| Motoring Discussion > Skoda Roomster - Understanding DSG boxes | |
| Thread Author: Manatee | Replies: 16 |
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Mon 16 Jun 14 10:29
Skoda Roomster - Understanding DSG boxes - Manatee
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We have now had the Popemobile (Roomster 1.2TSI 105ps 7 speed DSG Scout, to give it its full pedigree) for a week or so and it is Good. A corker in fact. Slightly numb in D, but the changes are barely perceptible on a light throttle. It comes alive in S, when the shift point moves up to nearer 3000rpm and it gets much better at changing down when slowing, though I suspect that knackers the economy. More noticeable in S are the precision automatic throttle blips on the downchanges. Very nippy, the turbo giving full torque from 1500rpm, smooth, quiet, and easy to drive. My wife commented on just how easy in fact, which implied that she drives it exactly as she does the Civic 1.6 auto (slush box). That had me thinking about the 'right' way to use DSG. For example - the book of words says not to hold it on the accelerator (or creep) on a hill. The reason seems clear, which is that the mechanical, multi dry plate clutch is then slipping. That would be OK on the slush box, which is just churning fluid. Point being they are not the same, even though they can be driven in the same way. Getting proper guidance on this is not easy. I have observed that it appears to back the clutch off from the biting point when the brake pedal is pressed. It also has hill hold. For the uninitiated, hill hold operates when the car is in gear and the brake is released, on a hill >5%. The brakes stay on for 2 seconds, or until the accelerator is pressed. So hill starts are pretty clear. Use the footbrake, firmly pressed, and allow the hill hold to do its stuff. But what of waiting at traffic lights/junctions? Footbrake again? Or handbrake and neutral? The clutch does NOT appear to disengage when the handbrake is applied, so staying in D with handbrake on is a no. Reversing up hill into drive? It is easy to reverse in on the creep/a touch of accelerator. But that is functionally similar to hold on the accelerator on a hill. Perhaps better to drive in, and reverse out with the slope and an occasional touch of brake? I'd really like definitive information on how the thing works. What this thought experiment has made me wary of is buying a used DSG, especially in a hilly area. I've also found an ex-demonstrator for my uncle - fortunately only 2,000 miles on the clock. I doubt very much if anybody gets instruction on how to drive these properly when they are given a service loan car, which I suspect this "demonstrator" might have been. Advice welcome. |
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Mon 16 Jun 14 11:21
Skoda Roomster - Understanding DSG boxes - Boxsterboy
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I don't think there any specific twin-clutch auto driving instructions. We've got 2 - a VW DSG and a Ford Powershift and neither FM mentions anything in particular. In traffic I hold it on the footbrake, unless I know I'm there for a while, in which case it's handbrake on and slip into neutral. Both our 'boxes have hill-hold, so it's the same on hills - hold it on footbrake - there's no need to try and hold it on the accelerator. The only think I'm unclear about is 'box fluid change. |
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Mon 16 Jun 14 11:56
Skoda Roomster - Understanding DSG boxes - WillDeBeest
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Would be interesting to learn more about this, because it sounds as if there's scope for correct or incorrect use to affect durability, possibly significantly. So if I'm thinking of buying a used DSG, what do I need to know? I probably assume that it's been used in the minimum-input style, stuck in D and held on the footbrake - just as most drivers drive any automatic, in other words. So if that's the case, do I need to worry more about premature wear than I would with a TC? I suspect I do. |
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Mon 16 Jun 14 14:19
Skoda Roomster - Understanding DSG boxes - idle_chatterer
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Right, my two cents..... I have the DQ200 DSG in a Golf VI Twincharger - the worst possible combination according to the naysayers. I'd add that you cannot get a manual derivative here in Australia. And yet... it's lovely to drive, very smooth and snappy changes will creep like a TC auto and a great balance of performance and economy . The much heralded recall was for the electrics, or more accurately the synthetic oil in the mechatronic units could in certain circumstances (hot climates mostly) corrode the circuitry in the mechatronic unit causing spurious errors (not what you want in a major control system). The fix is new mineral oil or a new control unit in some circumstances. My car never required this as it was built after they discovered the problem although (bizarrely) some models built after mine (possibly VIIs even) had the wrong oil in them. However, the DQ200 (in 1.2TSi, 1.4TSis and 1.6TDis) is dry clutch for lightness and fuel efficiency. It has two clutches in fact - one for odd gears and the other for the even ones (as do other DSGs of course). In 'D' (rather than 'S' ) the ECU programming tries to change up from the ultra-low 1st as soon as it can, the result is that it slips the even-gear clutch quite a lot and they can overheat, that is what the manual refers to about creeping in traffic. With your foot on the footbrake the gearbox is in neutral, take it off and it will creep by slipping the clutch. I drive mine with minimum input but I am mindful of the fact it's a clutch and not a torque converter, therefore I stand still in traffic until there is room to move rather than creeping along. The DQ250 and DQ500 are designed for higher power and torque and the clutches run in a bath of oil (wet clutch), this is less fuel efficient but less prone to overheating. I understand that both the ECU programming (that loves to change up for economy) and the dry clutch packs have been modified over time due to problems with clutch plates warping. All covered under warranty and dependent on build date I think Last edited by: idle_chatterer on Mon 16 Jun 14 at 14:24
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Mon 16 Jun 14 14:34
Skoda Roomster - Understanding DSG boxes - Boxsterboy
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Yes, I understood that when stationary the gearbox was in neutral, and as such there is no wear on any of the 'box (unlike say with a TC where you can feel the engine strain at the leash). As you release the foot-brake a switch engages the clutch, hence the slight delay that some people complain about. I find the VW 'box better than the Ford 'box in this respect, and really -to me - the delay is both minimal and acceptable.
Last edited by: Boxsterboy on Mon 16 Jun 14 at 14:34
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Mon 16 Jun 14 14:36
Skoda Roomster - Understanding DSG boxes - idle_chatterer
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The handbrake has no effect on the DSG - exactly the same as in a manual car (where the clutch does not disengage when you put the handrake on). To be clear, your DSG is in neutral whilst: Lever is in N Lever is in P (when the transmission is also locked) Footbrake is depressed You can use any of these in traffic but most people I know just use the footbrake. See my other post on 'not' creeping quite like a TC auto. It has a clutch (2 actually), when you manoeuvre in 1st or reverse you are slipping a clutch just like in a manual. The ECU programming on mine means it is very controllable and 'feels' like a TC auto and will creep on the idle jet. |
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Mon 16 Jun 14 15:03
Skoda Roomster - Understanding DSG boxes - rtj70
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>> The handbrake has no effect on the DSG - exactly the same as in a manual car (where the >> clutch does not disengage when you put the handrake on). >> To be clear, your DSG is in neutral whilst: Maybe it makes a difference if the car has a normal handbrake or an electronic one. When I demo'd a 1.4TFSI Audi A3 with the S-Tronic gearbox, putting the handbrake on (electronic) must have put the gearbox into neutral because it was not straining against the brakes or anything. The Golf also has an electronic parking brake - so might that not be a difference in how to use these DSG equipped cars? And I decided to order mine without hill hold. That's great on a manual car (VWs anyway) but for manoevering with a DSG, touch the brakes and hill hold is engaged. Yes it can be turned off but kind of defeats the point of having it. Last edited by: rtj70 on Mon 16 Jun 14 at 15:05
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Tue 17 Jun 14 02:45
Skoda Roomster - Understanding DSG boxes - idle_chatterer
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>> >> And I decided to order mine without hill hold. That's great on a manual car >> (VWs anyway) but for maneuvering with a DSG, touch the brakes and hill hold is >> engaged. Yes it can be turned off but kind of defeats the point of having >> it. >> The last car I drove with an electric handbrake was an A4 B8 manual 6 years ago so I can't comment on whether it disengages the DSG clutch, I guess that logically it would. My car has a manual handbrake and hill hold, I've had hill hold on manuals before (330d) and it took some getting used to. On my current DSG vehicle it never gets in the way, it merely stops you rolling backwards for about 1s after the footbrake is released. I cannot recall it ever intervening whilst maneuvering even in reverse going up hill and to be honest I'm not sure I'd like a DSG vehicle without it. Hill hold is standard fitment on all DSG VWs (which is pretty much all of them) in Australia and you cannot delete the option. |
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Tue 17 Jun 14 05:30
Skoda Roomster - Understanding DSG boxes - Manatee
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>> to be honest I'm not sure I'd like a DSG vehicle >> without it. Hill hold is standard fitment on all DSG VWs (which is pretty much >> all of them) in Australia and you cannot delete the option. >> based on what I have found so far, I agree. I had already guessed that hill hold must be standard now with DSG in the interests of clutch preservation, given how most people drive in the real world and how few open the manual unless they have to. |
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Tue 17 Jun 14 05:54
Skoda Roomster - Understanding DSG boxes - Manatee
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Incidentally, I'm not sure it's ever truly in neutral, even when the lever is at N. One source I can't find now says that while in N, 1st and reverse are both selected on separate shafts (1,3,5,7 being on the same shaft, and 2,4,6,R on the other), and then according to which is selected, the appropriate one of the two associated clutches will engage when the brake is released. Presumably then if D is selected, the preselection for the even gear clutch will change from R to 2, ready for the upchange. Last edited by: Manatee on Tue 17 Jun 14 at 05:55
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Tue 17 Jun 14 08:58
Skoda Roomster - Understanding DSG boxes - idle_chatterer
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>> >> Presumably then if D is selected, the preselection for the even gear clutch will change >> from R to 2, ready for the upchange. >> Yes, that is why the changes are so fast - the next gear is always preselected on the upchange at least. In my description I shouldn't have used 'neutral', I suspect that a gear is often preselected but the clutch(es) are disengaged e.g. when stationary with your foot on the brake. I guess in 'N' or 'P' it truly is in neutral with no gear preselected. In fact, following through my thought process, if you put the car in 'N' in traffic there is a delay (not huge but detectable) when moving off that you don't get having held the car on the footbrake. This behaviour is somewhat akin to putting a TC auto into 'N', there is a subsequent delay then when the thing spins up the TC etc and the 'feel' is pretty similar IMHO. However it is in this circumstance that the DSG vehicle is more like a manual, only someone with no concern for clutch life would hold a manual car on the clutch constantly rather than selecting neutral, whilst the VW DSG will drive like a TC auto and 'creep' it is perhaps a little unwise to do this constantly. |
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Tue 17 Jun 14 09:13
Skoda Roomster - Understanding DSG boxes - idle_chatterer
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It might be clear that I actually rather like my DSG, I doubt that this technology will be 'going away' any time soon, remember that manual transmissions are not very popular in many markets these days. I suspect that several million VAG group customers may have completed their product testing for them, there have been many improvements in the software and engineering of these boxes which date back to the Porsche PDC more than 10 years ago (I think). I cannot fault the economy of my car, it manages 50mpg on a run and 30-33mpg on the urban runaround, not bad for a car with 160PS. Petrol is much cheaper in Australia though, the 98RON my car likes is about 88p/l at the moment and the locals think it's expensive ! |
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Tue 17 Jun 14 09:35
Skoda Roomster - Understanding DSG boxes - rtj70
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Hill hold is certainly not standard on VAG DSG cars - it might be on VWs? It's not on the Audi A3 that's for sure. The A3 with S-Tronic gearbox not only disengages the gears when you're stationary (slipping the clutches?) but when Drive Select is in Economy mode, lift off the accelerator and it goes into coasting mode with revs dropping to idle. I'm expecting fair economy when I get one later this year. I am sure around town etc it will be better than my current and previous diesels. On a run it will be similar I would imagine. |
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Tue 17 Jun 14 16:47
Skoda Roomster - Understanding DSG boxes - Manatee
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>> Hill hold is certainly not standard on VAG DSG cars - it might be on >> VWs? It's not on the Audi A3 that's for sure. I had extrapolated from (a) the fact that HH is a standard feature on the cheapest Roomster with DSG, and (b) the obvious benefit in the potential to save the odd-gear clutch. Seems odd not to include it throughout the group's products when it must be a zero marginal cost software feature, and cheeky to charge £75 plus VAT for it. Maybe that's for the switch, I don't think it's switchable in the Roomster. >> >> The A3 with S-Tronic gearbox not only disengages the gears when you're stationary (slipping the >> clutches?) but when Drive Select is in Economy mode, lift off the accelerator and it >> goes into coasting mode with revs dropping to idle. Vorsprung to the past! I don't think the Popemobile does this in D, though it might as well for all the retardation it gives, using the highest possible gear almost all the time. The only car I had with a freewheel feature was a 1977 Saab 96 - I only pushed that handle once, and hoiked it back out again sharply after frightening myself, and the brakes, down a long hill! |
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Tue 17 Jun 14 23:34
Skoda Roomster - Understanding DSG boxes - bathtub tom
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>> The only car I had with a freewheel feature was a 1977 Saab 96 - I only pushed that handle once, and hoiked it back out again sharply after frightening myself, and the brakes, down a long hill! You should've tried it on an ancient Rover 75 back in the '70s. I was given one as a 'favour'. Did a few few jobs on it that I thought would satisfy the MOT test. Took it to my favourite MOT place that required a drive that included a long downhill stretch, the brakes weren't too hot. Scared doesn't begin to describe it! |
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Tue 17 Jun 14 11:13
Skoda Roomster - Understanding DSG boxes - Boxsterboy
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>> It might be clear that I actually rather like my DSG, I doubt that this >> technology will be 'going away' any time soon. >> I like my DSG too, and agree that they won't be going away any time soon. The reason they (and, sadly, CVTs) will replace TC autos is because they can achieve lower emissions, which is the Holy Grail. |
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Tue 17 Jun 14 14:29
Skoda Roomster - Understanding DSG boxes - idle_chatterer
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>> >> I like my DSG too, and agree that they won't be going away any time >> soon. The reason they (and, sadly, CVTs) will replace TC autos is because they can >> achieve lower emissions, which is the Holy Grail. >> >> I understand that the US market now has an economical (sic) Golf derivative with the 1.8TSi with 170 or 180PS and a TC Auto, this would suit me fine in Aus where 95RON ULP is 80p/l and there are no downsides to the car's CO2 output. By comparison, the Corolla (Auris) comes with a single engine option of 1.8VVTi and TC Auto in Australia and they sell very well, I think the smallest engine in a Focus is a 2.0l petrol too. But over in Europe you need a 1.6TDi in a full-size estate car and 4x4s with only 2 wheel drive and diesel convertibles and DSGs etc etc. I'm coming over all un-reconstructed ! |
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