world it's hard to find an apples to apples comparison to see if the DCT has a real performance/economy benefit. For now we just have to take Ford's marketing materials for what they're worth.

In any case, clearly the modern CVT results in a more fuel efficient car. Just look at the new Altima and Accord.

[awsimons]

Originally Posted by kam327

I too have wondered about the true economic benefit of the DCT. I laughed that Ford's own marketing materials touted the increased efficiency of the DCT compared to a 4-speed conventional automatic. Well of course the 6-speed DCT is going to be more fuel efficient than a 4-speed for obvious reasons.

I'm sorry but implying that a 6-speed transmission is more efficient than a 4-speed because it has "2 more speeds" is uninformed. An apples to apples comparison of two transmissions' highway gas mileage would require each to have the same gear ratio. So what's the gear ratio of the 6th gear in a 6 speed and what's the gear ratio of 4th gear in a 4 speed? If they were the same, you would easily see that the DCT is more efficient than the torque converter because the DCT isn't wasting energy moving a bunch of transmission fluid around.

[kam327]

Originally Posted by awsimons

I'm sorry but implying that a 6-speed transmission is more efficient than a 4-speed because it has "2 more speeds" is uninformed. An apples to apples comparison of two transmissions' highway gas mileage would require each to have the same gear ratio.

I'm not just talking highway, which is a limited view. I'm talking overall. The whole point of 6-speeds or more is to have gear ratio spacing optimized for a broader range of operating conditions and better efficiency. I've seen quotes of 3-5% savings in general just for having 6 gears versus 4.

ZF says their new 8-speed transmission has two big advantages: improved fuel economy and shorter gear steps between cogs, for quicker acceleration and smoother shifts. They claim it's 6 percent more fuel efficient than their old 6-speed.

Plus I remember my 4-speed Contour turning around 2800 on the highway. The Focus is a couple hundred less than that IIRC.

[TboneZX3]

Originally Posted by awsimons

I'm sorry but implying that a 6-speed transmission is more efficient than a 4-speed because it has "2 more speeds" is uninformed.

On the highway, yes. But not combined or city.

[suss6052]

Originally Posted by kam327

I'm not just talking highway, which is a limited view. I'm talking overall. The whole point of 6-speeds or more is to have gear ratio spacing optimized for a broader range of operating conditions and better efficiency. I've seen quotes of 3-5% savings in general just for having 6 gears versus 4.

ZF says their new 8-speed transmission has two big advantages: improved fuel economy and shorter gear steps between cogs, for quicker acceleration and smoother shifts. They claim it's 6 percent more fuel efficient than their old 6-speed.

Plus I remember my 4-speed Contour turning around 2800 on the highway. The Focus is a couple hundred less than that IIRC.

Due to the gearing the DCT equipped Focus is turning right around 2600 rpm at 70 mph where as the manual is nearer to 3000 rpm at 70 due to the 5th gear being much shorter than the DCTs 6th gear.

[revhigh]

Originally Posted by awsimons

I'm sorry but implying that a 6-speed transmission is more efficient than a 4-speed because it has "2 more speeds" is uninformed. If they were the same, you would easily see that the DCT is more efficient than the torque converter because the DCT isn't wasting energy moving a bunch of transmission fluid around.

I think it's patently obvious that a modern 6 speed auto is going to have lower high gear ratios than a 4 speed, so making the above statement is kind of condescending to the quoted poster.

Also, talking about how much more 'efficient' the DCT equipped Focus is, mileage wise, is also just tech talk. It's not proven in the real world as indicated by roughly 357 cars on fuelly, averaging 31.5 MPG with it's 'super efficient' transmission compared to the widely mocked 4 speed 'slush box' cars.

Even the lowly Corolla with it's 4 speed, cave-man like, antiquated 'slush box' that sucks ... gets exactly the same mileage as the Focus in the real world. So it's the 'package' ... the whole vehicle ... that matters for fuel efficiency ... we don't drive transmissions ... we drive cars. Granted ... the Focus is far more fun to drive than a Corolla, and it's faster, but it's no more efficient overall than 15 year old bulletproof, trouble free technology that 'sucks'.

If the Focus DCT is as efficient as it is because of it's DCT ... I'd hate to see what it would get with a 6 speed 'suck' auto ....

REV

[kam327]

Originally Posted by suss6052

Due to the gearing the DCT equipped Focus is turning right around 2600 rpm at 70 mph where as the manual is nearer to 3000 rpm at 70 due to the 5th gear being much shorter than the DCTs 6th gear.

Thank you. I remember my Contour turning around 2750 at about that speed on my numberous trips between New York and Michigan 10-12 years ago.

[kam327]

Originally Posted by revhigh

Also, talking about how much more 'efficient' the DCT equipped Focus is, mileage wise, is also just tech talk. It's not proven in the real world as indicated by roughly 357 cars on fuelly, averaging 31.5 MPG with it's 'super efficient' transmission compared to the widely mocked 4 speed 'slush box' cars.

Even the lowly Corolla with it's 4 speed, cave-man like, antiquated 'slush box' that sucks ... gets exactly the same mileage as the Focus in the real world.

I used to totally agree and still kinda do, but you gotta take into account the Focus's better perfomance than the competition, and in particular, the Corolla. The Focus probably averages a solid second to a second and a half quicker to 60. That performance comes at a price so the fact that it still matches or slightly beats the Corolla's fuel economy.... you gotta give the DCT some props for that.

Originally Posted by revhigh

If the Focus DCT is as efficient as it is because of it's DCT ... I'd hate to see what it would get with a 6 speed 'suck' auto ....

Just look at the Dart's abysmal EPA ratings with the similar engine to see that...

[revhigh]

Originally Posted by kam327

i used to totally agree and still kinda do, but you gotta take into account the focus's better perfomance than the competition, and in particular, the corolla. The focus probably averages a solid second to a second and a half quicker to 60. That performance comes at a price so the fact that it still matches or slightly beats the corolla's fuel economy.... You gotta give the dct some props for that.

i did !!!


just look at the dart's abysmal epa ratings with the similar engine to see that...

i don't know if i'd call it 'abysmal' ... But it sure should be better ...

revhigh