twin clutch transmissions, like DSG, GT-R...

[BlahBlahYouToo]

so i read that these dual clutch transmissions have 2 clutches for odd and even gears.
when you're in a certain gear, the next gear is already pre-selected making for lightning quick shifts.

i take it that means if you've in 3rd, 4th is the pre-selected gear.
what if you downshift instead of upshift. does that result in a slower shift?

 

[KDKPSJ]

Well, that's one thing that really depends on manufacturer. Depends on how they managed to program the computer to predict the driver's selection.

As you know, the onboard computer predicts the driver's behavior. Shifting into non-next gear might be slightly slower than shifting into next gear, but it still would be fast enough, so the driver wouldn't realize. Also, as DSG becomes advanced and improved, it predicts the driver's behavior better and better, and it even predicts the driver might downshift. It's really how manufacturer programed the computer, so that's why it really depends on the manufacturer's know-how and tranny experience.

 

[Kabob]

I assume it takes the rpm's into account, if you're accelerating it'll predict an upshift, while if you're braking or coasting it'll predict a downshift...

 

[thomsbrain]

Originally posted by: kabob983
I assume it takes the rpm's into account, if you're accelerating it'll predict an upshift, while if you're braking or coasting it'll predict a downshift...

That's the gist of it.

 

[Demon-Xanth]

Originally posted by: kabob983
I assume it takes the rpm's into account, if you're accelerating it'll predict an upshift, while if you're braking or coasting it'll predict a downshift...

Cars have also had throttle position sensors and kick down cables for automatic transmissions for a long time.

on throttle=shift up
off throttle=shift down

 

[Howard]

Originally posted by: kabob983
I assume it takes the rpm's into account, if you're accelerating it'll predict an upshift, while if you're braking or coasting it'll predict a downshift...

It also takes time for the engine to match revs, so it's not an excessive delay.

Generally, 6th to 2nd is the slowest shift in a DSG.

 

[Hyperlite]

Originally posted by: Howard

Originally posted by: kabob983
I assume it takes the rpm's into account, if you're accelerating it'll predict an upshift, while if you're braking or coasting it'll predict a downshift...

It also takes time for the engine to match revs, so it's not an excessive delay.

Generally, 6th to 2nd is the slowest shift in a DSG.

which the average driver will probably never do, unless they do a brake stand from 80mph in automatic mode.

 

[overst33r]

Originally posted by: Howard

Originally posted by: kabob983
I assume it takes the rpm's into account, if you're accelerating it'll predict an upshift, while if you're braking or coasting it'll predict a downshift...

It also takes time for the engine to match revs, so it's not an excessive delay.

Generally, 6th to 2nd is the slowest shift in a DSG.

I didn't know you could skip gears in a DSG.

EDIT: sweet, because 6th and 2nd are on the same shaft and farthest away from each other. I guess 1st and 7th would work on the same principle, but even more strenuous.