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Discussion Starter #1 (Edited)
A fairly neutral and well-balanced car (like the 981) with an open diff steers pretty well.

Adding locking diff to that, is gonna make it want to "push" (understeer) the front tires when you're on the throttle (up to the limit of rear-end traction, of course).

So my theory, is that Porsche installed the PTV electronic tom-foolery, to use the inside rear brake to cancel out the diff's push, making the car steer like it's got an open diff, while still providing all the benefits of a locking diff.

Am I getting it?
 

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Or just look at it as differential braking.

Some airplanes, like the Cirrus, don't even have a steerable nosewheel. All turns are done by differential braking.
 

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Discussion Starter #3 (Edited)
But I still have a question, and that is, does this differential braking simply counteract the force of the diff as the diff tries to push the nose wide? That would probably feel rather organic and natural. Or does that differential braking actually try to figure out what you're in the process of doing with the steering wheel, and proactively attempt to force the car (using the inside rear brake) into a tighter arc than a car with an open diff would carve? That would probably feel rather artificial and unnatural.
 

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But I still have a question, and that is, does this differential braking simply counteract the force of the diff as the diff tries to push the nose wide? That would probably feel rather organic and natural. Or does that differential braking actually try to figure out what you're in the process of doing with the steering wheel, and proactively attempt to force the car (using the inside rear brake) into a tighter arc than a car with an open diff would carve? That would probably feel rather artificial and unnatural.
That is my understanding, find the video on the Porsche website and that is what it describes...

I don't see it on your list of options?
 

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Discussion Starter #5
That is my understanding, find the video on the Porsche website and that is what it describes...

I don't see it on your list of options?
Define "That". The former, or the latter?

Porsche's description is not exactly helpful- it's like it was translated from German, into Ilocano, and then translated into English.

I'm still on the fence. It is an X73 car, but it's also a 2.7.
 

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My limited experience with PTV is that I don't feel the push, but I do feel the line tightening by magic. I rarely get in that realm, but I'm glad I got it. I think of it as a bit more Porsche pixie dust.
 

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my understanding is that the locked diff takes over on acceleration while the differential braking is more active on turn in... but i maybe kidding myself.
Regardless, after 5000 mi on my CGTS with PVT, -- with some spirited driving and a couple track days, I don't get the front understeer being discussed. Rather, I get nice turn in and can power out of corners.. at least to my level of driver competency.
D
 

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Wings of butterflies.

Get the car. Drive it. You could never discern the difference in everyday use. Or, likely, any other.
:cheers:
 

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Some airplanes, like the Cirrus, don't even have a steerable nosewheel. All turns are done by differential braking.
Been flying one of those. *Full Power* "RIGHT RUDDER RIGHT RUDDER RIGHT RUDDER MORE RIGHT RUDDER"
 

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Your thinking is not wrong, but lets remember that the locking both on accel and overrun is not very aggressive on these cars. i think its like...27% on acceleration right??

The PTV would be used to help correct DRIVER error, IE entering a corner too fast, or using gas too soon, or whatever.

With a more aggressive differential you may be more correct though.
 
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Hi. Christian the driver at Porsche made some videos which you can find in this link to Flat Six website Do Porsche's PTV Plus, Sport Chrono and PDCC Options Really Make A Difference? - @FlatSixes - the blog about Porsche Funnily enough the more widgets the car has the faster he goes. But the PTV does make sense re rotating the car but you can do that with a dab of left foot braking, just it's automatic and biased to the inside. Looks like the system is linked to steering input with algorithm factoring in speed and power. I'd say it is a performance option and not a safety one. So what happens if you enter corner at PTV max speed in non PTV car? Understeer I'd guess and back off the gas gently or get the oversteer to follow.
:drivingskid:
 

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Discussion Starter #14
Your thinking is not wrong, but lets remember that the locking both on accel and overrun is not very aggressive on these cars. i think its like...27% on acceleration right??

The PTV would be used to help correct DRIVER error, IE entering a corner too fast, or using gas too soon, or whatever.

With a more aggressive differential you may be more correct though.
Makes sense.

Plus, because of the wimpy carbon frictions in the Porsche locking differential, it's gonna wear out and be functioning just like an open diff by about 30,000 miles anyway.

I guess the only way to get a good locking diff in these cars, is to buy a Guard locking diff and install it.
 
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