Perhaps those Caymans had Porsche Torque Vectoring

They're part of the Sport Chrono option on the new 981. On paper, this sounds like it would be a good option in terms of handling. I haven't had a chance to try it with a manual transmission car to see what difference it would make. I did try it with a PDK equipped car the day I went for a test drive, but with the PDK, I just couldn't get a feel for what was doing what.

Not likely anyone has had experience with this yet since it's just a new option. Thoughts?

My other question is the reliability. Are these something that's going to wear out and become very expensive to replace at some point?

[www.porsche.com]

I had the same questions, Guenter.

IIRC,GM has gone with a magnetic fluid in their shocks to provide variable damping; this might be the same type of application. If they are doing this on a tranny mount, wouldn't you expect this in a motor mount also--for the same reasons? Given this is a Porsche, I would expect repairs/replacement of the parts of this system to cost a multiple of the standard mounts.

Regarding the issue of firming up the tranny mount to keep the car on line in a turn, my first question is how much more does this add to enhancing the stability of the car and wouldn't a firmer rubber/poly mount work as well without the complexity if you really needed it?

Last, the Sport Chrono package--with the latest additions--is getting pricey; up to $1800 from roughly $900 when we got it on the 06. The ability to make the PSM less intrusive when you want it is useful to me, the quick throttle a bit less so, the stopwatch not at all and the active tranny mounts--??. I wish they would have paired the less intrusive PSM with the PASM as a standard feature in sport mode--the two would seem to go together.

Good points, Mike.

The Boxster which its mid engine layout has one engine mount and two tranny mounts where the 991's, having the engine at the back, have two engine mounts.

I have a feeling that the extra $900 for Sport Chrono is the cost for the dynamic tranny mounts. So you could imagine replacement cost. I'm not sure either, how much difference it would make to handling. One way or another, the weight of the engine and tranny is going to want to push out in a corner.

As far as PSM, for more driver control, I think you actually want it turned off (althought it's still there just in case) for less intervention in track driving.

There are times when the less intrusive PSM is a plus, like when you're at a new track; after I feel more comfortable, I'll turn it off, but the mid-level of involvement is helpful for me. BTW, even if you turn off PSM, it comes back if you're braking hard enough to engage the ABS. There was a thread on the Cayman board about this with people turning off their PSM at the track, but still wearing down their rear pads and wondering what was going on.

I know it runs counter-intuitive with Porsche's view of things--like driver involvement, but I like GM's stability control setup on the C6 ZR-1 and Camaro ZL-1. IIRC, it has 5 settings, ranging from a wet road setting to off, with three settings in between. Lot's of room for experimentation before turning the system completely off.

It combines limited slip with braking of the inside rear wheel.

Minus 40 degrees... Is that Fahrenheit or Celsius?

Quote
Laz
It combines limited slip with braking of the inside rear wheel.

Since the cars in question were Gen1 Caymans (2006-8 MY), my guess would be they didn't have the PTV.

Porche's Dynamic Engine Mounts have been getting rave reviews, so I'd assume the same would hold true for the Tranny mounts. I'm sure one day both will become standard on higher-end vehicles to make their rides all the more smooth. A possible downside to both (engine and gearbox mounts) is could they hide vibrations that may clue you into potential mechanical issues with the drivetrain?

From the Porsche link that Guenter provided,

"The gearbox is bolted to the body by two mounts. Like any mass, it obeys the law of inertia. This means that it will continue moving in a uniformly straight line unless some force causes it to change direction. Put more simply: when you are driving into a bend, the vehicle will follow your steering but, at first, the mass of the drive train will not. This means that the rear of the vehicle will ultimately be pushed outwards as a result of the drive train’s force of inertia. Dynamic gearbox mounts minimise this effect."

LIke any mass, it obeys the laws of inertia, but the DGM somehow changes (minimizes) those laws? How is that?

Quote
Bobtesa
From the Porsche link that Guenter provided,

"The gearbox is bolted to the body by two mounts. Like any mass, it obeys the law of inertia. This means that it will continue moving in a uniformly straight line unless some force causes it to change direction. Put more simply: when you are driving into a bend, the vehicle will follow your steering but, at first, the mass of the drive train will not. This means that the rear of the vehicle will ultimately be pushed outwards as a result of the drive train’s force of inertia. Dynamic gearbox mounts minimise this effect."

LIke any mass, it obeys the laws of inertia, but the DGM somehow changes (minimizes) those laws? How is that?

That's exactly what I was wondering.

Guenter
2014 Boxster S
GT Silver, 6 Speed Manual, Bi-Xenons, Sports Suspension (lowers car 20mm), Porsche Sports Exhaust, Porsche Torque Vectoring, Auto Climate control, heated and vented seats, 20" Carrera S Wheels, Pedro's TechNoWind, Sport Design steering wheel, Roll bars in GT Silver
[www.cyberdesignconcepts.com]

From a Porsche link on the dynamic engine mounts; I'd guess the tranny mounts use the same technology:

www.porscheengineering.com/.../Porsche-Download.pdf?...

"This is the result of a change in the hardness of the mount caused by a magnetizable (magneto -rheological) liquid and an electrically gen -
erated magnetic field."

That should clarify it; a fellow by the name of Tom Swift has the patent on it.



Edited 1 time(s). Last edit at 07/07/2012 09:45AM by MikenOH. (view changes)

Quote
MikenOH
From a Porsche link on the dynamic engine mounts; I'd guess the tranny mounts use the same technology:

www.porscheengineering.com/.../Porsche-Download.pdf?...

"This is the result of a change in the hardness of the mount caused by a magnetizable (magneto -rheological) liquid and an electrically gen -
erated magnetic field."

That should clarify it; a fellow by the name of Tom Swift has the patent on it.

That may be where some extra stability comes in. When the transmission mounts become stiffer it makes the car more stable, but transmits more drivetrain vibration into the car. I guess that would be like the "enthusiast" front engine mount that Pedro developed. The the Dynamic Gearbox mounts would be self adjusting between softer and harder setting.

... was missing something!
A couple of magnets.
I should have called it the Techno-Magneto-Rheological-Front Engine Mount.
Missed one there
Happy Boxstering
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

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"If you wait, all that happens is that you get older"... Mario Andretti

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High frequencies like engine and gearbox vibrations. Soft mounts allow the mass of the drivetrain to continue to move in the direction the car was going, then catch up. I forget how to describe this as physical properties... vectors, hysteresis, inertia, etc. Stiff mounts cause the drivetrain to more instantaneously follow where the chassis/body of the car is going. Imagine an unsecured bowling ball throwing its weight around because it's still moving in the old direction while a vehicle is braking, accelerating or turning. Even in a constant radius turn, more parts of the drivetrain are kept in "spec" by not having shifted as much away from their static ideal. Under braking, the drivetrain mass of our rear biased cars will have less tendency to lift. The inertial laws haven't gone away, it's just that all the pieces subject to them are working together.

Minus 40 degrees... Is that Fahrenheit or Celsius?



Edited 1 time(s). Last edit at 07/07/2012 02:05PM by Laz. (view changes)

Minus 40 degrees... Is that Fahrenheit or Celsius?