difference between Steptronic vs Double Clutch

[mtla4]

Originally Posted by JohnnyTT

I don't want to start up an automatic vs .... war.

But I've driven manuals my whole life, I've driven auto-clutches, and I'm driving my 135i with steptronic.

I would put this steptronic up against all the DSG/DCT trans out there and say the 135's steptronic shifts faster than everyone I've been in. The shifts are INSTANT!!!!..and lock up is INSTANT!!!!

Yes, as soon as a DSG/DCT comes out that is lightning fast, I will definitley jump on board. But I havn't driven one yet. I'm honestly extremely happy with my instant shifts.

Yes everybody, I do understand the feel of having a direct line to the engine. I do appreciate that raw feeling. But I'm all smiles in manual mode when I hit a turn in 3rd or 4th...and come flying out in 2nd, WithOut A Hint Of Hesitation.

I strongly disagree so why not put that tranny in M3,M5 etc. I dont know if you have driven DCT,DSG, Twin-Clutch SST but its in an other league. Steptronic still has a torque converter and will still upshift for you, will not hold gear and wont downshift fast. Whatever floats your boat but Im tired of people thinking that the steptronic(regular auto by the way)is faster than manual no way the car and driver road and track test were not done the same day,same condition same car and hell Ive never done two identical drag or lapping time yet. I dont want to attack you personally but I had to quote to explain my point. The only reason why DCT-DSG tends to be fast is that they do have a clutch system which regular auto does not.
http://www.carbibles.com/transmission_bible_pg2.html

[JohnnyTT]

Originally Posted by mtla4

I strongly disagree so why not put that tranny in M3,M5 etc. I dont know if you have driven DCT,DSG, Twin-Clutch SST but its in an other league. Steptronic still has a torque converter and will still upshift for you, will not hold gear and wont downshift fast. Whatever floats your boat but Im tired of people thinking that the steptronic(regular auto by the way)is faster than manual no way the car and driver road and track test were not done the same day,same condition same car and hell Ive never done two identical drag or lapping time yet. I dont want to attack you personally but I had to quote to explain my point.
http://www.carbibles.com/transmission_bible_pg2.html

I never said the car was faster, I never said it will hold a gear at redline, although I can hold right below it.

All I said was it shifts faster than most cars I've ever drivin with Autos or DCT/DSG's... from VW's, Audi's, Porches....

Drive one, you'll be shocked how fast it shifts and locks. I know I was, because I was nervous not getting a manual... my first car EVER without one.

[mtla4]

Originally Posted by JohnnyTT

I never said the car was faster, I never said it will hold a gear at redline, although I can hold right below it.

All I said was it shifts faster than most cars I've ever drivin with Autos or DCT/DSG's... from VW's, Audi's, Porches....

Drive one, you'll be shocked how fast it shifts and locks. I know I was, because I was nervous not getting a manual... my first car EVER without one.

Ive driven the 335 three times while I ordered this car in January and I almost passed on the car because it made the ride boring so the 1 being close to the 3 I didnt know what to do. The thing is that car is a GT and not a sports car so the automatic will do fine for most drivers.

[silversh]

Originally Posted by atr_hugo

The Steptronic transmission (and the other so-called manu-matic trannies) have torque converters. There is no direct physical coupling (other than transmission fluid) between the output of the engine and the transmission.

I thought the modern automatics all had mechanical lockup in the torque converter.

[RobLS]

Originally Posted by jayce

yes i mean the DCT is a transmission that normal auto trans ought to be.
it's just brilliant and so efficient.

but then i see DCT provided in only M3
and SMG provided in only M6

i see how SMG is better than DCT and DCT than Steptronic,
but just wondering does it really cost much more to make SMG and DCT than steptronic?

I thougth I remembered reading that bmw will introduce the DCT to the 335i Coupe this next year....

[atr_hugo]

Originally Posted by silversh

I thought the modern automatics all had mechanical lockup in the torque converter.

That's possible - I don't know for sure if that is the case with ZF or the GM auto in the 135/128 (supsect it is though). Regardless, it still employs the torque converter.

[jayce]

Originally Posted by RobLS

I thougth I remembered reading that bmw will introduce the DCT to the 335i Coupe this next year....

true, its 335 coupe&vert. they said they will, but they didnt yet.
i assume the dct being equipped on the 1er eventually too.

[RobLS]

Yeah, probably will trickle down to the other 3s and Zs then to the 135i. I thought the 550i and 6 series had something like that too... maybe that was their "sport" automatic, which I still enjoyed.

[warmtoes]

Originally Posted by atr_hugo

That's possible - I don't know for sure if that is the case with ZF or the GM auto in the 135/128 (supsect it is though). Regardless, it still employs the torque converter.

I remember reading that the Step in the 135 had the lockup so the torque losses were eliminated at launch.

[JohnnyTT]

Originally Posted by silversh

I thought the modern automatics all had mechanical lockup in the torque converter.

I just read a mechanical description of the step.... it has a mechanical lockup.

[MVF4Rrider]

Originally Posted by jkp1187

I was impressed with the shifts in the steptronic 128i as well as the Volkswagen GTI's DSG.

I was disappointed, however, that neither of them held the gear and let me bounce off the redline, even when in "manual" mode.

There's no point to bounce off the redline. Anyway, it's called throttle control which will keep you from letting the system select the next gear. Another advantage of DSG/DCT is that manual gearshifts mid corner do not upset the chasis like manual gearboxes when you interrupt power. And, you can short shift (so you stay heavy on the throttle) at relative ease which is a far faster way through and out of a corner than getting the wheels spinning or waiting to exit the corner before shifting. When watching F1 on-board footage, you'll notice lots of short shifting now that traction control is gone.

[RobLS]

Originally Posted by Balls

There's no point to bounce off the redline. Anyway, it's called throttle control which will keep you from letting the system select the next gear. Another advantage of DSG/DCT is that manual gearshifts mid corner do not upset the chasis like manual gearboxes when you interrupt power. And, you can short shift (so you stay heavy on the throttle) at relative ease which is a far faster way through and out of a corner than getting the wheels spinning or waiting to exit the corner before shifting. When watching F1 on-board footage, you'll notice lots of short shifting now that traction control is gone.

*nods* ditto

[MVF4Rrider]

Originally Posted by JohnnyTT

I never said the car was faster, I never said it will hold a gear at redline, although I can hold right below it.

All I said was it shifts faster than most cars I've ever drivin with Autos or DCT/DSG's... from VW's, Audi's, Porches....

Drive one, you'll be shocked how fast it shifts and locks. I know I was, because I was nervous not getting a manual... my first car EVER without one.

It's impossible to shift faster than DCT/DSG that pre-selects the next gear. If you don't know what you're doing and interpupt power (by lifting) when you change gears then yes DCT/DSG is slower because you tricked the system into thinking you didn't want to upshift (therefore, no gear pre-selection). Same goes for downshifting. You have to lift to let the system know you may downshift so it pre-selects the next lower gear. If you don't lift, the shift takes what seems forever and it's rather sluggish. After 25,000 miles in a DSG equipped Audi TT, I can assure you no torque converted autobox is anywhere close in shifting speed (up or down) to a dual clutch system. Not even close.

[jeremyc74]

Originally Posted by Balls

It's impossible to shift faster than DCT/DSG that pre-selects the next gear. If you don't know what you're doing and interpupt power (by lifting) when you change gears then yes DCT/DSG is slower because you tricked the system into thinking you didn't want to upshift (therefore, no gear pre-selection). Same goes for downshifting. You have to lift to let the system know you may downshift so it pre-selects the next lower gear. If you don't lift, the shift takes what seems forever and it's rather sluggish. After 25,000 miles in a DSG equipped Audi TT, I can assure you no torque converted autobox is anywhere close in shifting speed (up or down) to a dual clutch system. Not even close.

You're wrong about this. There will always be a point in a DSG where neither gear is enguaged, and the engine isn't transmitting full power to the wheels. Performance tuned automatic transmissions don't have that issue. Shifts occurr at full power.

The Lexas IS-F is currently the fastest production transmission as far as I know.

http://www.1addicts.com/forums/newre...reply&p=249659

Aft of the V8 is what Lexus says is the world’s first eight-speed sport direct-shift transmission. It, too, starts life as the unit from the LS. In this application, the torque converter locks in second through eighth gears in manual mode for more efficiency. The paddle-shift manual mode holds each gear to the 6800-rpm redline. Upshifts take a tenth of a second, the fastest for a production transmission, Lexus says. Downshifts come with a blip of the throttle for smoothness.

[Dr_Jones]

i shiver every time i see that dsg cutaway

[MVF4Rrider]

Originally Posted by jeremyc74

You're wrong about this. There will always be a point in a DSG where neither gear is enguaged, and the engine isn't transmitting full power to the wheels. Performance tuned automatic transmissions don't have that issue. Shifts occurr at full power.

The Lexas IS-F is currently the fastest production transmission as far as I know.

http://www.1addicts.com/forums/newre...reply&p=249659

I think you're a little off subject. Everything I stated is accurate. If you don't have personal experience you shouldn't comment. The topic is shifting speed, not transmission of power to the wheels. And if you want to learn about that, just go to the Haldex website. You'll be surprised as to what you learn.

[jkp1187]

Originally Posted by Balls

There's no point to bounce off the redline. Anyway, it's called throttle control which will keep you from letting the system select the next gear. Another advantage of DSG/DCT is that manual gearshifts mid corner do not upset the chasis like manual gearboxes when you interrupt power. And, you can short shift (so you stay heavy on the throttle) at relative ease which is a far faster way through and out of a corner than getting the wheels spinning or waiting to exit the corner before shifting. When watching F1 on-board footage, you'll notice lots of short shifting now that traction control is gone.

I would still prefer to leave the car in one gear and have it stay there until I choose to shift it, regardless of whether it's the wise thing to do, or whether I bounce off the redline. (Except shifting back to 1st at a full stop, I suppose.) If I have the thing in "manual" mode, it's because I want to go through the bother of exercising manual control over the shifts, so it annoys me to have the computer make decisions for me at that time.

[MVF4Rrider]

Originally Posted by jkp1187

I would still prefer to leave the car in one gear and have it stay there until I choose to shift it, regardless of whether it's the wise thing to do, or whether I bounce off the redline. (Except shifting back to 1st at a full stop, I suppose.) If I have the thing in "manual" mode, it's because I want to go through the bother of exercising manual control over the shifts, so it annoys me to have the computer make decisions for me at that time.

So you'd rather have the computer cut the power to the engine when you're demanding the most of it? Another beauty of the dual clutch system is it makes it impossible to overrev the motor. At the point of gear change it's beyond peak power and torque anyway. So even allowing the motor to reach that point serves no real purpose. I guess it would be an indicator for you to shift on your own. I use my ears, eyeballs and tach for that.

Ultimately I can see why someone would want to hold a gear without the surprise of a gear change, but I think hitting a rev limiter would be just as annoying as the inadvertent gear change, if not more. Considering these are cars designed for road conditions, not track conditions it's easy to see why they programmed the tranny brains the way they did.

It's all debatable and preference really. But I like the systems I've experienced just as they are.

[jeremyc74]

Originally Posted by Balls

I think you're a little off subject. Everything I stated is accurate. If you don't have personal experience you shouldn't comment. The topic is shifting speed, not transmission of power to the wheels. And if you want to learn about that, just go to the Haldex website. You'll be surprised as to what you learn.

You didn't bother to even read the link. The upshift speed on the Lexus is .1 second.

[jkp1187]

Originally Posted by Balls

So you'd rather have the computer cut the power to the engine when you're demanding the most of it? Another beauty of the dual clutch system is it makes it impossible to overrev the motor. At the point of gear change it's beyond peak power and torque anyway. So even allowing the motor to reach that point serves no real purpose. I guess it would be an indicator for you to shift on your own. I use my ears, eyeballs and tach for that.

I would rather the computer leave control of shifting to me when I put it in manual mode. If I want computer-assist, I'll leave it in automatic mode. If this means sub-optimal shifting, then so be it.