Crown
Board: Porsche
Language: English
Region: Worldwide
Close
CloseForum - Thread
Re: DSG gearbox
Quote:
mav21386 said:
does anyone know if and when porsche is going to introduce the DSG gearbox on the 911 and the boxster?
First rumour indicated DSG for the first time in the GT3.
Second rumour indicated DSG for the first time in the Cayman S too boost initial sales.
Third rumour (the latest one) indicated DSG for the first time in the 997 Turbo.
On a long term run, I think that DSG will replace the Tiptronic, especially since the Tiptronic is from Daimlerchrylser and the DSG is originating from VW.
Re: DSG gearbox
Quote:
Mithras said:
DSG actually originates from Porsche. The VW/Audi unit is I believe based on the 962 double clutch setup...
DSG has been used for the first time in a Volkswagen, they also have the patent rights for DSG. The Volkswagen Golf, the Audi TT and even the VW Touran (a soccer mom minivan) and other models are available with DSG.
I'm pretty sure that when Porsche introduces DSG, it will be slightly different and have a different name of course.
Oh, did you know that the Bugatti Veyron is supposed to get a shifting system based on DSG? Now who's the owner of Bugatti? Right.
The PDK Porsche system you're probably referring to may be viewed as the grandfather of DSG but it doesn't have much in common, especially since DSG is full of electronics and control units.
Apr 18, 2005 8:28:01 AM
- Kimi
- Co-Pilot
-
- Loc:
- Posts: 192, Gallery
- Registered on: Dec 18, 2003
- Reply to: palenimbus
Re: DSG gearbox
Quote:
Danny G said:
Can anyone explain for the ignorant (me) what the difference is?
Here's something to start with:
http://www.autozine.org/technical_school/gearbox/tech_gear_manual.htm#Twin-clutch
Re: DSG gearbox
This article highlights the strengths of the DSG (upshifting 10 times faster than SMG II), and the weaknesses (extremely slow downshifting because it doesn't match the throttle blip). The question I have about it is, if the driver matches the revs (i.e. toe heeling), does the downshifting problem vanish? If so, I'd love to have a DSG. If not, then it's a bit mediocre...
Re: DSG gearbox
Quote:
Hurst said:
... and the weaknesses (extremely slow downshifting because it doesn't match the throttle blip). ... then it's a bit mediocre...
I think you misjudge when you characterize a 600 millisecond downshift that includes a throttle blip as "extremely slow".
From your comment, one might get the impression you think you would be faster if you were allowed to intervene in place of the DSG computer. Would you like to make a little wager on it?
Besides, fast shifting is only critical for not interrupting power flow while accelerating.
The brakes are for decelerating.
Apr 24, 2005 10:08:42 PM
-
Carlos from Spain
- Rennteam Moderator
-
- Loc: Spain. , Spain
- Posts: 21152, Gallery
- Registered on: Feb 9, 2003
- Reply to: W8MM
Re: DSG gearbox
I agree, even its longest downshift is 900ms but when going from 6th to 2nd gear! thats slow?
If you are coming down a straight after flooring it in 6th gear and you want to make a 2nd gear corner, by the time you finish scrubbing off all that speed (maybe a 90mph speed diferential) with the brakes and allowing enough match rev so as not to lock the rears, the DSG in 900ms would long done before that.
Not mention that you will even have time to even drop the gears sequentally one by one with their individual rev match blip from 6th to 2nd instead of jumping 4 gears in one time.
The important part if upshifting speed and least power interuption IMO.
If you are coming down a straight after flooring it in 6th gear and you want to make a 2nd gear corner, by the time you finish scrubbing off all that speed (maybe a 90mph speed diferential) with the brakes and allowing enough match rev so as not to lock the rears, the DSG in 900ms would long done before that.
Not mention that you will even have time to even drop the gears sequentally one by one with their individual rev match blip from 6th to 2nd instead of jumping 4 gears in one time.
The important part if upshifting speed and least power interuption IMO.
Apr 25, 2005 2:49:05 PM
- Hurst
- Veteran
-
- Loc: Potomac, MD
- Posts: 1255, Gallery
- Registered on: Apr 15, 2005
-
Reply to:
Carlos from Spain
Re: DSG gearbox
Okay. First of all, all these situations are race oriented, because for simple driving, the downshifting gap is irrelevant. But for the sake of race:
Let's say you're flying down a straightaway, into 5th or 6th gear (in excess of 110mph), when there is an upcomming hard right turn, where you'll have to downshift to at least 2nd gear and take the turn at tops 40mph. Is there a 900ms shift differential from 6th-2nd, or is that the differential between each gear from 6th to 2nd (6-5, 5-4, 4-3, 3-2)? If it is for all the shifts, how is the transition broken down?
Let's say you're flying down a straightaway, into 5th or 6th gear (in excess of 110mph), when there is an upcomming hard right turn, where you'll have to downshift to at least 2nd gear and take the turn at tops 40mph. Is there a 900ms shift differential from 6th-2nd, or is that the differential between each gear from 6th to 2nd (6-5, 5-4, 4-3, 3-2)? If it is for all the shifts, how is the transition broken down?
Re: DSG gearbox
Hurst,
Slowing down takes longer than you think.
Let's say we're decelerating at 1.5 g (if we can).
1.5 g = (1.50)(32 ft/sec/sec) = 48 ft/sec/sec = 33 MPH/sec
OK, at 1.5 g, how much do we slow down in the time it takes the DSG to shift down from 6th to 2nd gear?
(0.9 sec)(33 MPH/sec) = 29 MPH
If mid band power in 2nd gear is 50 MPH, then you won't have any trouble tracking your DSG car if you don't go any slower than 79 MPH in 6th gear.
Can your future car manage to top 80 MPH in 6th at the track?
If so, DSG will not hamper your style.
If you can't get up to 80 MPH in 6th, then it might be a problem.
Slowing down takes longer than you think.
Let's say we're decelerating at 1.5 g (if we can).
1.5 g = (1.50)(32 ft/sec/sec) = 48 ft/sec/sec = 33 MPH/sec
OK, at 1.5 g, how much do we slow down in the time it takes the DSG to shift down from 6th to 2nd gear?
(0.9 sec)(33 MPH/sec) = 29 MPH
If mid band power in 2nd gear is 50 MPH, then you won't have any trouble tracking your DSG car if you don't go any slower than 79 MPH in 6th gear.
Can your future car manage to top 80 MPH in 6th at the track?
If so, DSG will not hamper your style.
If you can't get up to 80 MPH in 6th, then it might be a problem.
Apr 25, 2005 7:21:03 PM
-
Carlos from Spain
- Rennteam Moderator
-
- Loc: Spain. , Spain
- Posts: 21152, Gallery
- Registered on: Feb 9, 2003
- Reply to: Hurst
Re: DSG gearbox
Quote:
Hurst said:
Okay. First of all, all these situations are race oriented, because for simple driving, the downshifting gap is irrelevant. But for the sake of race:
Let's say you're flying down a straightaway, into 5th or 6th gear (in excess of 110mph), when there is an upcomming hard right turn, where you'll have to downshift to at least 2nd gear and take the turn at tops 40mph. Is there a 900ms shift differential from 6th-2nd, or is that the differential between each gear from 6th to 2nd (6-5, 5-4, 4-3, 3-2)? If it is for all the shifts, how is the transition broken down?
900ms would be for the entire 6th to 2nd downshift maneuver, the rerason why its the longest downshift is because since the 1-2-3 gears are in one bank and the 2-4-6 gears are in the other, in order to download from the highest gear (6th) to the lowest gear in the same bank (2nd) furthest away, it needs to first it downshift from 6th to 5th (to be able to load or enage the 2nd which was occupied by 6th) and then once 2nd is engaged it goes from the 5th to 2nd.
But as Mike says, scrubbing off the speed will take longer than the downshift shift. Test yourself with a manual and see how long it will take you with a manual to drop say, two gears, with heel-to-toe rev matching and full braking into the corner after coming at WOT into the turn. With the speed gaps between gears of cars the HP outputs such as Porsche, the difference in speed is significant.
On the upshift hownever, its as fast as you can shift what matters, and the DSG version of the Audi/VW is already a wooping 10 times faster than the fastest sequential available today, BMW's SMG, not to mention Ferraris' F1 which is even twice as slower than the BMW's. Practically no power interruption allowing for even slight faster acceleration times than the manual counterpart.
Apr 27, 2005 12:33:59 PM
- CarreraGtRacer
- Veteran
-
- Loc: Houston, TX
- Posts: 1181, Gallery
- Registered on: Jan 1, 2004
-
Reply to:
Carlos from Spain
Apr 27, 2005 1:05:48 PM
-
Carlos from Spain
- Rennteam Moderator
-
- Loc: Spain. , Spain
- Posts: 21152, Gallery
- Registered on: Feb 9, 2003
- Reply to: CarreraGtRacer
Re: DSG gearbox
Quote:
W8MM said:
Hurst,
Slowing down takes longer than you think.
Let's say we're decelerating at 1.5 g (if we can).
1.5 g = (1.50)(32 ft/sec/sec) = 48 ft/sec/sec = 33 MPH/sec
OK, at 1.5 g, how much do we slow down in the time it takes the DSG to shift down from 6th to 2nd gear?
(0.9 sec)(33 MPH/sec) = 29 MPH
If mid band power in 2nd gear is 50 MPH, then you won't have any trouble tracking your DSG car if you don't go any slower than 79 MPH in 6th gear.
Can your future car manage to top 80 MPH in 6th at the track?
If so, DSG will not hamper your style.
If you can't get up to 80 MPH in 6th, then it might be a problem.
Thanks, this helps clarify things. And as a matter of fact, I think my car can top 80mph in 6th!
Re: DSG gearbox
Quote:
Hurst said:
btw, I hear that the new A3 in North America has a DSG. Has anyone tried it? Is it nice? If so, I'm gonna go to my local Porsche/Audi dealer and test it out
Yep, the new A3 has a DSG, as the new golf 5 too. You can try the GTI with a DSG.
Did not try it myself though.
Forum
About Rennteam | Help | Terms of use | Privacy Policy | Support | Contact | Imprint | Archive
Powered by
Community
and
