I've seen the following write ups, but what really do they mean, does the '04 have a similar system to all the other dynamic stability programs out there? Anyone know how this really works? Do the car's breaks literally work on individual wheels to keep the car on a straight path? Here's one of the article exceprts:

"Of course the shock tuning is revised and the four disc brakes get new pad material, a new master cylinder, and the ABS system now features "yaw control logic" which is, well, controlled and logical."

 

I've never heard anything about the '04 cars having any sort of stability or yaw control. Anti-lock brakes, sure, but that's it.

 

Here's a link to a little more info from this site:

http://www.vtec.net/articles/view-article?...6&page_number=4

 

Ah! I get it now. Basically, if you happen to have the left tires on pavement and right right tires on grass, the ABS is smart enough to tell the difference in traction and react accordingly.

But there is no system like Porsche's stability control function that will apply individual brakes to keep the car from spinning out if you got into a corner too hot, or the like.

 

ok, so it isn't an active stability control system per se, its more of a smart ABS system with lateral biasing depending on surface conditions under braking

 

Hmmmm, sounds a bit like a marketing ploy!? To throw the "Yaw" in there seems to suggest it literally keeps the car on the straight and narrow. I suppose whatever system it uses monitors the yaw and adjusts each wheel to counteract a spin? Or is that more of an "active" type of yaw sensign mechanism. Where's a Honda engineer when you need one!?

 

My interpretation from this short article is that it isn't a stability system. A stability system constantly montitors during all phases of driving and uses power and braking distribution to keep the car on the road. This system seems to be limited strictly to braking. I don't think the s2000 has a yaw sensor, an accelerometer, or anything to detect yaw. I think it simply senses traction under braking and applies the required forces to each wheel in order to maintain a controlled braking maneouvre.

 

it has a yaw sensor built into the ABS sensor.

only works in conjuction with the ABS sensor.

.....or so i'm told.

 

So it only works when ABS is engaged? Or can it work randomly under accelaration?

 

It only works when ABS is active - therefore it is not a true yaw control. It is simply updating of the ABS to take into account different wheel/surface traction to keep the car straight.

To put it this way, the job of ABS is to prevent the wheels from locking up.

If one wheel is on a grippy surface and one on a slippery surface, applying different *braking forces* to each wheel to prevent it locking up is still the same function as ABS. If that helps to keep the car straight then so be it, but it has no sensor to measure the angle of the wheels or the angle that the vehicle is travelling in.

True yaw control aims to improve a vehicle's cornering and acceleration performance (not just braking).
This is achieved by utilising a *torque transfer* differential which is controlled by various sensors and an electronic control unit (ECU) to enable a difference in *torque* to go to each of the rear wheels.
For example, turning a fast corner, if you apply more torque to the outside rear wheel (compared to inside wheels)this will help the car turn into the corner and not understeer.