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What is the 7-speed manual gearbox?

 
Old 03-20-2013, 01:56 PM
  #1  
Carrera GT
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Default What is the 7-speed manual gearbox?

Aside from one or two pages of superficial information, I've not see a full "blood and guts" examination of the new 7-speed manual box. Perhaps someone out there in Rennlist land can offer up a PDF or a link, please?

I realize it has auto-blip and start-stop capability, but I'm not completely clear on whether the driver has the direct actuation of the clutch or if this is now a "clutch by wire" and the pedal is a simulation of some sort.

Comparing this to the Koenigsegg gearbox, you really see one is a luxury GT car box, a feat of production engineering, shared components, modular design, and ZF refinement showcased in all its splendor; the other is a sports car ("hypercar"?) box. Coincidentally, on the last link, there's another page that describes the truck transmission technology that does the same as the "invention" of the clutch brake in the 'seg box. But I digress ů

ps. Here's what I found interesting, but little else:

http://www.zf.com/corporate/en/produ...smission.shtml

http://www.sae.org/mags/sve/10374/

http://www.torquenews.com/119/porsch...smission-world

http://www.caranddriver.com/features...-pdk-tech-dept

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Old 03-20-2013, 02:05 PM
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I just hope that when the Porsche people tell us that the GT3 991 7spd gearbox is "new" that it is just marketing and that it really is just different ratios and/or final drive. Having just completed design and manufacturing of a proper LSD for the 911 Carrera 7spd, I am going to be mildly miffed if we have to design and build yet another LSD for the GT3...
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Old 03-20-2013, 02:12 PM
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Originally Posted by GTgears View Post
I just hope that when the Porsche people tell us that the GT3 991 7spd gearbox is "new" that it is just marketing and that it really is just different ratios and/or final drive. Having just completed design and manufacturing of a proper LSD for the 911 Carrera 7spd, I am going to be mildly miffed if we have to design and build yet another LSD for the GT3...
Great to have you contribute here. If you would, when you get a chance, check out the Koenigsegg box in this thread:
https://rennlist.com/forums/991-gt3/...l#post10316945
and perhaps you can share your perspective.

If Porsche can OEM from ZF to build PDK and the 7-speed manual single clutch, why not just offer the option to bid on an OEM contract for Koenigsegg to deliver that clutch-brake dog box with hydraulic diff? I know I'm dreaming, but hell.

Seeing that 'segg box really has me salivating ů
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Old 03-20-2013, 02:14 PM
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Are your LSD's not mostly bought by track junkies?
I wouldn't worry about it.
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Old 03-20-2013, 02:30 PM
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Originally Posted by TRAKCAR View Post
Are your LSD's not mostly bought by track junkies?
I wouldn't worry about it.
That's just cruel!
<insert obligatory disambiguation smilie>

Some track junkies will still buy the GT3 and the RS and whatever the hell comes next. Unless it has a hybrid drive in it. That's where I draw the hard line. All-wheel drive. All-wheel steering. Okay, okay. PASM, PSM, these are all straws on the camels back.But batteries and electric motors and leviathan curb weight. No.

To quote someone far wiser than myself quoting someone far wiser than himself:

To me, we have a hard line on the race track, not a line in the sand, not a moving boundary of intrusion. We have the inviolate, immutable essence of the 911. To quote Picard, "This far, and no farther!"
Furthermore:


Last edited by Carrera GT; 03-20-2013 at 02:34 PM. Reason: comedy, not serious!
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Old 03-20-2013, 02:34 PM
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Haha, ok i didn't really cancel my RS deposit shhh..
Unless it has hybrid crap, than Im out.
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Old 03-20-2013, 02:38 PM
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Originally Posted by TRAKCAR View Post
Are your LSD's not mostly bought by track junkies?
Actually, most of our parts are purchased by club racers. The track day DE Cup movement of the last couple of years is a pretty new market development. We manufacture parts for racing. The fact that they have been repurposed for track toys isn't going to sway our focus.

But none of that changes the fact that the 991 factory LSD is just as anemic as other recent LSDs and not appropriate for track usage. So, even if someone ordered an LSD with their vehicle new, it's not going to work very well. And with the GT3 coming stock with an LSD, it's going to become immediately apparent to you track junkies that it is not up to the task.

Then the problem becomes that my ability to service your street car LSDs is only because they share the same inner dimensions as a Cup Car LSD. With the 991 that cross compatibility is out the window. Just like all the Cayman and Carrera owners, any of you guys who buy a 991 GT3 are going to be shopping for an all new LSD to replace the factory doorstop.

Originally Posted by Carrera GT View Post
If Porsche can OEM from ZF to build PDK and the 7-speed manual single clutch, why not just offer the option to bid on an OEM contract for Koenigsegg to deliver that clutch-brake dog box with hydraulic diff? I know I'm dreaming, but hell.
The problem is clearly one of cost. I'm not sure who designed and is manufacturing that Koenigsegg box, but I have a good idea. And you can be sure that the gearbox costs more than a complete 991 GT3 is going to cost. That's just the bottom line hard truth to the 911. The 911 has never been a hypercar and never wll be. Porsche is going to reserve that cost and escelon of technology for their own hypercars.
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Old 03-20-2013, 02:43 PM
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Originally Posted by TRAKCAR View Post
Haha, ok i didn't really cancel my RS deposit shhh..
Unless it has hybrid crap, than Im out.
Deposits mean nothing unless you stroke the purchase check it hasn't happened.

Peter
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Old 03-20-2013, 05:24 PM
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Originally Posted by GTgears View Post
Actually, most of our parts are purchased by club racers. The track day DE Cup movement of the last couple of years is a pretty new market development. We manufacture parts for racing. The fact that they have been repurposed for track toys isn't going to sway our focus.

But none of that changes the fact that the 991 factory LSD is just as anemic as other recent LSDs and not appropriate for track usage. So, even if someone ordered an LSD with their vehicle new, it's not going to work very well. And with the GT3 coming stock with an LSD, it's going to become immediately apparent to you track junkies that it is not up to the task.

Then the problem becomes that my ability to service your street car LSDs is only because they share the same inner dimensions as a Cup Car LSD. With the 991 that cross compatibility is out the window. Just like all the Cayman and Carrera owners, any of you guys who buy a 991 GT3 are going to be shopping for an all new LSD to replace the factory doorstop.
Given that it's claimed to be electronic fully variable diff and housed within automatic should we even expect it to be anything like manual tran diff?

Last edited by Nizer; 03-21-2013 at 12:35 PM.
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Old 03-20-2013, 05:45 PM
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Originally Posted by GTgears View Post
Just like all the Cayman and Carrera owners, any of you guys who buy a 991 GT3 are going to be shopping for an all new LSD to replace the factory doorstop.
That's great news!

Here I was thinking I'd have junk in the trunk, but no, the factory LSD will function as a doorstop.

Why isn't this in the Preuninger interview?
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Old 03-20-2013, 06:04 PM
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Originally Posted by 85Gold View Post
Deposits mean nothing unless you stroke the purchase check it hasn't happened.

Peter
It has not happened. But it must be very special to be more fun than a 4.0 or a GT2RS..


Originally Posted by Nizer View Post
Given that it's claimed to be electronic fully variable diff and housed within automatic should we even expect to be anything like manual tran diff?
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Old 03-20-2013, 07:25 PM
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Originally Posted by GTgears View Post
Just like all the Cayman and Carrera owners, any of you guys who buy a 991 GT3 are going to be shopping for an all new LSD to replace the factory doorstop.


Good old Porsche, the deep, lube-free penetration never ends does it.

Lol...

Follow-up edit- they actually do have a real e-diff, I stand corrected and fully lubed!

Last edited by savyboy; 03-22-2013 at 07:32 PM. Reason: recognize facts
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Old 03-20-2013, 07:39 PM
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Originally Posted by Nizer View Post
Given that it's claimed to be electronic fully variable diff and housed within automatic should we even expect to be anything like manual tran diff?
That was what I meant when I wondered out loud how much of it is marketing and what is really inside the box. That could just be Porsche speak for more ABD and PSM and traction control or it could mean that they have finally released a trick cutting edge truly dynamic LSD with on the fly variable locking adjustment like is in the Koenigseggseggsegg.

The LSD in the Koenigsegg is the coming wave of high tech differentials. We could make one, but the reason we haven't is that in motorsports those active differentials are generally banned.
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Old 03-20-2013, 07:42 PM
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Originally Posted by savyboy View Post


Good old Porsche, the deep, lube-free penetration never ends does it.

Lol...
I've given up trying to understand the interface between the bean counters and the designers at Porsche. Do you know that they make two different castings of the case for the factory LSD PDK gearbox versus the open differential PDK gearbox? The open diff box is 4mm narrower across for some reason. If they are trying to be efficient and cost effective with their legos, why are they running two castings when just one would work fine???
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Old 03-20-2013, 08:05 PM
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Originally Posted by GTgears View Post
That was what I meant when I wondered out loud how much of it is marketing and what is really inside the box. That could just be Porsche speak for more ABD and PSM and traction control or it could mean that they have finally released a trick cutting edge truly dynamic LSD with on the fly variable locking adjustment like is in the Koenigseggseggsegg.
PTV+ is also available (in fact it was available first) on the Cayenne. The electronically controlled diff which is part of the package can be manually locked from the center console of the SUV for off road use. This would seem to indicate that at least it's not using the brakes as is done with ABD, TC, and PSM, and implies something more sophisticated; perhaps the variable on-the-fly electronic diff Porsche claims it is. I'm no expert; what do you think?

Last edited by Mike in CA; 03-20-2013 at 09:16 PM.
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