Quote:
|
Originally Posted by captainaudio
Quote:
Originally Posted by Needsdecaf
A few things that are different.
Some of the posters above are steering you off track. I mentioned the torque converter not because it's the only way to get smooth take offs, but because of HOW IT WORKS. A torque converter uses two "fans" essentially, spinning in fluid (ATF). Very simply put, the "fan" on the engine side spins as the engine speeds up. At first, nothing happens. But as the "fan" spins faster, the fluid's shear eventually starts to transmit force to the other "fan" and the wheels receive power. This is very gradual and soft, hence "smooth starts". At some point, the two sides will lock together using a clutch, and you will have no loss due to the heat in the fluid.
Because the DCT has no torque converter, it uses a clutch to engage the drive side (engine) to the driven side (wheels) (two actually, one for odd gears, the other for even). So it's engagement behaves the same way that a manual transmission would. Here is the difference.
In a traditional manual transmission, the driver is in charge of two things, throttle and clutch. You choose how many revs to add, and how quickly or gradually to engage the clutch. You control the smoothness of the engagement.
In the DCT, you still control the throttle, but the computer controls the clutch. It needs to guess your intentions based on throttle input. So, if it senses you rolling into the throttle, it'll engage the clutch slowly. Jam into the throttle, and it'll slam the clutches shut, expecting that you'll want a fast takeoff.
So the trick is that you need to work simpatico with the computer that's engaging the clutch. Since there is no fluid filled torque converter damping out any differences, you're going to feel when you and the computer are at odds with one another.
I won't get into shifting underway, as that's usually not as much of an issue.
Hope this helps.
|
This is a very good description but will stick to my point that if you put the car in drive and are conservative with the throttle the DCT will act very similar to a Steptronic. |
Yes, it quickly (to me) becomes second nature as to how the computer is going to react, and it works much like a normal automatic. But better. But the poster I was responding to wanted to know what was different, and what differences to expect. Pretty much, if he follows the thought of what I wrote, he will never have issues with jerkiness. As others mentioned, there is no creep, and if you feed in the throttle slowly,,you'll get a sense of the clutch biting. You do not get this sense with a torque converter auto.
As I said, and as you alluded to, once underway, shifts in D1 are very similar to those of the ZF8. Downshifts are noticeably better, IMO.