Can some advise why 1.6 TDi gets 7-speed DSG and 2.0 TDi gets 6-speed DSG?

Also why does DSG reduce emissions in 1.4 TSi, but increase them in the TDi engines.

The 7 speed cannot handle as much torque as the 6 speed, that's why lower powered cars get them.

The six speed box SKoda use is needed as it has a higher torque handling capability. Re the differences in emissions - it'll be down to efficiency and perhaps gearing differences between the boxes.

My 177bhp Tiguan gets the 7 speed!

My 177bhp Tiguan gets the 7 speed!

Thats a different box that isnt available in the Octavia 3.

I think there is a new 7 speed wet clutch DSG which is capable of higher loading than the old dry clutch one (may have wet/dry the wrong way around).VW will have it, looks like Skoda doesn't get to play with it yet.

My 177bhp Tiguan gets the 7 speed!

The Octavia 1.8 tsi 180hp gets the 7 speed dsg (250nm)

The Octavia 1.8 tsi 180hp 4x4 gets the 6 speed dsg (280nm)

There are 2 different types of DSG box used in Skoda cars. The 7 speed has a dry clutch set up which only has an oil capacity of about 1.7 litres and is limited to 180nm torque input. The 6 speeder has a wet clutch set up and an oil capacity about 6 litres with a torque limit of 250nm. That is why there are different ones used, no point a big box in if it is not needed. That is also why the 1.4 TSI has better economy than the manual but the other way round with the bigger diesel engines. There is more drag from the wet clutch box which detracts from efficiency and economy.

Ian

I think there is a new 7 speed wet clutch DSG which is capable of higher loading than the old dry clutch one (may have wet/dry the wrong way around).VW will have it, looks like Skoda doesn't get to play with it yet.

I appreciate that this doesn't really help the OP much (and I've no idea if my car has a wet/dry/mixed box) but I've just checked the Tig and it has 380Nm of torque.

At least it gives you an idea of what to expect if VW cascade their tech a little.

Also why does DSG reduce emissions in 1.4 TSi, but increase them in the TDi engines.

An interesting question. I have read in the past that the 7 speed DSG's ratios are particularly suited to the 1.4 TSI, presumably allowing the engine to operate in it's optimum RPM for economy for more of the time compared to the 6 speed manual. If the ratios are suited to the 1.4 TSI then they are likely to not quite be in the same sweet spot on the 1.6 TDI.....hence the slightly higher emissions compared to the Manual transmission on this engine.

On the 2.0 TDI the answer to this question is easy......the 6 speed DSG used on the 2.0 TDI introduces extra mechanical drag due to the clutches being immersed in oil......this accounts for the increase in emissions on this engine compared to the Manual.

Countryboy is spot on, I think. The dry clutch is less lossy than the wet one.

They don't have one set of ratios for each type of gearbox, surely. The 6 speed manual in my 4x4 140 is differently geared to a 6 speed manual in a FWD 140, that's certain.

They don't have one set of ratios for each type of gearbox, surely. The 6 speed manual in my 4x4 140 is differently geared to a 6 speed manual in a FWD 140, that's certain.

They most likely do have the same ratios......in the gearbox at least. I think on the two applications you mention it is the final drive ratio that is probably different?

Edited 20 June, 201312 yr by booke23

The 7 speed gearbox is lighter, smaller and more efficeint that the wet 6 speed but it is limited to 250 Nm.

The 7 speed works better than manual on the old 1.8 TSI, 160hp version, where it was a mile or two per gallon better than the manual.

The 180 hp 1.4 twincharge only uses the 7 speed DSG so I do not know what the figures on a (6 speed) manual would do.

When you do neutral coasting in the 6 or 7 speed it really helps the mpg.

I have a couple of each boxes and much prefer the 7 speed dry clutched box but it should move to even more gears. VW have a 10 speed in R&D.

Countryboy is correct in theory, but has the torque figures wrong. The 7 speed dry clutch can handle 250Nm (engines up to 1.8TSI FWD), while the 6 speed wet clutch can handle up to 350-380Nm (engines up to the VRS engines).

The 7 speed wet clutch in the Tiguan for example is a different version and newer, it can handle up to 500Nm if I'm not mistaken.

There was another topic where all of this was stated already.

Countryboy is correct in theory, but has the torque figures wrong. The 7 speed dry clutch can handle 250Nm (engines up to 1.8TSI FWD), while the 6 speed wet clutch can handle up to 350-380Nm (engines up to the VRS engines).

The 7 speed wet clutch in the Tiguan for example is a different version and newer, it can handle up to 500Nm if I'm not mistaken.

There was another topic where all of this was stated already.

+1

the 7-speed wet dsg = DQ500.

the 6-speed wet dsg = DQ250

the 7-speed dry dsg = DQ200