Filed under: Economy, Tech, Hatchbacks, Volkswagen
VW to debut 7-speed DSG at end of year
Porsche originally pioneered a working version of the dual clutch gearbox concept on some 962 Group C cars in the late 1980s, but it took until 2003 for the design to show up in production vehicles. When Volkswagen introduced the six speed DSG in various Audi, VW, and Skoda models, it used dual wet clutches in a setup designed and built by Borg-Warner.
The DSG has half the gears connected to one clutch with the other half connected to the second clutch. It works essentially as two interwoven gearboxes tied to a single output. As one clutch is engaged, the other is disengaged and shifted. When it's time to go up or down a gear the corresponding gears on the open clutch are coupled and the two clutches swap positions. At that point the gears on the opposite are coupled in preparation for the next shift.
This year, Volkswagen is introducing a new-generation DSG with an extra gear and dry clutches. The new seven-speed gearbox is more compact than the original and more efficient thanks in part to the dry clutches. Because of its smaller size, the new box can be used in models all the way down to the Polo. VW will start building the new gearboxes late this year and they will appear in the Golf with the 1.4L TSI gas engine and the 1.9L TDI diesel. The 1.4L TSI is also new, and like VW's other TSI engines uses direct fuel injection but uses only a turbocharger rather than the twin turbo/supercharger setup used on the other TSI mills.
[Source: VW]
PRESS RELEASE:
PIONEERING SEVEN-SPEED DSG GEARBOX BREAKS COVER
Volkswagen has developed an evolution of its pioneering DSG gearbox. The new seven-speed system – a world first and codenamed DQ200 – uses a pair of dry clutches in preference to the six-speed version's twin wet clutches. This increases efficiency and performance over the wet clutch six-speed system.
The six-speed DSG gearbox, which was introduced in 2003, uses a pair of clutches submerged in oil. The new seven-speed gearbox adopts a pair of dry, organic bonded friction linings that do not require cooling, making the drivetrain more efficient through the extra ratio and the fact that less power is required for the gear selection and clutch servo system.
For the first time the DSG gearbox has been mounted transversely. Measuring only 369 mm in length and weighing only 79 kg including the dual-mass flywheel the gearbox is remarkably compact. These modest proportions mean it can be applied to models from the Polo right up to the Passat and, in its current form, it is capable of coping with power outputs of up to 170 PS and 184 lbs ft of torque.
In adopting seven-speeds, Volkswagen engineers were able to lower first gear to improve acceleration from a standstill. By contrast seventh gear has been raised to act as an overdrive function making it ideal for motorway driving with the additional effect of raising economy and comfort levels.
The volume of oil contained within the gearbox has also been reduced by 75 per cent. The oil circuits are split into two in an effort to protect the lubrication's purity. As with a conventional manual gearbox, one of the circuits is used for cooling and lubrication of the gear teeth, the second feeds oil to the gear actuators. Since the clutch does not require cooling the quantity of oil was reduced from seven litres in the six-speed DSG gearbox to only 1.7-litres in the new seven-speed system.
Production of the gearbox is set to start at the end of the year with its first application in the UK being planned for the Golf and mated to the 1.4-litre TSI petrol and 1.9-litre TDI diesel engines.
NEW TSI TO REPLACE EXISTING 1.6-LITRE FSI UNIT
Volkswagen is also introducing a new turbocharged 1.4-litre engine to replace the existing 1.6-litre FSI engine. Based on the 1.4-litre TSI engine the new unit is not fitted with a supercharger and instead uses a sophisticated turbocharger. The result is an output of 122 PS linked to a choice of manual or DSG gearboxes.
The new engine is planned to be fitted to the Golf, Golf Plus, Golf Estate, Jetta and Passat models, replacing the current 1.6-litre FSI engine when production commences later this year.
Reader Comments (Page 1 of 2)
Rade 9:42AM (5/25/2007)
This is all great and fantastic news but can we start seeing this marvel of engineering outside of the B-segment? I know its due to the platform but we've been hearing the 997 DSG rumors forever and its yet to materialize...yeah i know "Wait for the refresh" only to be followed by, "Wait for the new one!" I guess I'm just impatient.
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tooler 9:50AM (5/25/2007)
Will it come to NA.?
The current 2.5L 5-cylinder engine in Jetta and Rabbit is a piece of s**t,
the cylinder block is cast iron, unbelievable!
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Mark 9:55AM (5/25/2007)
Ford has their version of the DSG coming out in 08/09. I can't wait to see it in the next gen Focus. Too bad the 2008 Focus will still have a 4 speed auto. :(
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Dondonel 10:08AM (5/25/2007)
So instead of adding a torque converter to cure the harsh shifts in low gears (especially from stop and at slow speeds), they went the other way and replaced the wet clutches with dry clutches. This will bring no fuel savings compared with a torque converter with lockup clutch in every gear, instead it will further decrease the realiability of the transmission and the clutch life. Enjoy it.
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james 10:56AM (5/25/2007)
a torque converter is one of the worst and most power sapping parts of a transmission. A DSG avoids them for a reason, as it is more of a conventional manual with automatic mode as opposed to a conventional automatic with manual mode. if you want slushy shit gearboxes that chew through petrol, stick with a torque converter based 'box
Alan44 10:48AM (5/25/2007)
"The current 2.5L 5-cylinder engine in Jetta and Rabbit is a piece of s**t"
Obviously someone who doesn't own one, my wife now has over 13,000 on her 06 Jetta with this engine and it is a nice quiet good running engine. It is really nice at high speed on rural interstates. Someone else mentioned rough low gear shifts on the six speed, I have never noticed this on this car.
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why not the LS2LS7? 10:50AM (5/25/2007)
The new DSG can handle even less power than the last? Is it trying to compete with CVTs for "most disappointing transmission technology"?
How about going the other way, to bigger motors? And if the dry clutch is all that, saving 5L (10 lbs) of oil, shouldn't even the current DSG be upgraded to save the weight?
I have to say I'm somewhat with Dondonel. Every time this thing shifts it shoves a lot of heat into the rather small clutches. By going to a dry clutch, that heat won't be removed as effectively, which means it'll stand a chance of burning up the clutches. This doesn't sound so great to me.
I do find the current DSG to be rather pleasing. A friend has it in his 4-door Rabbit GTI. It does have some minor driveline shuffle at times, but for the most part, it's very impressive.
But imagine that transmission in a higher-end vehicle, like a V8-based sports car. Vroom!
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bgdc 11:08AM (5/25/2007)
Shrug. Love the DSG in our A3. I won't give up my manuals but I still get a grin when I take out the A3...the DSG's instant shifts are so intoxicating.
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Quattrofan 11:20AM (5/25/2007)
Looks insanely complex. I'll take it with a 6 speed manual please.
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TDIMeister 11:44AM (5/25/2007)
"Looks insanely complex. I'll take it with a 6 speed manual please."
Manual transmissions are certainly models of simplicity and efficiency (most can achieve 95% or higher, untouchable by automatics and CVTs), but what can you see from the picture of the outside that makes DSG complex?
Only the mechatronic actuators inside are complex-looking. I know this because I was involved in a program bid by my employer to supply a component for it. I've worked with VW-supplied PRO-Engineer models and the result of my work is somewhere in Wolfsburg operating away in prototype testing.
But the hardware that transmits power from the engine to the driveshafts is not much removed from manual transmissions, in contrast to what you'd find in a traditional planetary automatic tranny.
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MikeW 11:49AM (5/25/2007)
This is for low torque diesel and gas engines.
250 meter-newtons, 184ft-lbs
The 2.5 is junky (variable intake manifold?, variable valve timing? 5800rpm redline), where is the twin-charger. Not just that, the gearing way too short, the 6th gear on the automatic should be tall, say 3000rpm=100mph.
The dry clutches reduce drag compared to wet clutches.
Harsh shifts? It all depends of the programming, and 1st gear is extra low for good low speed control (read:smoothness)
It could be programmed to more or less open the current drive clutch and then engage the second clutch, (less of a baton hand off where you have two hands on at the same time, and more like someone throwing the baton at you, you catch it and keep going)
this would not add any more heat to the clutch than a conventional stick shift, and then this has two clutches to distribute the heat over. (and the % engine speed drop is lower per gear change)
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Rocket Punch 11:50AM (5/25/2007)
Don't tell me I am the only guy who knows that a DSG gearbox is already in one of the mot powerful production car in the world. It is not just for the B-Segment, and please do not compare it to some sissy pants CVT technology (which is something thats in a 80's Subaru Justy.......)
Think.
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flying.cars 12:57PM (5/25/2007)
reminder: DSG is only licensed by VW. It was invented and manufactured by the american company borg warner.
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DriftPunch 12:59PM (5/25/2007)
No torque converter? I always thought it had a species of one simply to 'squish' it off the line and to lessen the impact of shifts.
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Fabulo 1:08PM (5/25/2007)
Wow, 7 speed DSG in my mum's Polo! Wow! That will unleash its 60HP!
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bgdc 2:18PM (5/25/2007)
No torque converter at all in a DSG. It's a manual, folks. A complex computer controlled one but still a manual.
And the Veyron uses a DSG...so it's not like DSG's can't be beefed up to handle anything.
Finally, Mitsu is releasing the next Evo with a dual-clutch DSG-like tranny. BMW has supposedly been prepping one for 08 or 09 too. They're dropping their SMG for the DSG-style.
And DSG's are uber-smooth and insanely fast shifting. Sequential Manual's aren't as fast or as smooth. DSG's shift so quickly and seamlessly that many people get confused when using one and accidentally shift 2-3 times in a row (cough...my brother-in-law).
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Dondonel 3:12PM (5/25/2007)
bgdc, DSG is by no means a manual, don't fall for VW's marketing nonsense. A manual transmission is a transmission in which you can manually change gears through a mechanical link. There is no way to do this with DSG, even though DSG is made out of two intermeshed manual gearboxes. Therefore DSG is not a robotized manual (like SMG), it is an automatic transmission of a different kind, in that it does not use planetary gearsets. From the late 30's when DSG-like gearbox was proposed for the first time, it was labeled as an automatic transmission.
By the way, I did my share of driving in a DSG VW and I can reassure the people that never went further than a test drive that DSG is nowhere as smooth as an automatic. And yes, this is because it lacks a torque converter.
DSG is just a good implementation of a poor idea. It survived on the market place through smart marketing. Its only quality is that is shifts fast, but it is inconsistent in the way it shifts. Any departure from the driving habits of an 80 years old lady and it will preselect the wrong gear, resulting in hesitation and longer shifts than the new generation of automatics. In addition to this it is just as heavy as an automatic gearbox and much weaker (like any manual transmission). Yeah, it was used on Veyron, I'm sure one can built whatever, when cost is no object.
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Don 6:13PM (5/25/2007)
I'm not sure how the 2.5-litre 5 is "junky".
Not only does it offer up ample power, but it's obviously low tech and reliable.
Everyone wants a screaming 2.0-litre Evo. Pfft.
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AMcA 10:07PM (5/25/2007)
Torque converters are no longer inefficient.
It was back in the mid-'80s that they started adding lock-up devices. And they've gotten better at it.
Has anyone else noticed that some cars are getting better numbers with automatics than with manuals these days?
Uh huh.
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GotDiesel 11:38AM (5/29/2007)
Uh.. no,... havent seen an auto getting better than my 50 MPG average ( 75..80 MPH Freeway ) Jetta TDI..