Friday 25th May 2007

Seven speeds for VW's DSG 'box

VW evolve their DSG technology

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The six-speed DSG unit

Volkswagen has developed an evolution of its pioneering DSG gearbox. The DSG system in effect 'pre-selects' the next ratio, allowing for a rapid and almost seamless gear change when the driver selects the next gear.

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 is said to increase 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 drive train 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 just 79 kg – 7kg lighter than the six-speeder 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 with the aim of improving economy and comfort levels, especially on the motorway.
 
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.

[Fusion-Ed]

7 speeds for a 170ps engine. Why?!

[Road_Terrorist]

Fusion-Ed said:

7 speeds for a 170ps engine. Why?!

Well if you think about it a piss weak engine that is barely adequate for a lawnmower probably needs the 7 speeds a lot more than something like a Turbo Diesel V10 or a large capacity V8, which would probably be perfectly ok with even 3 or 4 speed gearboxes.

[Lone Granger]

it would be a lot easier upping the engine capacity in the first place - then fit a 5 speed DSG.......

[rimmer]

The new seven-speed gearbox adopts a pair of dry, organic bonded friction linings.
do you reckon that they will sell more of these gearboxes because it has the word ORGANIC in it?

[Ed.]

Lone Granger said:

it would be a lot easier upping the engine capacity in the first place - then fit a 5 speed DSG.......

But the way emissions based taxation is going smaller engines and lots of gears makes sense
(atleast in theory (the only place the new laws can hope to make sense ))

Hope nothing goes wrong with it though, tighter tolerences (reduced lubrication) are all well and good until a small problem wrecks a transmission.

Edited by Ed. on Friday 25th May 22:44

[Mr Whippy]

But seven distinct gears?

Better off with a CVT in rubber band mode or full auto for these type cars surely if all you want is peak performance in both acceleration and economy terms?

DSG has it's place, but I doubt cheaper cars will be it's place in 5 years when it's a £2k bill waiting to happen on a £4k car!

Dave

[busta]

the article said:

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 with the aim of improving economy and comfort levels, especially on the motorway.

Same reason we moved from 4 to 5 back in the eighties then 5-6 in the early noughties. Now they tell us that a small hatchback actually needs seven gears to be both nippy and economical? All they really need is a diet and a re-map!
And who needs a lower 1st gear anyway? The traction control will go bonkers everytime you pull away briskly in the wet!

The worst bit is you can't even skip gears with DSG. Otherwise if you stuck to odd numbers you'd have a nice leggy 4 speed, which in a nice toquey diesel hatchback would be quite nice!

[collateral]

184 ft lbs isn't much when you're talking diesels...there aren't going to be many applications for this

[sprinter885]

Fashion...that's all there is to it. I still say bring back the electronic overdrive-unless anybody out there knows a viable engineering reason not to.

Edited by sprinter885 on Saturday 26th May 10:42

[FesterNath]

First time mounted transversely? Don't think so...

[keith8357]

i drive the 6 speed dsg in a audi 2.0 tdi & must say untill you have lived with one you dont realise how good they are, its like having air-con then buying a car without it, its that good

[Skodaku]

Something not quite right with the numbers quoted. If this new DSG will only handle up to 184lb ft torque then it's a backward step from the current one which is mated to the 2.0 TDi PD engine producing 236lb ft in a whole range of VAG cars.

Any comments ?

[Kirsty5150]

That's basically what I thought. It won't survive long behind a TDI engine bigger than 1.5 L or so. If you could skip gears you'd probably find you never used all 7 anyway, so I find it all a bit pointless. I thought part of the reason for having 5th and then 6th speeds was due to the higher speeds cars were expected to sit at with relative levels of confort/engine revs. Ie in the 70's cars maybe sat at 60-70 for a fair part of the time, where 4 gears was enough, with overdrives were required. Now cars are expected to be able to 100 or so with similar, if not greater levels of comfort and noise. A 4 speed would either sit at that speed, but have 4 overly long gears, or go to 5 or 6 speeds to compensate.

[Lone Granger]

sprinter885 said:

Fashion...that's all there is to it. I still say bring back the electronic overdrive-unless anybody out there knows a viable engineering reason not to.

Edited by sprinter885 on Saturday 26th May 10:42

love it on my Stag!

[Fast Eddie]

Hey guys
I have a regular 140ps Passat diesel with the DSG box and it is a waste of money. Here's the issue. Regular change ups and downs are fine except when you approach something like a roundabout and slow down to about 20 mph. Seeing that the coast is clear you squeeze the throttle gently and nothing happens because the box is wondering which gear to select - now another car is approaching so you engage some more throttle and suddenly you've got 4000rpm on and the car takes off like a scalded cat. Transits can beat me away from the lights because its so slow to start from rest until its moving - then all is well.
It also has a sport option which is is so highly geared that you can make good progress around town but it revs its head off because it won't take the higher gear.
The dealer says " they all do that, its working perfectly, take it away."

[Craigy_97elise]

Eh... isn't this box by borg warner?

VW's engineers wouldn't do anything to it except select the ratios...

C

[anonymous-user]

Fast Eddie said:

Hey guys
I have a regular 140ps Passat diesel with the DSG box and it is a waste of money. Here's the issue. Regular change ups and downs are fine except when you approach something like a roundabout and slow down to about 20 mph. Seeing that the coast is clear you squeeze the throttle gently and nothing happens because the box is wondering which gear to select - now another car is approaching so you engage some more throttle and suddenly you've got 4000rpm on and the car takes off like a scalded cat.

In places where you think you may need to override it (e.g. roundabouts, overtaking)...why don't you?

[tstain]

always found dsg shifts quicker on petrol rather than diesel

[Mars]

Does no-one else think 79Kg for a gearbox that can take so little torque is a little excessive?

[Fast Eddie]

Good question Dod.
The box is auto ie it has the normal PRND, then it has the optional sport 6 ratio mode and to select this you pull the lever back to a position marked S for sport surprisingly and also there is a tiptronic function and to engage this you push the lever to the left and then move it forwards and backwards for higher or lower ratios. Now if you're talking on your hands free and consuming a Ginsters simultaneously it's all a bit too complex.
Cheers
Eddie