VAG DSG auto boxes

[ProfJohnL]

Its certain;y true that a CVT when properly controlled adjusted has the advantage on discrete gear ratios, as in theory the ECU should keep the engine at its peak efficiency conditions and adjust the CVT.

Historically however CVT's have failed to be attractive to the driving public, and I suspect it's been the apparent disconnection between engine speed and vehicle speed, often the engines have been running faster than drivers expect and this seems unnatural, so much so that some manufacturers actually programmed to transmissions to simulate shifting with fixed ratio's!

One of the major pressures on manufacturers has been to improve fuel efficiencies, CVT's theoretically offer an infinite number of gear ratios which does in theory mean the engine can be kept operating in its most efficient power band, but the public's distaste of the way CVT's operates forced manufacturers to look at increasing the numbers of fixed gear ratio's, which is why we often see cars with 6 or more forward gear ratio's ( I think one manufacturer introduced a 9 gear ratio box in some models) These keep the engines operating speed closer to optimum, but the down side is there are more gear changes to be made, so many of these boxes are semi or full automatics and the advent of the dual clutch systems like the VW DSG allow for some very slick systems where shifts are very fast and almost seamless.

DSG's and other similar boxes are proving to offer strong performance, but with so many additional parts in the boxes there are natural concerns about long term reliability. As previously discussed in the thread DSG's especially in their latest form are proving to quite reliable, even on high performance vehicles. so it seems that dual clutch boxes are becoming far more popular.

Where does this leave the CVT? It seem that some (usually smaller niche market) manufactures are trying to develop CVT's But until their reliability is seen to have been massively improved, it's unlikely they will unseat the fixed gear boxes with high numbers of ratio's. Also with the political pressure to move away from ICE, Manufacturers will be reluctant to invest in CVT's when there is a lot of knowledge and prior experience with fixed ratio boxes.

 

[otherclive]

Its certain;y true that a CVT when properly controlled adjusted has the advantage on discrete gear ratios, as in theory the ECU should keep the engine at its peak efficiency conditions and adjust the CVT.

Historically however CVT's have failed to be attractive to the driving public, and I suspect it's been the apparent disconnection between engine speed and vehicle speed, often the engines have been running faster than drivers expect and this seems unnatural, so much so that some manufacturers actually programmed to transmissions to simulate shifting with fixed ratio's!

One of the major pressures on manufacturers has been to improve fuel efficiencies, CVT's theoretically offer an infinite number of gear ratios which does in theory mean the engine can be kept operating in its most efficient power band, but the public's distaste of the way CVT's operates forced manufacturers to look at increasing the numbers of fixed gear ratio's, which is why we often see cars with 6 or more forward gear ratio's ( I think one manufacturer introduced a 9 gear ratio box in some models) These keep the engines operating speed closer to optimum, but the down side is there are more gear changes to be made, so many of these boxes are semi or full automatics and the advent of the dual clutch systems like the VW DSG allow for some very slick systems where shifts are very fast and almost seamless.

DSG's and other similar boxes are proving to offer strong performance, but with so many additional parts in the boxes there are natural concerns about long term reliability. As previously discussed in the thread DSG's especially in their latest form are proving to quite reliable, even on high performance vehicles. so it seems that dual clutch boxes are becoming far more popular.

Where does this leave the CVT? It seem that some (usually smaller niche market) manufactures are trying to develop CVT's But until their reliability is seen to have been massively improved, it's unlikely they will unseat the fixed gear boxes with high numbers of ratio's. Also with the political pressure to move away from ICE, Manufacturers will be reluctant to invest in CVT's when there is a lot of knowledge and prior experience with fixed ratio boxes.

Toyota hybrids and Honda too have been CVT fir

Its certain;y true that a CVT when properly controlled adjusted has the advantage on discrete gear ratios, as in theory the ECU should keep the engine at its peak efficiency conditions and adjust the CVT.

Historically however CVT's have failed to be attractive to the driving public, and I suspect it's been the apparent disconnection between engine speed and vehicle speed, often the engines have been running faster than drivers expect and this seems unnatural, so much so that some manufacturers actually programmed to transmissions to simulate shifting with fixed ratio's!

One of the major pressures on manufacturers has been to improve fuel efficiencies, CVT's theoretically offer an infinite number of gear ratios which does in theory mean the engine can be kept operating in its most efficient power band, but the public's distaste of the way CVT's operates forced manufacturers to look at increasing the numbers of fixed gear ratio's, which is why we often see cars with 6 or more forward gear ratio's ( I think one manufacturer introduced a 9 gear ratio box in some models) These keep the engines operating speed closer to optimum, but the down side is there are more gear changes to be made, so many of these boxes are semi or full automatics and the advent of the dual clutch systems like the VW DSG allow for some very slick systems where shifts are very fast and almost seamless.

DSG's and other similar boxes are proving to offer strong performance, but with so many additional parts in the boxes there are natural concerns about long term reliability. As previously discussed in the thread DSG's especially in their latest form are proving to quite reliable, even on high performance vehicles. so it seems that dual clutch boxes are becoming far more popular.

Where does this leave the CVT? It seem that some (usually smaller niche market) manufactures are trying to develop CVT's But until their reliability is seen to have been massively improved, it's unlikely they will unseat the fixed gear boxes with high numbers of ratio's. Also with the political pressure to move away from ICE, Manufacturers will be reluctant to invest in CVT's when there is a lot of knowledge and prior experience with fixed ratio boxes.

I’d hardly call Toyota,Nissan or Honda niche manufacturers. All have been using CVT on hybrid, conventional orfull electric models for many years now. The Toyota Prius has an excellent reliability record even when used as a taxi too.
Subaru have had CVT since around 2008 and mine has three selection modes when I’m Auto as opposed to Manual. One mode is eco which is seamless CVT. Second mode is Sport with seamless CVT but the turbo boost increases and revs at a particular road speed are increased. Sport I* takes it a step further and puts the engine into eight preset ratios. With paddle shifters and manual mode too it has a lot of flexibility but I tend to leave it in Eco mode as it is quite smooth and relaxed yet still retain good acceleration too.

The link shows some examples of CVT cars

Category:Vehicles with CVT transmission - Wikipedia

en.m.wikipedia.org

 

[ProfJohnL]

Toyota hybrids and Honda too have been CVT fir


I’d hardly call Toyota,Nissan or Honda niche manufacturers. All have been using CVT
hybrid, conventional orfull electric models for many years now. The Toyota Prius has an excellent reliability record even when used as a taxi too.
Subaru have had CVT since around 2008 and mine has three selection modes when I’m Auto as opposed to Manual. One mode is eco which is seamless CVT. Second mode is Sport with seamless CVT but the turbo boost increases and revs at a particular road speed are increased. Sport I* takes it a step further and puts the engine into eight preset ratios. With paddle shifters and manual mode too it has a lot of flexibility but I tend to leave it in Eco mode as it is quite smooth and relaxed yet still retain good acceleration too.

The link shows some examples of CVT cars

Category:Vehicles with CVT transmission - Wikipedia

en.m.wikipedia.org

I stand corrected. There are more CVT's than I anticipated, but they are still a minority, though that might change.

 

[Buckman]

Audi have had a CVT gearbox for long time. Our 1996 Corolla 1300 has a CVT gearbox and changes are very smooth. No excessive revving at all! Hardly a niche market.

 

[ProfJohnL]

Audi have had a CVT gearbox for long time. Our 1996 Corolla 1300 has a CVT gearbox and changes are very smooth. No excessive revving at all! Hardly a niche market.

I would be very worried if a CVT didn't produce a smooth change, as they are supposed to offer infinite ratio between their maximum and minimum limits, and that by definition should mean smoth ratio transits.

I'd agree that with modern engine management systems excessive revving ( that is likely to damage the engine or transmission) should not happen. But I have driven a Ford Bmax CVT and traveled in other models where it was my impression the engine does runat higher RPM than I would have liked for the speed and load of the car.

Perhaps I'm not up to date with engine performance characteristics, but the level of engine noise in these cars was not as good as I would expect from similar models with fixed ratio boxes.

CVT market share is still very small, and I strongly suspect as we approach the UK Governments no ICE car sales deadline the need and money for further developing CVT's will dry up in the UK.

 

[otherclive]

I would be very worried if a CVT didn't produce a smooth change, as they are supposed to offer infinite ratio between their maximum and minimum limits, and that by definition should mean smoth ratio transits.

I'd agree that with modern engine management systems excessive revving ( that is likely to damage the engine or transmission) should not happen. But I have driven a Ford Bmax CVT and traveled in other models where it was my impression the engine does runat higher RPM than I would have liked for the speed and load of the car.

Perhaps I'm not up to date with engine performance characteristics, but the level of engine noise in these cars was not as good as I would expect from similar models with fixed ratio boxes.

CVT market share is still very small, and I strongly suspect as we approach the UK Governments no ICE car sales deadline the need and money for further developing CVT's will dry up in the UK.

But CVT are used extensively in hybrid or FEV so there will always be further developments to improve performance, economy and reliability. After all FEV are forecast to require minimal servicing and should have long lives. Bad luck on the motor trade !

 

[Firkle]

Dusty, back to your original question.

I have a 2 year old VW Tiguan SE NAV with the 150 bhp diesel and 6 speed DSG.

To date it has done 30K miles, of which approximately 8 K have been towing a 1500 kg MTPLM caravan and it has behaved impeccably. It also usually averages 29-30 Mpg whilst motorway towing at 60.

 

[xtrailman]

I've only towed 1 year with my 187 bhp Tiguan, it rated to tow 2300 kg with a 7 speed DQ500 DSG and 4 motion.

I can't detect any difference towing 1700 kg compared to my previous CX-5 TC auto 175 ps rated to tow 2000 kg.

You do need to use the auto hold for hill starts though or the car will roll back, that's the only downside....

 

[otherclive]

I've only towed 1 year with my 187 bhp Tiguan, it rated to tow 2300 kg with a 7 speed DQ500 DSG and 4 motion.

I can't detect any difference towing 1700 kg compared to my previous CX-5 TC auto 175 ps rated to tow 2000 kg.

You do need to use the auto hold for hill starts though or the car will roll back, that's the only downside....

Doesn’t it have a handbrake then?

 

[Firkle]

Doesn’t it have a handbrake then?

Clive,

When the DSG is put into park it puts the permanent handbrake on, which is then released when you select either forward or reverse.

When driving normally the auto hold acts as an automatic handbrake, engaging when you stop and disengaging when you press the accelerator to drive off.

Auto hold can be switched off but I normally drive with mine switched on to get the full functionality.

 

[xtrailman]

Clive

Sorry i don't understand why you would ask if the Tiguan has an handbrake seeing you own a VW?

 

[otherclive]

Clive

Sorry i don't understand why you would ask if the Tiguan has an handbrake seeing you own a VW?

I don’t own a VW. I have a Subaru Forester XT. My previous car was a Skoda Superb 4x4 estate DSG. It had a handbrake and Hill Start Assist. I sold it on account that even being under 50k miles it’s lack of reliability was a big disappointment and with an undiagnosed vibration under load I decided to part company and return to Asia.

 

[xtrailman]

I see.
To explain most new cars Mazda cx-5 and Tiguan for two have auto hold and a handbrake, in practise with a VW you never need to use the HB as its automatically selected when auto hold turns off.
Auto hold uses hydraulics to brake all four wheels when the engine is running, reverting to a electro mechanical HB that uses the rear wheels only when the engine is off, or when the engine is still running but you exit the drivers door.

I just leave mine in auto and let the car do the rest.

 

[Stig]

A conventional Auto would get my vote personally.


Henry "stig"

 

[Stig]

I see.
To explain most new cars Mazda cx-5 and Tiguan for two have auto hold and a handbrake, in practise with a VW you never need to use the HB as its automatically selected when auto hold turns off.
Auto hold uses hydraulics to brake all four wheels when the engine is running, reverting to a electro mechanical HB that uses the rear wheels only when the engine is off, or when the engine is still running but you exit the drivers door.

I just leave mine in auto and let the car do the rest.

Left foot braking would be a good alternative to using the electric handbrake,
sit it on the brake with your left foot and leave you right one for the accelerator!

 

[otherclive]

Left foot braking would be a good alternative to using the electric handbrake,
sit it on the brake with your left foot and leave you right one for the accelerator!

Doesn't it still apply the auto hold anyway unless you can cancel it in the cars settings?

 

[Woodentop]

I see.
To explain most new cars Mazda cx-5 and Tiguan for two have auto hold and a handbrake, in practise with a VW you never need to use the HB as its automatically selected when auto hold turns off.
Auto hold uses hydraulics to brake all four wheels when the engine is running, reverting to a electro mechanical HB that uses the rear wheels only when the engine is off, or when the engine is still running but you exit the drivers door.

I just leave mine in auto and let the car do the rest.

On a VW the auto-hold drops into full HB after about 2-3 minutes, presumably to counteract any drop in hydraulic pressure.
Once you have VW auto-hold you never want to go back, and certainly it makes caravan towing so much less stressful. You just have to remember to turn it off when you go through the car wash (IMO tunnel variety) or the car behind might bump you!

 

[xtrailman]

Why bother complicating a automatic braking system by using two feet.
Just put it in auto hold and forget about it.