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      01-25-2010, 12:57 AM   #1
swamp2
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A couple of interesting DCT tidbits from MT

From the most recent issue.

1. According to Viper engineers a DCT would be good for at least a 3 second improvement in its Nurburgring time. I would bet that is actually found from testing not purely guess work. However, it does raise the very relevant question, what is the real source of the gain, faster shifts, more gears, better ratios or all three? Either way this probably makes for a reasonable estimate for what we should expect from the M-DCT (if we ever get any bloody Sportauto time for the car...). Link to a link of the article here.

2. A nice discussion of many points that have turned into fierce debates here in the forum on the topic of MT vs DCT. Note: If it is good enough to be the only transmission choice on the new Ferrari 458, it is probably good enough for any of us and the M3. Of course the article does discuss the role of personal preference as well. It does conclude firmly on the pro DCT side offering the obvious choice for a real "go fast" - use your newly freed up left foot for braking! Link.
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      01-25-2010, 03:07 AM   #2
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Quote:
Originally Posted by swamp2 View Post
From the most recent issue.

1. According to Viper engineers a DCT would be good for at least a 3 second improvement in its Nurburgring time. I would bet that is actually found from testing not purely guess work. However, it does raise the very relevant question, what is the real source of the gain, faster shifts, more gears, better ratios or all three? Either way this probably makes for a reasonable estimate for what we should expect from the M-DCT (if we ever get any bloody Sportauto time for the car...). Link to a link of the article here.

2. A nice discussion of many points that have turned into fierce debates here in the forum on the topic of MT vs DCT. Note: If it is good enough to be the only transmission choice on the new Ferrari 458, it is probably good enough for any of us and the M3. Of course the article does discuss the role of personal preference as well. It does conclude firmly on the pro DCT side offering the obvious choice for a real "go fast" - use your newly freed up left foot for braking! Link.
As I see it, the majority of that advantage comes from the following:

a) The precise lightening quick 10-30 millisecond 1st thru 7th gear shifts that only DCT can deliver on a consistent basis. (no human driver can match that)

b) The combination of the DCT's transmission gear ratio combined with the differential gear ratio. (final drive)

c) The fact that the next gear change is always "pre-selected" by the DCT's control module based on the acceleration (and mode) your DCT tranny is in at the time. (the next gear is ready and waiting to be engaged on a separate clutch shaft)

d) Perfect rev-matching downshifts improves the efficiency of the gear changes and maximizes your performance. (lowering the overall lap time)

e) With DCT, there is no hydraulic 'fork' to engage or disengage in order to change gears. (upshifting or downshifting) This was the reason so many people disliked the clumsy way the SMG tranny functioned. (under heavy acceleration, the clutch engagement was very abrupt)

The DCT transmission in our cars allows all the engine power to be applied gradually (perfectly modulating the clutch engagement via electro-hydraulic closed loop system) when a vehicle is moving. This is all monitored and controlled by a computer algorithm that can repeat perfect shifts all day long. (no human driver can do that either) The DCT transmission will only briefly interrupt the flow of power for a few milliseconds to perform these gear changes. (well...since the latest DCT update! lol...) The DCT transmission engages the clutch in the most efficient manner possible, and this allows more of the engines power to transfer to drive wheels with minimal delay or loss.

Bottom Line: The DCT transmission can almost instantly engage and disengage the clutch to start/stop the transfer of power from the engine to the drive shaft. (which will beat the overall efficiency of a traditional 6-speed manual transmission and human driver engaging and disengaging a mechanical 3rd pedal clutch during a race)

What is your theory Swamp?
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      01-25-2010, 03:27 AM   #3
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honestly I think it just comes down to preference.

pure performance I think the DCT is faster.

but for pure enjoyment I think the 6mt is more fun the drive.

but that is just me!
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      01-25-2010, 07:10 AM   #4
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As far as transmissions are concerned, DCT, SSG, DSG or whatever you want to call it are the next best thing since sliced bread. Yes, for all the reasons mentioned above. But there's one caveat, in particular towards those who want to go all out modding.

Granted, these are designed with the particular vehicle they will be installed in mind. The question then becomes how much power can they hold. If the DCT model that I'm looking at is right, then it can hold 442 lb/ft (Getrag 7DCI600). Granted, that's a lot, but at what point will it not be? After some time, in partucular after a SC is slapped on these motors, the clutches will weaken. It would just be a matter of the aftermarket coming out with a clutch kit for these things, which, obviously, will be pretty expensive.

A friend of mine believes that within 10 years, these will be the only options availble on any car. I still think that some will offer a MT, but unfortunately those days are numbered. I for one am definitely a fan of the DCT or any dual clutch for that matter. But I have to second Eugune...there's something to be said about driver involvement. Being connected to any car like that is definitely a more enjoyable experience.
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      01-25-2010, 10:33 AM   #5
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Its good for a 3 sec improvement on the Ring when driven by a professional. I would guess it is good for much more than that for the average novice driver.
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      01-25-2010, 11:07 AM   #6
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It's good for a 3 second advantage when it works. According to car and driver, the DCT HURT their lap times because it wouldn't down shift when asked too. MT FTW!
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      01-25-2010, 02:27 PM   #7
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Can you say software update?

Quote:
Originally Posted by ChitownM3 View Post
It's good for a 3 second advantage when it works. According to car and driver, the DCT HURT their lap times because it wouldn't down shift when asked too. MT FTW!
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      01-25-2010, 02:39 PM   #8
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I had a chance to drive my best friends M3 DCT more than enough times to get to know the car and the transmission fairly well. And I now own an MT M3. The DCT will always be quicker regardless of the circumstances. However, unless you're on the track CONSTANTLY, it becomes a bit dull after some time and takes a way a lot of the fun from the M3. No matter how you drive it, DCT will never be as involving as an MT. This is just my opinion of course.
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      01-25-2010, 04:24 PM   #9
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Quote:
Originally Posted by powertrip View Post
Can you say software update?
They claimed they had updated the software. As I have said before in any DCT vs 6MT thread. No 6MT owner can debate the fact that we can't shift as fast as a DCT. I won't even debate that a DCT isn't faster around a racetrack. The thing we debate is driver involvement in driving the car and the enjoyment we get from shifting our own gears and attempting our own rev matched downshifts.
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      01-25-2010, 11:50 PM   #10
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Quote:
Originally Posted by King Tut View Post
They claimed they had updated the software. As I have said before in any DCT vs 6MT thread. No 6MT owner can debate the fact that we can't shift as fast as a DCT. I won't even debate that a DCT isn't faster around a racetrack. The thing we debate is driver involvement in driving the car and the enjoyment we get from shifting our own gears and attempting our own rev matched downshifts.
I don't know about that. I'd still like to see what an MT car would have gotten at the C&D Lightning lap.
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      01-26-2010, 01:02 AM   #11
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Quote:
Originally Posted by King Tut View Post
They claimed they had updated the software. As I have said before in any DCT vs 6MT thread. No 6MT owner can debate the fact that we can't shift as fast as a DCT. I won't even debate that a DCT isn't faster around a racetrack. The thing we debate is driver involvement in driving the car and the enjoyment we get from shifting our own gears and attempting our own rev matched downshifts.
enjoy driving is it.... I totally agree with what your saying.
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      01-26-2010, 01:54 AM   #12
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Quote:
Originally Posted by King Tut View Post
They claimed they had updated the software. As I have said before in any DCT vs 6MT thread. No 6MT owner can debate the fact that we can't shift as fast as a DCT. I won't even debate that a DCT isn't faster around a racetrack. The thing we debate is driver involvement in driving the car and the enjoyment we get from shifting our own gears and attempting our own rev matched downshifts.


That's the only part of a manual I miss. Getting the rev matched perfectly on a downshift is a SWEET feeling.



Lemans, I take you have a DCT???
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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      01-26-2010, 07:39 AM   #13
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Quote:
Originally Posted by aus View Post
[/b]

That's the only part of a manual I miss. Getting the rev matched perfectly on a downshift is a SWEET feeling.



Lemans, I take you have a DCT???

I really liked the auto-clutch manual in the E46 M3...but I love the dual-clutch transmission in the E92 M3.

Especially since the latest software fix!
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      01-26-2010, 02:31 PM   #14
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Quote:
Originally Posted by Lemans_Blue_M View Post
I really liked the auto-clutch manual in the E46 M3...but I love the dual-clutch transmission in the E92 M3.

Especially since the latest software fix!
I agree completely, but for some reason, in Road and Track, they keep mentioning the delay at slow speeds with their Long Term M3. I wonder if they did the software? It should have been done at the 1200 mile or 15000 mile oil change at least.
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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      01-26-2010, 11:13 PM   #15
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Quote:
Originally Posted by Lemans_Blue_M View Post
I really liked the auto-clutch manual in the E46 M3...but I love the dual-clutch transmission in the E92 M3.

Especially since the latest software fix!
when was the latest ome released time frame wise?
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