Shaka

There are some dumb guys on this forum but you are the dumbest.

JoesC5

The DCT has only one input shaft to the two clutches. One of the two clutches is internal to the other. Then each clutch has it's separate shaft to it's respective part of the transmission.

Oh, and btw, while Acura has a 9 speed DCT in their NSX, their TLX has an 8 speed DCT with a torque convertor. GM also has a patent on a DCT with a torque convertor.

It is possible to get the best of both worlds. Smooth engagement from a stop, and at low crawling speeds, and ultra quick shifts, up and down when going through the gears, by combining a torque convertor with a DCT..

Shaka

Second dumbest.

SSsedanM6

He's actually right.
No one is going to put a single automated clutch in a mass produced car.
SMGs are absolutely terrible.
Lamborghini is regularly trashed for their garbage SMG in their top tier cars.


Your post says a lot about you and your intelligence.

JoesC5

Here is a Porsche DCT(PDK).

How many input shafts do you see?

If you are capable of understanding what you are seeing, you will also see that the two clutches are in one unit, and one clutch is internal to the other.




Here is the Tremec DCT.

Same questions as before.

rgregory

I have a Gallardo yes e-gear isn’t perfect but that has absolutely nothing to do with it being 1 or 2 clutches! It is about software and refinement.

The Lambo Aventador has a single clutch transmission that shifts in 50ms. 1 clutch is lighter and less rotating mass.

rgregory

Do some research on DCT. It is one shaft plane with 2 shafts. One is inside one is outside.

rgregory

See image:

JoesC5

What I posted is 100% accurate. The is only ONE input shaft to the two clutches and there are two output shafts from the two clutches to the transmission. Just because one output shaft is inside the other, makes no difference. It's still two independent output shafts being fed by two clutches that are fed by one input shaft that is fed by one crankshaft in the engine. Your shafts identified as shaft #1 and shaft #2 are the output shafts from the two clutches to the transmission gearing. Why don't you show the SINGLE input shaft with a number?

Or do you believe that every manufacturer that uses a DCT has two crankshafts in the engine to feed two input shafts to the two clutches?

rgregory

The shaft to the clutches isn't an input shaft to the transmission. The shafts from the clutches are then input shafts to the transmission that is what I am speaking of.

JoesC5

This is what I said in post #87.

"The DCT has only one input shaft to the two clutches. One of the two clutches is internal to the other. Then each clutch has it's separate shaft to it's respective part of the transmission."

100% accurate, so why are you arguing?

The dumbest post was Shaka's which I was arguing with.

Since the two clutches are an integral part of the DCT transmission, unlike the conventional manual transmission, there is only one input shaft to the DCT transmission.

lostsoul

there is only one shaft

SSsedanM6

Yup.
And, both transmissions are widely considered to be garbage. .

And, yes, it has everything to do with the fact that it's a single compared to dual clutches.
The poor programming only makes the bad situation worse.


The dual clutch transmission in the Huracan is a huge improvement over the old Lamborghini SMGs.

vetteman41960

I have owned a Lamborghini Gallardo and the egear is absolutely a terrible transmission. In auto mode shift a clunky and make for a horrible driving experience.

In manual mode shift up and down are fairly quick but also abrupt and jarring. There is also a terrible annoying delay from dead stop that require a small roll out before you can accelerate normally.

I now own a 458 Italia with DCT by Getrag. The car drives ever bit a smooth and comfortable in auto mode as my 2016 Callaway SC757. Absolutely no delay from a dead stop like the Lambo. and the up and down shift in manual mode are lighting quick.

Absolutely the best transmission in a super car I have ever driven. While my Callaway is fine for just driving around town the manual shift from the paddles both up and down have a terrible delay.

while in auto mode the Callaway shift very quick at wide open trottle but that is the only time it shift quickly.


​​The C8 midengine must have a DCT if it's going to have performance on part with the euro exotics.

If you have ever driven a well sorted DCT then you would have to agree that it's the only way to go for a performance super car.

If you looking for just luxury and don't care about shift speed then the TC Trans is fine. But make no mistake the folks that drive C7 with A8 and say it's as good as a DCT have never driven a well sorted DCT. There just no comparison.

Now if the only choice was the old automated Lambo single clutch vs the A8 TC in the C7 I would settle for the A8 any day of the week.

Lambo was smart and went to DCT with the Huracan because they know the old tech was no longer good enough.

​​​​​I would gladly pay an 10k premium for a well sorted DCT in the C8 midengine Z06 or Zr1 which with the pricing of the C7 Z cars everyone need to be prepared to pay 120k to 175k for a loaded up C8 Z06 OR ZR1.

ByByBMW

Thanks for a well written response. I have been touting the DCT, more specifically the Porsche PDK but don't have the chops that you have when it comes to explaining why.
For those that want another explanation of how the PDK in Porsche's work, here is a good write up.
https://www.excellence-mag.com/issue...3#.WiivLktryAM

Shaka

The 3rd dumbest.

OnPoint

Then refute it. The A8 has three clutches so named, and two brakes which also operate as torque transfer mechanisms - i.e. clutch.

SSsedanM6

Agreed.
Anyone who has tested these transmissions for themselves, or even has a basic understanding of physics, knows the above is true.

I am SO sick and tired of the lies and garbage that is posted on forums regarding DCT and the ridiculous assertion that torque converters are in the same league.
A lot of clueless morons and blatant liars are going to be eating a ton of crow over the next few years, and I hope they're held accountable.

RedLS6

I think most folks on here who know a little bit about transmission design knew exactly what OnPoint meant about 5 clutches, and exactly what JoesC5 meant about an input shaft. There's an old saying about a forest and some trees .....

NoOne

I'll just repeat what I said earlier:

Here is the take away.

People who have not driven a PDK/DCT say the regular auto is good enough.

People who have driven a PDK/DCT know better. I doubt you take any of the naysayers and put them in a car with a good DCT/PDK and they come out of thinking the TC trans is good enough.

Nobody who has any interest in performance at all after driving both will say the TC trans is good enough.