[wassell2381]

My sister recently acquired a new A3 TDI and I've been trying to compare it with my 320d to see whats a better bang for your buck. I think we all know the answer but still.

Biggest thing i noticed was Audi's Twin Clutch S-tronic gearbox. IMO it seems to be miles ahead of the Steptronic in the BM's. The fact that it loses absolutely no momentum during gear changes really caught my attention. Although my cars gear changes are faultless, it still seems to, under full load, slip quite a bit going into higher gears.

On the other hand i believe the audi's/volkswagon's change through the gears too quickly, unless in sports mode. Perhaps this is to keep economy down.

Just wondering what every1's views were on BMW's choice to stick with the conventional Steptronic for so long? After all the DCT has been available on selected cars since the LCI model came out.

Hopefully when the F30's come out they will have the DCT's as Standard

[pcockley]

As I started reading I though you were comparing apples and oranges, with AT V S-tronic as you should be comparing it with the DCT.

As for why BMW still have At and DCT...... marketing ??? I for one waited for the 335 to start shipping with the DCT before I bought one. love that box

[wassell2381]

Originally Posted by pcockley

As I started reading I though you were comparing apples and oranges, with AT V S-tronic as you should be comparing it with the DCT.

As for why BMW still have At and DCT...... marketing ??? I for one waited for the 335 to start shipping with the DCT before I bought one. love that box

Yea not really comparing a Dual Clutch with a Dual Clutch. More just trying to work out why BMW have been so slow to introduce something that's going to bring them back to having the best of the best.

Ive heard the DCT's are wicked!!?

[purifyer]

Isn't DCT a bit of a bitch with tuned 335is? I remember reading they were having a lot of difficulties... can't remember what they were exactly

[pcockley]

Originally Posted by purifyer

Isn't DCT a bit of a bitch with tuned 335is? I remember reading they were having a lot of difficulties... can't remember what they were exactly

Can't comment on the 'is' but I can say I amm 100% happy on a tuned 335i. You get a dual 'sport' mode if you like. The standard sport plus you can slide the selector knob to s/m for sport shift/manual mode for even quicker shifts. Oh plus you get an extra cog

[Stuart@BMRAutowerkes]

I think the F30 is gonna run the 8speed auto (still a slushbox, not a DCT)... I've driven the 8speed in the F10 and it's a fantastic gearbox. Simpler and cheaper than a DCT and I can't fault it.

[_Rubicon_]

I have the DCT in my 09 335i and it's an awesome box. On e of the reasons I bought the car & it hasn't disappointed. Once driving a DCT-type box you will never buy a manual again!

[Jeef Beef]

Originally Posted by wassell2381

My sister recently acquired a new A3 TDI and I've been trying to compare it with my 320d to see whats a better bang for your buck. I think we all know the answer but still.

Biggest thing i noticed was Audi's Twin Clutch S-tronic gearbox. IMO it seems to be miles ahead of the Steptronic in the BM's. The fact that it loses absolutely no momentum during gear changes really caught my attention. Although my cars gear changes are faultless, it still seems to, under full load, slip quite a bit going into higher gears.

On the other hand i believe the audi's/volkswagon's change through the gears too quickly, unless in sports mode. Perhaps this is to keep economy down.

Just wondering what every1's views were on BMW's choice to stick with the conventional Steptronic for so long? After all the DCT has been available on selected cars since the LCI model came out.

Hopefully when the F30's come out they will have the DCT's as Standard

Originally Posted by _Rubicon_

I have the DCT in my 09 335i and it's an awesome box. On e of the reasons I bought the car & it hasn't disappointed. Once driving a DCT-type box you will never buy a manual again!

While dual clutch gearboxes are definitely a nifty piece of technology, the fact is that they can never achieve the low speed smoothness and fuss free motoring that a traditional torque converter auto can.

If you try an automatic from a x35i BMW, you'd be hard pressed to distinguish whether it's an auto or a DCT. The slushbox in your 320d is geared towards smooth driving and economy and is a completely different ZF unit, so that's why it might feel a bit sluggish compared to the S-tronic.

Torque converter autos have become so good these days that BMW does not see the need to introduce DCT across the whole range. I don't see the need either. The ZF on bmroxm5's 135i is so good that it really doesn't need DCT. In sports mode, it locks up the torque converter past 2nd gear so it becomes a direct link between the engine and wheels, and gets rid of the 'slip' that you speak off. Gear changes give the same 'kick in the ass' feel that I experienced with dual clutch equipped VWs.

For shift times, the steptronic is 200ms consistent for any up gearchange. DSG/DCT are harder to determine, since their shift times are highly variable depending on whether the computer predicted the correct gear change and pre-loaded the gear. The fastest they can achieve is in the 50-80ms range for a pre-loaded gear, but that can go up to anywhere up to 500ms, slower than the steptronic. Of course in a straight line drag race, you'd really be smashing through the gears in a dual clutch system. Don't believe the 8ms figure VW quote, because that is completely ridiculous. That is the time taken for the synchros to move and does not take into account the clutching action.

As for downchanges, the step takes about 600ms due to the need to blip the throttle. The dual clutches take the same amount of time, since their setup offers no advantages due to the fact that they also have to wait for the throttle blip. HOWEVER, if you make an unexpected downchange (such as 6th to 2nd, which in dual clutches is on the same shaft) that can take up to 900ms, slower than a manual driver! On the topic of throttle blips, the steptronic does that extremely well and feels exactly the same as the DCT.

Combine this with the low speed shunting and jerkiness inherent to dual clutch systems that is non-existent in an auto, then BMW is doing it right for sticking with the torque converter. Just look at the issues VW owners have with their DSGs and you'll see why. This is not taking into account the maintenance cost for clutchpacks and the like, plus the low tolerance for increased power via mods. An auto is maintenance free and can usually take anything you throw at it with a simple ATF change.

The new 8speed ZF in the new range of BMWs are even better - shift times are apparently down to 100ms, which is pretty much on par with the best dual clutch systems. To put this into perspective, the DSG on the old Audi TT had a 200ms shift time.

[pcockley]

Well someone paid attention at school.

Thanks the the time and effort in puting that together, I found it interesting

[wassell2381]

Originally Posted by pcockley

Well someone paid attention at school.

Thanks the the time and effort in puting that together, I found it interesting

Sounds good man. There had to be some reason. DCT's are a complicated setup and perhaps there is going to be costly repair bills down the track.

Looking forward to driving the new F30 320d 8sp aye. The car's really grown on me. Everythins looks good except that fugly after though screen.

[RaihaX]

Originally Posted by Jeef Beef

While dual clutch gearboxes are definitely a nifty piece of technology, the fact is that they can never achieve the low speed smoothness and fuss free motoring that a traditional torque converter auto can.

If you try an automatic from a x35i BMW, you'd be hard pressed to distinguish whether it's an auto or a DCT. The slushbox in your 320d is geared towards smooth driving and economy and is a completely different ZF unit, so that's why it might feel a bit sluggish compared to the S-tronic.

Torque converter autos have become so good these days that BMW does not see the need to introduce DCT across the whole range. I don't see the need either. The ZF on bmroxm5's 135i is so good that it really doesn't need DCT. In sports mode, it locks up the torque converter past 2nd gear so it becomes a direct link between the engine and wheels, and gets rid of the 'slip' that you speak off. Gear changes give the same 'kick in the ass' feel that I experienced with dual clutch equipped VWs.

For shift times, the steptronic is 200ms consistent for any up gearchange. DSG/DCT are harder to determine, since their shift times are highly variable depending on whether the computer predicted the correct gear change and pre-loaded the gear. The fastest they can achieve is in the 50-80ms range for a pre-loaded gear, but that can go up to anywhere up to 500ms, slower than the steptronic. Of course in a straight line drag race, you'd really be smashing through the gears in a dual clutch system. Don't believe the 8ms figure VW quote, because that is completely ridiculous. That is the time taken for the synchros to move and does not take into account the clutching action.

As for downchanges, the step takes about 600ms due to the need to blip the throttle. The dual clutches take the same amount of time, since their setup offers no advantages due to the fact that they also have to wait for the throttle blip. HOWEVER, if you make an unexpected downchange (such as 6th to 2nd, which in dual clutches is on the same shaft) that can take up to 900ms, slower than a manual driver! On the topic of throttle blips, the steptronic does that extremely well and feels exactly the same as the DCT.

Combine this with the low speed shunting and jerkiness inherent to dual clutch systems that is non-existent in an auto, then BMW is doing it right for sticking with the torque converter. Just look at the issues VW owners have with their DSGs and you'll see why. This is not taking into account the maintenance cost for clutchpacks and the like, plus the low tolerance for increased power via mods. An auto is maintenance free and can usually take anything you throw at it with a simple ATF change.

The new 8speed ZF in the new range of BMWs are even better - shift times are apparently down to 100ms, which is pretty much on par with the best dual clutch systems. To put this into perspective, the DSG on the old Audi TT had a 200ms shift time.

to your wisdom old man

[John_01]

Jeef, Thanks for the informative post.

I am a fan of DCT. I think it would be better than a conventional auto if the car is going to be used for track days. Its about 10kg lighter than the ZF Auto, and I expect it wouldn't have issues with overheating in heavy use. Personally I like using a manual transmission on the roads, but I think I'd be better off with the DCT for track days.

For use in traffic I found the DCT in the 135i to be super smooth when I did a 20 min test drive at the dealer. Maybe there's something I don't know about, but I couldn't figure out why people criticise the DCT for jerkiness.

[Jeef Beef]

Originally Posted by wassell2381

Sounds good man. There had to be some reason. DCT's are a complicated setup and perhaps there is going to be costly repair bills down the track.

Looking forward to driving the new F30 320d 8sp aye. The car's really grown on me. Everythins looks good except that fugly after though screen.

DCTs are definitely more expensive in the long run due to more moving parts and higher complexity. The clutches also need to be replaced at certain intervals.

Originally Posted by RaihaX

to your wisdom old man

Damnit!

Originally Posted by John_01

Jeef, Thanks for the informative post.

I am a fan of DCT. I think it would be better than a conventional auto if the car is going to be used for track days. Its about 10kg lighter than the ZF Auto, and I expect it wouldn't have issues with overheating in heavy use. Personally I like using a manual transmission on the roads, but I think I'd be better off with the DCT for track days.

For use in traffic I found the DCT in the 135i to be super smooth when I did a 20 min test drive at the dealer. Maybe there's something I don't know about, but I couldn't figure out why people criticise the DCT for jerkiness.

I'm certainly a fan of the DCT in a track setting and using launch control in a straight line. However, dual clutch systems are the ones prone to overheating issues during track use which is a bit ironic considering that's where they excel. I'm sure the M-DCT in the M3 doesn't have that problem, but a mate's previous SST gearbox on his Evo completely fucked up after a few years of ownership.

Dual clutch systems in BMWs are good compared to the others I think because the computer tends to slip the clutch a bit more, but compared to an auto or a good manual driver, the difference is still obvious. Try reverse parking up a slope with a DSG car, I had quite a laugh watching my friend trying to do it in his DSG equipped Golf GTI. The fact is, the computer can only adjust clutch input reactively (and to a very limited extent proactively based on incline sensors) but a manual driver can adjust the clutch proactively based on current conditions and what he can see coming up.

An auto of course doesn't have that issue since it's always connected to the engine. Many these days don't seem to be aware that most 'sporty' autos lock up the torque converter to prevent 'slip' and power loss after changing from 1st to 2nd in sport mode. It makes them feel like automated manuals as they slam thru the gears. Out of sport mode in drive, the torque converter lockup only happens during cruising to save fuel and 'slurs' the gearchanges to give that unmatched creaminess.

[athlon70]

Originally Posted by _Rubicon_

I have the DCT in my 09 335i and it's an awesome box. On e of the reasons I bought the car & it hasn't disappointed. Once driving a DCT-type box you will never buy a manual again!

I said the same when i got my wife a Gti.

Best thing invented since sliced bread.

[athlon70]

Originally Posted by Jeef Beef

Try reverse parking up a slope with a DSG car, I had quite a laugh watching my friend trying to do it in his DSG equipped Golf GTI.

Your mate can't drive them properly, My wife does it it blindfolded better then 99% of people could in a manual.

PS: The SST in the EVO is an embarrassment for the Dual Clutch crowd.

[Jeef Beef]

Originally Posted by athlon70

Your mate can't drive them properly, My wife does it it blindfolded better then 99% of people could in a manual.

PS: The SST in the EVO is an embarrassment for the Dual Clutch crowd.

There's nothing to know for a DSG, you move your foot off the brake and onto the accelerator. The split second delay before the clutch fully engages is simply horrendous on a serious slope. Those manual drivers don't know what they are doing if they are not friction pointing the clutch before releasing the brake. Even left foot braking his car didn't work, the clutch simply to take its time engaging.

In terms of smoothness, it can't compare to a simple torque converter auto. Let's not discuss maintenance

[KF]

Hi All

We drive a 7 speed Skoda Fabia. Yes a whole 77Kw. It is a mighty little car, much nicer to drive than Mazda 3, Corolla etc. It goes very well once it is doing five KPH. Just don't park where you have to reverse to get out!!

Ease the excellarator off and the clutch disengages, touch the brake and the clutch disengages.

If we have to park on a slope we just face up hill or find another park!

KF

[John_01]

Isn't it possible to use the hand brake for hill starts?

[davidturnedge]

I think traditional automatic suppliers (ZF for example) saw the light years ago when automatic clutch manual tech was reaching reliability levels approaching mass sale... the last 5 years has seen dramatic improvement in traditional auto tech (200ms shift time for the new ZF 8 speeder for example)... makes me wonder if I'd ever take the risk of the extra tech in an automatic clutch box as a daily driver.

Sydney Harbour Bridge tow truck drivers have mentioned to me in the past that they rank VW DSGs as one of the most unreliable cars they get to tow.

I can't wait to try the new F30 auto box... I just didn't see improvement from the E46 5AT to the E90 6AT but I am expecting to be blown away by the F30 8AT.

[KF]

Hi All

We have the seven speed DSG in the Skoda, other than trying to reverse out of a up hill car park, we though that the DSG performed better than out current six speed ZF. We had driven the ZF transmission car for over 12,000km before driving it down a hill.

Yes we live on the largest piece of flat land in the world.

The ZF will change down al by itself on a down hill road to maintain the cruise control speed, The Skoda requires the brakes to be used in a down hill section to maintain speed. The DSG enables VW's and Skoda's to out perform there competitors, our 77Kw Skoda is quicker than 100kw Mazda's and Corolla's!.

Someone suggested that you can use the hand brake to restrict your speed when reversing up a hill. I asked the service manager how you got on backing a $250,000 A8, and he suggested using the hand brake. This is only in the sort of tight maneuvours that you would have to slip the clutch in a manual. A torque converter trany would have no trouble.

The six speed VW DSG had "issues", the same guys advised that they had 7 speed DSG's with over 200,000km with no problems.

We look forward to next weeks arrival of the X3 3.0D to find out if we think that the 8 speed ZF is better than the 7 speed DSG.