Dual Clutch Transmission vs. Conventional Automatic

[Ws6]

I really like my mazda cx5 auto. Best one I've driven. It isnt as crisp as a DCT or as fast but its plenty crisp and quick and very direct. It only unlocks the tq converter under 10mph, otherwise keeps it locked. Very efficient and very "direct". Fill for life. I took my last one to 106k miles and it was fine. I've seen used fluid analysis from 75k mile units and it shows similar wear as a regular auto at 25k miles. Mazda nailed it.

I drove a maserati with zf8 and while it doesnt feel as direct, it's also a very good gearbox, also very dependent on tuning and used in some vehicles that get the latter all wrong, sadly. Drove a 370z auto, it sucked. Drove an auto c6 vette, and it was pretty solid. Didnt really beat on it much though.

 

[Ws6]

It is perfect example that transmission is as good as company is willing to pay for it.
Getrag supplies dual clutch to Ferrari and BMW.
Now, dual clutch is more complex and requires more sophistication. Big problem is that it cannot haul a lot, and to sustain huge torque it becomes ridiculously expensive. ZF makes probably best dual clutch, PDK, but price is forbidden fruit to everyone but Porsche. Getrag is close second.
So, question is why? Why if ZF8 exists that can take all the torque, hp, haul anything, and be most reliable transmission? And, it is so fast that you, driver really cannot see difference between dual clutch and ZF8.

Zf8 is very good, but not at all in the league of a DCT for feel. Performance on a clock, etc? Sure. But having driven both, you can absolutely tell, and tangibles matter in luxury segments.

 

[pezzy84]

We have a VW TDI in our stable currently ('11 TDI Sportwagen) and my departed '12 TDI Sportwagen was also DSG.

Except for some takeoff lag when starting from a complete stop due to the computer modulating the clutch for a smooth start they were actually very nice gearboxes, you could barely even perceive the shifts happening as they were that smooth even under WOT. VW pretty much worked out all the kinks in the 6 spd DQ250 DSG way back in early 2000's when it was introduced mainstream and these have proven to become very reliable.

 

[edyvw]

Zf8 is very good, but not at all in the league of a DCT for feel. Performance on a clock, etc? Sure. But having driven both, you can absolutely tell, and tangibles matter in luxury segments.

Yeah, it is more, how I would say, deliberate. I owned DSG, I know how they behave. But, other than that, there is no case to be made for them. We are at the point where we are talking now difference in shifts of some 0.020-0.030sec.

 

[slacktide_bitog]

DCT fanboys brag about 15ms shift times but then sneer at a CVT with 0ms shift times

 

[Skippy722]

DCT fanboys brag about 15ms shift times but then sneer at a CVT with 0ms shift times

CVT: the official transmission of “I want the absolute numbest driving experience ever!”

 

[TiGeo]

DCT fanboys brag about 15ms shift times but then sneer at a CVT with 0ms shift times

And see how those CVTs react to adding 100hp when you tune them. It's not all about shift time.

 

[edyvw]

DCT fanboys brag about 15ms shift times but then sneer at a CVT with 0ms shift times

I will take GM 3 speed. Thanx.

 

[Eddie]

I'll take my MAZDA Skyactiv automatic. Soothe and quick shifting with lock up in all forward gears. ED

 

[sloinker]

Chrysler Torqueflite 727, GM Turbo 400 Ford C6 are the best torque converter transmission's ever built. Ford E4OD and the Focus DCT along with the Nissan CVT are the worst. People that are used to driving traditional transmissions are confused by DSg's. There is a learning curve and you need to think of the brake as an off switch.

 

[OppositeLocK]

CVT: the official transmission of “I want the absolute numbest driving experience ever!”

A properly set up one is theoretically the best transmission. F1 used to use them before they got banned. I have one of the old school ones in my Nissan (before they added the fake shift points) and I love how it stays at redline during WOT. Extremely efficient.

If you don't want numb get a manual. An automatic is by definition numb.

 

[Skippy722]

A properly set up one is theoretically the best transmission. F1 used to use them before they got banned. I have one of the old school ones in my Nissan (before they added the fake shift points) and I love how it stays at redline during WOT. Extremely efficient.

If you don't want numb get a manual. An automatic is by definition numb.

All the ZF8 equipped vehicles I’ve driven have been far from numb, every CVT I’ve driven has been numb. The Altima was a little less numb than say a Caliber, but still numb.

 

[OppositeLocK]

All the ZF8 equipped vehicles I’ve driven have been far from numb, every CVT I’ve driven has been numb. The Altima was a little less numb than say a Caliber, but still numb.

That's actually a good thing as it means it's so seamless you don't even notice it.

Depends on the vehicle and application. What vehicles are you comparing the Altima to?

 

[Skippy722]

That's actually a good thing as it means it's so seamless you don't even notice it.

Depends on the vehicle and application. What vehicles are you comparing the Altima to?

I shouldn’t say every CVT... the Kia Forte felt great to drive. The Altima/Rogue/Juke have a little bit of a rubber band effect, but the simulated shifts felt okay. The Calibers both had positively horrific rubber band effect and were absolutely numb. The Subaru we test drove wasn’t bad.

But yes, depends on the vehicle and application. The vehicles my wife and I like are not good candidates for CVT’s.

 

[Rand]

ZF trannys are pretty bullet proof, but in top of that smooth and quick.

That sounds like someone who doesnt have a zf 9-speed equipped vehicle

I too am a zf fan.. esp their 8-speed used in rams and grand cherokee

but the 9-speed as designed is a turd..

Can start with the fact that its designed for small car with small tires.. cant even use 9th gear in the cherokee.

 

[Driz]

I will take GM 3 speed. Thanx.

when did you ever see one of those die that wasn’t hammered mercilessly by a teenager? before that there was the 2 speed power glide . Nothing sexy but what it took to kill one was amazing!

 

[wemay]

Regular AT

 

[OppositeLocK]

That sounds like someone who doesnt have a zf 9-speed equipped vehicle

I too am a zf fan.. esp their 8-speed used in rams and grand cherokee

but the 9-speed as designed is a turd..

Can start with the fact that its designed for small car with small tires.. cant even use 9th gear in the cherokee.

The 9 speed in the Cherokee is made by ZF? Color me surprised. The one I drove had a terrible tranny. Slow, sloppy shifts, and the upper gears were useless.

But the ZF8 in my Ram is nothing other than excellent. Only way it could be better is with even faster shifts.

 

[Skippy722]

The 9 speed in the Cherokee is made by ZF? Color me surprised. The one I drove had a terrible tranny. Slow, sloppy shifts, and the upper gears were useless.

But the ZF8 in my Ram is nothing other than excellent. Only way it could be better is with even faster shifts.

Yep. I steered my parents well away from anything with that 9 speed. I believe Honda uses it as well.

I do agree with the Ram’s ZF8 programming being more geared towards smooth, the 845RE (8hp45) that was in my 300 was programmed to be more sporty.

 

[Tomioka]

Allison 6AT for the win in medium duty applications. Eaton tried to get in the medium duty market with their Procision DCT 7 speed but didn't gain popularity.