The mastery of arithmetic on this forum continues to blow me away. PTV has the ability to brake individual wheels, thereby creating a moment, which is something a single brake pedal doesn't allow.

The mechanism of PTV and trailbraking is not the same. PTV provides a moment, and trailbraking provides weight transfer. You do not have to be braking to reap the benefits of PTV.

The same principals of physics apply whether you think your God's gift to motorsport, like VR does, or not.

 

Hoo boy.

First statement: not true. TB really provides adjustable rotation.

Second statement: the word is PRINCIPLES, genius, not PRINCIPALS. They are vastly different words. Also, the word is YOU'RE, not YOUR...also vastly different words.

And...um...you said my statements were "ignorant"? BWHAHAHAHAHAAAAA!!

As I said, PTV+ is for folks who can't trail brake.

PS: thanks for erroneously claiming to know what I think.

 

You're right about PTV+. Both PTV and PTV+ apply the brake on the inside rear wheel when the steering wheel is turned at low and moderate speeds to help rotate the car into the turn. PTV uses a mechanical locking diff, PTV+ an electronic one. You're wrong about PASM. It has nothing at all to do with braking. PASM is an electronic damping control system that adjusts the shocks based on road and driving conditions.

 

Actually Chuck, both PTV and PTV+ brake the inside rear wheel in a turn to rotate the car. The difference is that PTV does this in conjunction with a mechanical differential lock while + uses an electronic one.

 

Yes, I believe this is correct.

 

I won't contest your statement about principal and principle, but when you say PTV+ is for folks who can't trail brake that is incorrect. PTV works by momentarily braking just the inside rear wheel at turn entry which causes more drive force to be applied to the outside rear wheel, providing a brief boost helping to rotate the car into a turn. Trail braking is when all 4 brakes are applied in a turn, not just to slow the car, but to create weight transfer to the front wheels giving additional traction to help steer. As you know, it's a delicate balancing act. PTV does not slow the car or create weight transfer so it doesn't interfere with nor does it enhance trail braking.

Someone who has PTV+ may or may not be able to trail brake, but either way it has nothing to do with PTV+.

 

This is probably the most lucid comment - based in and on both practice & theory - that I've read in this entire debate.

Well done - and thank you!

John D.

 

So you are claiming that (a) applying a brake does not slow the car, and (b) this electronic gizmo is really there to help counteract the ridiculous amounts of understeer dialed into the car, right? I will definitely agree with (b). Not sure I agree with (a) however. Also please remember that trail braking does not just add bite to the front contact patches to aid turning, but also helps "loosen" the rear end, in order to help steer the car from the back end. In other words, it is used to adjust the attitude of the car from the rear, instead of adding more steering angle and tire scrub at the front. So it is all about rotation.

Personally, I am not sure I want some gizmo that applies rear brakes and diff based on a steering wheel sensor. Too damned complicated...definitely not a car to buy out of warranty. I mean, really...are GT3 drivers that bad that they need some complicated contraption just to help them turn? I sure hope not...

 

Guys. I know its getting boring waiting for the 05 March 991GT3/Turbo Official Press Release on the 991 GT3. The OP who mentioned PTV, 475 bhp etc has only made 3 posts in 3 years and looking at prior posts it would appear is not in a position of privilege to teach us anything new unless he can state his source. Fundamentally we are probably gassing on for nothing at this stage....

If anyone (with faster internet than me) can keep an eye for official leaked info and post it in the meantime would be much appreciated. Ive been following 991 GT3 scoops and spy photos for over 6 months religiously and I find it fascinating Porsche has managed to keep final specs so quite leading right up to the unveiling. Im expecting the curtain to drop any day and its testing my patience LOL!

 

The GT3 is a victim of it's own success, and I for one, hope sales of this 991 GT3 fall flat on it's face, if they indeed don't offer the most loyal part of their customer base with an option for a manual tranny.

 

Although applying slight brake pressure to the inside rear wheel might theoretically slow the car some tiny amount, it can't be detected by the driver. I have PTV+ on my Cayenne S and aside from excellent steering response entering a turn, nothing else is noticeable; certainly no slowing of the car. I don't have PTV in my Carrera and I can get it to rotate when I want it to; I wouldn't say "ridiculous amounts of understeer" are dialed into the car. Do you find that ridiculous amounts of understeer are dialed into the 997 GT3 and RS? Why would you assume that will be the case with the 991 GT3?

As I said in the previous post, trail braking is mainly about weight transfer; obviously if more weight is transfered to the front there will be less at the rear and yes, that does contribute to rotating the car. I guess we can wordsmith each other's posts, but that seems pointless. What is the point, is that PTV acts to enhance initial turn-in and steering response into low and medium speed turns where you aren't already braking. If, OTOH, when the driver brakes into a fast corner and is trail braking through the corner, there is no additional brake pressure applied to that inside rear wheel; PTV's yaw enhancing feature is overridden by what the driver is doing with the brakes.

Whether you want PTV or not is a completely different issue, but again, PTV does not intefere with or take the place of trail braking.

 

+1000 LOL

 

VR doing a fantastic job recruiting more students. I love it....

About the 991, I know there is tons of speculation, but in the end I foresee the car being a great car. Hopefully the manual is offered, as pdk only would be disappointing.

Every model has tweaks that take it further from a pure racer like the 996 GT3. But the gizmos will probably be long forgotten by the improvement of the front track width, and how much better front grip will be.

 

Ptv won't increase the total frictional load of the sum of all four tires.

Hence a good driver (with trail braking) will not need such a mechanism.

The discussion is really that simple.

I am sure someone with an engineering degree can better illustrate this. I just know how to do it but probably can't tell someone how to do it.

 

This isn't really worth all this discussion, but I'm stubborn so I'll try one more time. Do you trail brake into corners at low to medium speeds? Well that's where, and only where, the inside rear wheel braking feature of PTV works. It's designed to improve steering response at low and medium speeds, not at higher track or road speeds where you would be braking into and through the corner, ie using trail braking. PTV doesn't compensate for talent deficiencies, it's designed to improve steering response at moderate road speeds.