I seem to recall someone saying that they dont put VDC on auto's.. is that true? Do they just have TCS? Any idea why? Thanks!

 

I have an auto and I only have TCS and no VDC

 

Yup; no VDC on auto. I have no idea why.

 

This might help a little as an explination:

VDC is an advanced Vehicle Control System. Compared with current AWD, ABS, TCS systems, this new system enables the vehicle to be handled at the limits of adhesion during cornering, acceleration and braking with greatly improved control, providing safer, smoother driving under all conditions.

For example, you may enter a corner at what you think is the correct speed, but then realize halfway round that your speed is excessive for the road surface. This forces you to overcompensate and lose traction.
Excessive speed on slippery road surfaces can also lead to the car spinning out or even overshooting a corner.

VDC reduces the possibility of such overreactions, assisting the driver to maintain control and avoid accidents. The major difference between VDC and the AWD+ABS+TCS systems is the motion element being controlled. VDC offers 2-dimensional control as opposed to the 1-dimensional control provided by AWD+ABS+TCS. The AWD+ABS+TCS system senses the vehicles speed and acceleration in a straight line only, and uses these data to control braking and driving forces in order to prevent loss of traction.

By contrast, the new VDC system provides 2-dimensional control by also sensing the transversal movement of the vehicle and its yaw (rotation around the perpendicular axis).

It uses these data to predict the vehicle's direction in 2 dimensions and to control it within safe limits. The VDC system recognizes the course a driver wishes to take from the steering wheel angle and vehicle speed. It detects the current driving conditions from the wheel speed sensors, longitudinal and transversal G sensors and the yaw velocity sensor, and simultaneously estimates the coefficient of friction (potential loss of traction) of the road surface. It uses this information to predict the actual direction of the vehicle, and minimizes the difference between the desired and predicted course by controlling the driving and braking forces. When a potentially unstable situation is predicted because the desired course and the cars actual course differ, the braking and driving forces are controlled to regain stability.

Vehicle speed is also limited if necessary by reducing engine output and torque.

 

Ok, So why does'nt the auto have VDC?

 

I'm not an expert on this but from doing a little research this is what I understand it to be.

Because an automatic trans is already controlled by the computer (shifting) it doesn't need to be controlled is two dimensions, the computer can automatically "downshift as needed and reduce speed". A Manual trans on the other hand rely's on the driver to downshift hence the need for the car to be controlled in two dimensions by the VDC to eliviate the problem of over compensation in a turn.

 

doesn't the g come with vdc?!?! that's weird why they would leave it off the z and on the g.

 

I also asked this question awhile back https://my350z.com/forum/showthread....ghlight=leslie ,the last poster mentioned, that the 35th AT had it. and I think the G was mentioned also.

 

I'm just speculating but maybe the auto doesn't come with VDC to keep the cost down.

The Z in both AT and MT have plenty of driving nanny acronyms to help keep the car on it's intended path or to recover manually from an unfavorable situation even without VDC. On top of that, the 5AT isn't like most standard or sequential autos, the 5AT is driver and enviromental adaptable. If you are in auto-mode or if TCS gets activated the transmission is constantly monitoring and adjusting. The 5AT does have sensors that monitor the condition and handling of the car and it adjusts itself to those conditions. What it doesn't do once you've exceed the threshold of what the computer considers a safe yaw angle is attempt to correct problem on its own. It will instead assist the driver to manuallly recover. If TCS is controlling the 5AT, it can override the gearing, shift point, the amount of throttle cut or add, throttle tip-in and torque output. I think TCS on the 5AT also controls the brakes on the drive wheels. Except for throttle cut/add I don't think TCS on the 6MT controls anything else. VDC on the 6MT would use the independent brake controls to correct over/understeer and rely on the Brake LSD and Mechanical LSD to assist in torque delivery to the drive wheels. It would be nice to have the option of automatic yaw correction but, the 5AT already has some aids to prevent, control and recover from excessive yaw built into the 5AT design and the other driving nannys. Nissan probably just thought the cost of adding VDC was too much for what you got.

As far as the G35 goes, they most likely added it because of marketing. Most of the cars that the G35 competes against have full stability control. If they left stability control off of the G35, people that aren't familiar with stability control or the 5AT would think it was a major negative when it reality it's not that big of a difference. In this case, the perceived value of adding VDC was worth the extra cost to Infiniti.

This is just my guess.