F1 gear box v. our DCT

[Ateam]

Just watched the dubai grand prix and was thinking that the dct does not "sound faster" in how it shifts and I do not know how you can really continue to get any faster than our dct given there is already absolutely no loss in power with the change and it is instant changing. Obviously there are probably a million other differences such as I just heard a piece how they actually have 2 clutches that they can operate independantly manually or have it in the computerized clutch mode. Did not know this but in their launches
they actually manually operated their foot clutches or something as it was an interested piece on why there is such variation in webbers piss poor starts but great driving!

ANyone else knows what their tranny do differently or are they a totally different animal? Other than being way stronger obviously

[MUFCbmwbear]

Crap, I forgot to set the DVR for the race.

[IFX]

good question.. i guess this is something to consider.. when SMG came out, everyone thought it was amazing. DCT came out, and now SMG is ass in comparison.

I'm basically saying DCT could be ass compared to whatever those boys are pushing...

[redline9001]

In F1 they are required by the rules to interrupt the power between shifts. When Williams first devolped the tranny it had no power interruption but got banned.

It is hard to know the details between the two but I would think they are close enough in design....

[BMW Fanatic]

Originally Posted by redline9001

In F1 they are required by the rules to interrupt the power between shifts. When Williams first devolped the tranny it had no power interruption but got banned.

It is hard to know the details between the two but I would think they are close enough in design....

+1

[Ateam]

so that means our are better well maybe in one small way! But I sure do not see much interuption in power when you watch! Must be so minute

[I M STIG]

Originally Posted by redline9001

In F1 they are required by the rules to interrupt the power between shifts. When Williams first devolped the tranny it had no power interruption but got banned.

It is hard to know the details between the two but I would think they are close enough in design....

Also, the have a manual clutch to operate with their fingers. So each pull of a paddle, they have to be holding the clutch paddle on the steering wheel, as well.

So the DCT is technically faster, but it's not, simply by the design of the cars the DCT goes in to versus the sequential gearboxes F1 use.

Here's a picture of the F1 wheel with the clutch and shift paddles present.

[OldenburgerM3]

There are two manual clutch levers on the F1 cars, both only used during the start, and both on the steering wheel. One clutch is carefully manipulated and the other one dumped during the start. The tolerances are extremely tight and the clutch bite points are set during the recon lap before the start. Any fluctuations in ambient conditions will change the bite-point and therefore compromise the starts. While the driver has a lot of influence on the F1 start, the background technical wizardry needs extremely careful setup.
During the race, the gearbox shifts seamlessly. There are no clutches. You can't say how long it takes to shift gears in F1 because it's seamless, but "the total travel of the dog ring between a neutral state and an engaged state takes around seven thousands of a second."
Design, testing, and production of an F1 gearbox takes 3-3.5 million pounds for the eight gearboxes for the season, additional ones are estimated at 200.000 pounds.

[signes]

Great summary. To the OP F1 boxes are more akin to a traditional sequential manual - the only thing they have in common with DCT is paddle actuation.

[Serious]

Originally Posted by AwesomeBMW2

Also, the have a manual clutch to operate with their fingers. So each pull of a paddle, they have to be holding the clutch paddle on the steering wheel, as well.

Not true. The clutch paddles are used solely for the launch and anytime the car needs to be started from rest. The system is still quite SMG like in design (single clutch system) the dual paddles during launch sequence are used to determine via clutch engagement how much torque is sent to the rear wheels since initially the car is traction limited, once it passes about ~60mph the second clutch paddle is progressively released which increases the amount of clutch engagement until fully released. This is how an f1 car controls wheelspin without an automated launch control system.

As for shifting the gearboxes are often able to seamlessly shift (no clutch movement) which is performed faster than a DCT box can complete a shift action, although occasionally the system can fault and a clutched shift is performed which is probably equal speed to a DCT shift.

BTW in terms of strength you have to remember that a modern v8 f1 engine only makes ~225lbft of torque and given the drive to reduce weight and reduce packaging volume I would bet the gears themselves aren't much if at all higher strength than the ones in any modern sports car. The biggest difference outside of the actual design is probably the construction materials within the boxes themselves. Probably lots of titanium and exotic alloys.

[IS350]

Anyone know the time between button pushes and full gear engagement on our DCT cars?

[mkoesel]

Originally Posted by signes

Great summary. To the OP F1 boxes are more akin to a traditional sequential manual - the only thing they have in common with DCT is paddle actuation.

Not sure I'd agree. They have two independently operating clutches so its sounds like a DCT to me. Also, I doubt they are mechanically limited to sequential shifting like a true sequential manual gearbox is.

Regarding the F1 gearbox, I am curious now. Does anyone know:

- how many speeds they have
- if they are wet clutch or dry clutch
- if the clutches are concentric like a DCT (I have to assume yes)
- if they can skip gears

[M3SQRD]

Here's a video by Mercedes GP discussing a modern F1 gearbox:

The gearbox uses a "conventional" dry multi-disc carbon clutch plates (a total of seven, i think) with an outside diameter of ~4". The transmission design is a lot closer to a motorcycle sequential gearbox than a road car (conventional or DCT) and, no, they cannot skip a gear. Other than using paddles to shift gears an F1 gearbox is nothing like our DCT.

[SenorFunkyPants]

F1 rules forbid the use of Dual clutch gearboxes.

[I M STIG]

Originally Posted by Serious

Not true. The clutch paddles are used solely for the launch and anytime the car needs to be started from rest. The system is still quite SMG like in design (single clutch system) the dual paddles during launch sequence are used to determine via clutch engagement how much torque is sent to the rear wheels since initially the car is traction limited, once it passes about ~60mph the second clutch paddle is progressively released which increases the amount of clutch engagement until fully released. This is how an f1 car controls wheelspin without an automated launch control system.

As for shifting the gearboxes are often able to seamlessly shift (no clutch movement) which is performed faster than a DCT box can complete a shift action, although occasionally the system can fault and a clutched shift is performed which is probably equal speed to a DCT shift.

BTW in terms of strength you have to remember that a modern v8 f1 engine only makes ~225lbft of torque and given the drive to reduce weight and reduce packaging volume I would bet the gears themselves aren't much if at all higher strength than the ones in any modern sports car. The biggest difference outside of the actual design is probably the construction materials within the boxes themselves. Probably lots of titanium and exotic alloys.

You, sir, are correct. I could have sworn I was told they had to pull the clutch, too. Guess I was wrong. Thanks for clearing it up.

[Ateam]

That video also says there "is no interuption in power" so whoever said that is not allowed is clearly wrong. I actually thought they used a Dual clutch gearbox all race so this is also new to me. I knew there was some funny business about the start which makes sense since if it was as simple as "launch control" there would not be such a variance consistently among good starters and bad. Poor webber is plagued by the start. Must be so frustrating being vettel's teamate.

All is interesting to me though, I guess it is not so senseless that the new lambo has a classic SMG and not dct as that is truly more race tech than the dct. Learn something on these boards every day!

[Serious]

Originally Posted by mkoesel

Not sure I'd agree. They have two independently operating clutches so its sounds like a DCT to me. Also, I doubt they are mechanically limited to sequential shifting like a true sequential manual gearbox is.

Regarding the F1 gearbox, I am curious now. Does anyone know:

- how many speeds they have
- if they are wet clutch or dry clutch
- if the clutches are concentric like a DCT (I have to assume yes)
- if they can skip gears

they do not have 2 independently operated clutches, they have two paddles for one clutch. dual clutch systems are not allowed in F1 since it could potentially be used as a CVT. They are allowed 4-7 forward speed, a multiplate dry clutch, and the gears are lined up sequentially within the box... whether they have the ability to skip gears I would assume so.

[mkoesel]

Originally Posted by Serious

they do not have 2 independently operated clutches, they have two paddles for one clutch. dual clutch systems are not allowed in F1 since it could potentially be used as a CVT.

Gotcha. My bad there, I thought someone had mentioned earlier that they are indeed DCTs.

They are allowed 4-7 forward speed, a multiplate dry clutch, and the gears are lined up sequentially within the box... whether they have the ability to skip gears I would assume so.

Yeah, that sounds like a typical sequential manual racing transmission to me. But I don't think those are able to skip gear, AFAIK. I think they are like a motorcycle where the shift forks are activated by a rotating shaft that clicks them in and out of gear in order (spin it one way to downshift, spin the other way to upshift - and that's it). This is far less complicated than a DCT or even BMW's "SMG" where each fork is connected to its own linkage that in turn is actuated electro-hydraulically. In theory it makes the whole thing more durable and reliable.

[signes]

Originally Posted by mkoesel

Not sure I'd agree. They have two independently operating clutches so its sounds like a DCT to me. Also, I doubt they are mechanically limited to sequential shifting like a true sequential manual gearbox is.

Regarding the F1 gearbox, I am curious now. Does anyone know:

- how many speeds they have
- if they are wet clutch or dry clutch
- if the clutches are concentric like a DCT (I have to assume yes)
- if they can skip gears

Here are the transmission regs from the FIA. 7 forward speeds for all on the grid this year. I don't believe they are allowed to skip gears any more but there is nothing in the rules I saw to prohibit that.

[Serious]

here is a breakdown of how the 'zeroshift' boxes work...

http://www.zeroshift.com/pdf/RcarN6V15_Zeroshift.pdf

I assume this is similar to the method the F1 teams are using to operate the seamless shift boxes.

[///My5UV]

FYI, most (I'm not sure about F1) racing gearboxes have tougher (louder) straight-cut gears that can take shifting without use of the clutch. That's been true for over 20 years. Still, the revs have to be matched on any shift (up or down) and making that fast depends on lightened components (flywheel, clutches, crankshaft, pistons, etc) and carefully tuned software.
Most racing gearboxes I've seen make more noise than a street car's engine :-)