TD in DC

Sorry if this has been gone through before, but my search didn't work well.

What are the primary differences in technology between:

(1) the generation of PSM used on the 2000-2004 996;
(2) the generation of TC used on the 997 GT3; and
(3) the generation of TC used on the 1999 996?

What happens when you turn the TC off on the 997 GT3?

Thanks,

TD

MJones

PSM & TC are entirely different

PSM:
When PSM's computer determines that the car is dynamically "misbehaving," it intervenes to keep the 911 on course. When it senses understeer - the "plow" of a vehicle's nose toward the outside of a curve - PSM subtly and almost instantly applies the brake on the inside rear wheel, yawing the car in the direction of the curve. In the event of oversteering, when the rear of the car "fishtails" toward the outside of a bend (a condition that, if unchecked, will almost certainly result in a spin), PSM gently brakes the outside front wheel to restore neutral handling.
Input to the PSM control unit comes from sensors, which measure the speed of each wheel, yaw rate, lateral acceleration, and steering angle. Several times per second, the computer compares the driver's intentions with the response of the car, making corrections as needed to hold a turn, steady a stop, or temper wheelspin on acceleration.

TC:
A system that provides driving stability during acceleration.

Functional Principal of Traction Control
When the drive wheels are spinning the ABD function first brakes the wheel with the higher slip.
If both wheels are spinning ASR is applied wthin fractions of a second.
The prpose of Anti-Slip Regulation is to prevent excess wheel slip on the drive wheels in order to increase cornering traction at the rear axle. The ASR function is active during acceleration across the entire speed range. With this function, intervention in the engine management system decreases the engines power by lowering the engines torque. This is achieved by closing the throtle and reducing the ignition angle. When ASR is activated, the relevant light lights up in the instrument cluster. This yellow information light indicates that the traction limit has been reached.

Bottom line:
PSM will try to save you
TC, your on your own

Hope this helps....

MetalSolid

For the first time ever, the new 911 GT3 is equipped with Traction Control (TC) as standard. Derived from the Carrera GT, this proven technology combines Automatic Brake Differential (ABD), Anti-Slip Regulation (ASR) and Engine Drag Torque Control (MSR) functionality.

Like PSM, "TC" utilizes the brakes (ASR & MSR) to maintain stability...

TD in DC

OK, forgive me if I am being dense here, but is the TC acting like a form of electronic LSD (albeit more complicated).

Bob Rouleau

TD - PSM is a multifunction system. It uses E-Gas, Yaw Control, Stability Control and Traction Control. It's based on an intertial sensor(yaw), wheel speed sensors and a steering angle sensor.

Yaw contol uses steering wheel angle and a yaw sensor to determine if the slip angle (tire slip angle) is out of range. If so, it will kick your foot off the brake pedal (hard!) and apply the brake to a wheel to cure oversteer or understeer. You may have felt this on a 996 while tril braking. On the 996 Yaw control is always on and cannot be turned off with the PSM switch.

Traction control was accurately described above, it detects yaw angles and excess wheel-spin and corrects it. It is a component of PSM and in the 997 GT3 it is controlled by a switch. In the 996, TC goes off when you turn off PSM.

PSM - stabiliy management uses the various sensors to detect a loss of control and can apply a brake to a wheel, or reduce power or both to attempt to prevent a los of control.

You might consider PSM to be the superset of yaw and traction control. I believe the main difference between ABD and Traction Control is that ABD on earlier cars only worked at low speeds whereas TC works at any speed.

ABD is a poor man's limited slip. It prevents a spinning wheel from grabbing all the power by applying the brake to that wheel. Cars with PSM cannot have an aggressive LSD like the 996 GT2/3 because the mechanical locking differential interferes with PSM and yaw control. The 997 GT3 has a less aggressive LSD than the 996 and I suspect TC is the reason.

Does this help?

Best,

TD in DC

Yes it does. I am hearing the siren song of the 997 GT3 and GT3RS and I am trying to understand more why they put TC on it, and whether this is an improvement over the 996 GT3 and if so, why.

Why would you ever turn TC off?

P.S. I am trying to resist and instead buy an old school carrera . . . but hearing all the rave reviews is making it difficult. . .

P.S. x2. Is the TC on the 997 GT3 basically the same as the TC on the 99 996?

PogueMoHone

The Traction control is Carrera GT technology in the GT3.

You just would not believe the extent of the changes in the new GT3 until you read it.

It just goes on and on.

TD in DC

Colm, you are the main person to blame you SOB.

The only thing holding me back is that all of my friends have Carreras. The whole point of going to DEs, IMHO, is to play around with your friends. My fear is that if I get a 997 GT3, I will have nobody to play with.

turbo187

you have nothing to fear. Once they see the car, they will have to have one as well!

QuickSix

I'm not sure if this is true but I heard that the '99 996 has TC because it has a throttle cable. When Porsche went to an electronic throttle, PSM was able to control the throttle electronically versus mechanically.

khaug

The only thing holding me back is that all of my friends have Carreras. The whole point of going to DEs, IMHO, is to play around with your friends. My fear is that if I get a 997 GT3, I will have nobody to play with.

So, your choices are: (A) GT3 @ $110K or so, or (B) A certain brown Carrera for $18K <G>.

BTW, the Brown Car is now buried in winter storage for the duration!

Nordschleife

ABD is a cheap technology, do not get stuck in snow with it, you may even set your pads alight. In ABD equipped cars, I find brake temperatures can rise alarmingly. You may need uprated rear brakes, with greater thermal capacity, to cope. I wonder if there is a speed cut out on the 997; other ABD equipped cars I have driven had a maximum speed above which ABD was inoperative.
The most desirable choice is traction control with an electronically controlled differential, this way traction control, stability management and the differential do not trip up over each other, if this sounds familiar, it should do.

R+C

TD in DC

Trust me, I have not forgotten . . . and I will be making a decision relatively soon . . .

P.S. Karl was my very first DE instructor and the man responsible for getting me addicted to the track. I don't know whether to love him or hate him for that. I do know my wife's answer

JasonAndreas

The max speed is 100Km/hr on every other model Porsche so it shouldn't be that much different for the 997?

Bob Rouleau

TD - the Traction Control system on the 997GT3 and RS is based on the CGT mechanism. It is different in that it works with a real limited slip as opposed to ABD which Nord correctly dissed above. The LSD on the 997 GT3 has less lock up that the 996 and I suspect TC is the reason.

Why turn it off? Well if you want to enter drifting competitions you would want it off. Same for lurid slides at corner exit, slow but great for crowd appeal. I won't know til I try mine on a track next spring, but if TC works they way I hope it will, corner exits will be faster because the system responds faster that I can to excess slip. See F1 cars which all use it.

Regarding the 99 996, the C4S had PSM available, I believe it was the first model with it as an option. E-Gas is required for PSM since the stability control and traction control need the ability to reduce throttle to recover control. This cannot be done with a straight mechanical connection.

Has anyone figured out how engine drag torque control (std on the 997 GT3s) works? I suspect it prevents a loss of control if you lift suddenly and inadvertently transfer weight to the front. Jason?

Best,


Best,