Direct Shift Gearbox

[mazdamazda]

I just read James Deakin's article on the DSG equipped A3 turbo last week. The A3 turbo is rated at 140hp and when Autoplus dynoed it, it showed 140hp at the wheels!

Is this the holy grail of transmissions or what? To boot, shifting takes only about 8ms, even faster than a Ferraris!

From wikipedia

Advantages

* Extreme fast up shift and downshift time of 8 milliseconds
* Practically no power loss whatsoever, because of the short shift time
* Better fuel economy than the planetary geared automatic transmission and manual transmission
* When the car is going downhill the clutch disengages, allowing the car to coast

Disadvantages

* Response time from letting off the throttle and then reapplying is lengthy, around 400ms, depending on the situation
* Can be expensive to manufacture, this discourages many automakers
* They are heavy: 75kg vs. 47.5 for comparable Getrag DSG and Manual models
* Being complex mechanisms there is more to potentially break

[Blackraven]

DSG ba is classified under the "slushbox" category?

If so, then:

"Slushbox":
conventional AT, CVT, SMG, DSG, sequential transmissions, etc.
Basically any electronic transmission that has a standard auto mode and at times a manual mode option (a.k.a. the "+" and "-"). Some cars can "LOCK" the shifter in place at the stationary gear when the ignition is off and release it when it is on. There electronics that are tied in with these "slushboxes".

"Stick"
You must control the gears by yourself. Gears range from 1st to 5th (some have 6th) and a reverse gear R. No electronics to help you hear as you do everything by yourself.

Are these correct definitions (incl. the category ng DSG)???

Thanks

[niky]

Holy cow... that's not bad... especially considering it's a turbo car, and turbo cars usually lose lots of power in our local weather... of course, Audi might have underquoted it a bit.

How much does the turbo model cost?

[niky]

DSG ba is classified under the "slushbox" category?

If so, then:

"Slushbox":
conventional AT, CVT, SMG, DSG, sequential transmissions, etc.
Basically any electronic transmission that has a standard auto mode and at times a manual mode option (a.k.a. the "+" and "-"). Some cars can "LOCK" the shifter in place at the stationary gear when the ignition is off and release it when it is on. There electronics that are tied in with these "slushboxes".

"Stick"
You must control the gears by yourself. Gears range from 1st to 5th (some have 6th) and a reverse gear R. No electronics to help you hear as you do everything by yourself.

Are these correct definitions (incl. the category ng DSG)???

Thanks

I don't think so.

Slushbox refers to the fluid used to run a conventional automatic. Conventional autos use a torque converter that has fan blades. As it turns, it pushes the fluid around, which turns the output shaft... it's only after a certain amount of rpms that the input and output shafts are locked to each other.

CVTs, SMGs and DSGs use a different system.

SMGs and DSGs are considered as "robotized" manuals, because they still use clutches.

CVTs are something else, entirely... belt-driven for the most part, but there are some fully-mechanical CVTs.

[cocoy]

Holy cow... that's not bad... especially considering it's a turbo car, and turbo cars usually lose lots of power in our local weather... of course, Audi might have underquoted it a bit.

How much does the turbo model cost?

just curious how turbo cars will lose lots of power in our weather?

[Blackraven]

I don't think so.

Slushbox refers to the fluid used to run a conventional automatic. Conventional autos use a torque converter that has fan blades. As it turns, it pushes the fluid around, which turns the output shaft... it's only after a certain amount of rpms that the input and output shafts are locked to each other.

CVTs, SMGs and DSGs use a different system.

SMGs and DSGs are considered as "robotized" manuals, because they still use clutches.

CVTs are something else, entirely... belt-driven for the most part, but there are some fully-mechanical CVTs.

Waaaah, this is getting complicated.

Hmm....
Would it be good if we use the "layman's definition" of the "slushbox" as:
-a type of transmission that has a an AUTO mode/"D" mode (computer/electronics will do gear shifting for you)
-any transmission that has "P-R-N-D"
-always has a stationary gear "N" (with "P" on majority of vehicles)
-optional manual mode/manual overdrive (as denoted by "+" and "-" modes)
-can be locked in-place when placed at stationary gear (either "N" or "P") when ignition is off.
-it is tied to computer/electronics of a vehicle (ie. gear indicator is displayed in dashboard)

"STICK"
-user/driver places the shifter in one of the designated positions which represent the gears ranging from 1-5 (with a 6th on some cars) plus a reverse gear
-user must step on clutch pedal before "placing" the shifter in a corresponding position or gear
-there are no computer/electronics tied to it (thus you can see a gear indicator noting which gear you are in)
-since there are no computer/electronics connected to the "stick", the gear changing must be done by the user/driver (there is no other way hence it's a "manual")

Hmm....so based on the layman's defintion wouldn't the DSG qualify under the "slushbox" category since it has P-R-N-D and has "+"/"-" (which satisfies at least one of the conditions)???

Can the same thing be said with VAG group's Multitronic CVT 7-speed (uses the same PRND & +/- features)???

[mikmik316]

DSG was demo'ed in Top Gear before with the Golf GTi I think, and the blokes were really amazed by the thing... like what Di Caprio said in the Aviator... "it's the wave of the future"

[niky]

Waaaah, this is getting complicated.

Hmm....
Would it be good if we use the "layman's definition" of the "slushbox" as:
-a type of transmission that has a an AUTO mode/"D" mode (computer/electronics will do gear shifting for you)
-any transmission that has "P-R-N-D"
-always has a stationary gear "N" (with "P" on majority of vehicles)
-optional manual mode/manual overdrive (as denoted by "+" and "-" modes)
-can be locked in-place when placed at stationary gear (either "N" or "P") when ignition is off.
-it is tied to computer/electronics of a vehicle (ie. gear indicator is displayed in dashboard)

"STICK"
-user/driver places the shifter in one of the designated positions which represent the gears ranging from 1-5 (with a 6th on some cars) plus a reverse gear
-user must step on clutch pedal before "placing" the shifter in a corresponding position or gear
-there are no computer/electronics tied to it (thus you can see a gear indicator noting which gear you are in)
-since there are no computer/electronics connected to the "stick", the gear changing must be done by the user/driver (there is no other way hence it's a "manual")

Hmm....so based on the layman's defintion wouldn't the DSG qualify under the "slushbox" category since it has P-R-N-D and has "+"/"-" (which satisfies at least one of the conditions)???

Can the same thing be said with VAG group's Multitronic CVT 7-speed (uses the same PRND & +/- features)???

THe problem with the term "slushbox" is that it specifically refers to the fact that the conventional automatic is filled with fluid and shifts in an... errh... slushy manner.

When arguing the merits of transmission types, it pays to be specific... different kinds of "automatics" and "manuals" have their own advantages and disadvantages.

For example, I'd heartily recommend a conventional automatic for a big V8 engined car, but not a compact. I'd recommend a CVT for a compact, but not for a truck or sportscar. I'd recommend a "roboticized" manual (SMG/DSG) for a sports car, but I wouldn't recommend either for an economy commuter (too much shift-shock in SMG, DSG too expensive).

It's complicated, yes, but simplifying it by lumping them all together suggests certain systems have traits that they don't really have.

--------------

RE: turbos and power loss:

It's all about the heat. I've driven the Hyundai Accent on two different occassions, and it feels noticeably more sluggish in the summer. The Ford Focus ST was dyno-tested here to deliver less power than was expected, and acceleration testing numbers are somewhat disappointing. On bigger diesel trucks with large intercoolers and huge gaping grilles, it's less of a problem, but compacts really suffer... I've even seen a 1.8T Audi TT here once sitting in a cloud of steam (old TT, some five to ten years ago).

[Blackraven]

When arguing the merits of transmission types, it pays to be specific... different kinds of "automatics" and "manuals" have their own advantages and disadvantages.

For example, I'd heartily recommend a conventional automatic for a big V8 engined car, but not a compact. I'd recommend a CVT for a compact, but not for a truck or sportscar. I'd recommend a "roboticized" manual (SMG/DSG) for a sports car, but I wouldn't recommend either for an economy commuter (too much shift-shock in SMG, DSG too expensive).

It's complicated, yes, but simplifying it by lumping them all together suggests certain systems have traits that they don't really have.

I'm still confused

Alright then, scratch the terms "slushbox" and "stick". Okay.
But... for the point of simplicity:
Would it be better to just classify them into two main/general categories:
"Automatic" and "Manual"???

So in this case, the DSG and SMG would be placed in the "Automatic" category because of it having a standard auto mode feature. Same thing with the CVT up to the conventional AT. Ie. There is the presence of a D (drive mode)/Auto mode.

To put this in application, let's use the noob driver's example.

Noob driver is about to practice for his upcoming driver's license exam. He has little-to-no knowledge of automobiles and the operation and that's why he's learning now. Problem is, after months of training, he still has no capability of operating a vehicle with a manual transmission. He only knows how to operate "automatic" transmission.

Come to the day of the driving test, he prayed that his test car would be an automatic. Surprisingly, he got a BMW M6 as his driving test car.

To his surprise, he was fazed by the transmission layout as all he could see were the ff: +,-, R, stationary gear ("N" ata). He panicked knowing that he can't operate a tranny other than an auto...........until he sees this D/S mode.

He then checks the vehicle manual and discovers that when in D/S mode, the computer/electronics will do the shifting & forward acceleration responsibilities for the driver. In short, the car does have an auto mode.

Noob driver: Oh goodness, this car is an "automatic" after all. Praise be Jesus

An hour after the driving test finished, the results came in. He passed all of the requirements and he has been granted a driver's license.

Noob Driver: If it weren't for the car being an "automatic", I would have had to take the test all over again.

Case in point.

[Dr.Kamiya]

Given that criteria, DSG would fall under "automatic", but certainly not under "slushbox".

The amazing thing about DSG is how the tranny uses two clutches. One for the odd numbered gears, another for the even ones. Even while you're in a gear, the other clutch preselects the next gear for you, so when it comes time to upshift the change is almost instantaneous.

Best Motoring International has a video comparing the Golf GTI in DSG with its manual brother. Amazingly, despite a 50kg weight handicap, and a pro race driver shifting for the manual, the DSG pulls away with every gearchange.

[mazdamazda]

I'm still confused

Alright then, scratch the terms "slushbox" and "stick". Okay.
But... for the point of simplicity:
Would it be better to just classify them into two main/general categories:
"Automatic" and "Manual"???

Err, it is not "better" just clasify them into automatic or manual, since an "automatic" tranmission can have a manual mode & a "manual" transmission can have an automatic mode.

For a "simplified" classification, it can be stick or non-stick.

[Blackraven]

For a "simplified" classification, it can be stick or non-stick.

Good point.

Pero I remember a quote from a VAG executive (sa EVO UK magazine) that they are aiming to equip more than 50% of their automatic tranny models with the DSG auto transmission for 2008 model year.

So would it be good then to put the DSG under the "non-stick" category? DSG uses "P-R-N-D" layout right (the + and - comes as an additional feature)??? To the eyes of the average non-informed driver, the first he/she will notice is that it looks like an automatic (ie. having PRND)

Waaaah, naku this debate could go on endlessly

[niky]

Let's just say it's "clutched" and "clutchless". And then modify that by saying "manual clutched" and "automatic clutched".

Many of the DSG and SMG's advantages over other automatics comes from having clutches instead of torque converters. I can just imagine that poor student, trying to smoothly park an M6 with SMG... shift... eeeek!... BRAKE! Oops! Sorry! The SMG is a total beast at low speeds... it doesn't slur the clutch in first gear like a full-manual driver can, and doesn't build speed gradually like a slushbox. The new DSGs are reputed to be almost as smooth as traditional ATs, though.

Yes, the debate could go on endlessly... on some other boards I go to, it erupts into flame wars every time someone mentions the word "automatic". :hihihi:

That's why it pays to be VERY specific. If you ask me if it's a good idea to buy a 1.3 liter AT for fuel economy in city driving, I'd tell you absolutely not. But if you were to say: "What about a 1.3 Honda City CVT?"... well, I'd say definitely.