We've all heard the suggestion to deactivate TCS when doing track driving in the dry, primarily to allow power to be applied in the corners, even under tire slippage/slide... this allows weight transfer to be kept in check, and keeps the rear end planted.
I was reading this article in my local PCA chapter magazine, and was wondering if folks have started seeing similar things with ABS.
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reproduced without permission from "Chicago Scene", PCA Chicago magazine, December 2003 edition...
The level of sophistication in our cars have achieved over the last several years is nothing short of miraculous. We now have cars that will shift exactly when they should, put power down to the ground to the wheel that needs it, and stops the wheel that has the best traction!
These are truly wonderful features of our new smarter vehicles. However, there are times when the driver needs the car to do something that might be contrary to the "intelligence" our vehicles now possess. This is going to be our topic today.
When a late model car with anti-lock brakes is being used for racing, the ABS system is unaware of whether the car is going backwards or forwards, it only knows that the wheels are spinning. The reason that this is an issue is as follows: the front brakes normally do most of the braking and are, therefore, much larger in size than the rear brakes. This is because, under braking, the weight of the car will shift towards the direction of travel, placing a much higher demand on the front brakes. Unfortunately, if the car gets completely out of control and ends up going backwards, this high braking demand is now placed on the forward-facing rear brakes, while unloading weight off the rearward-facing front brakes. Since the rear brakes are too small to do much stopping at all on their own, they are of very little use in this situtation. The larger front brakes which now have no weight on them, immediately lock up. The ABS sees this and, thinking the car is going forward, it releases the pressure on the front calipers, virtually eliminating any effect they might have had. What you are left with is a smart car which will not stop in a safe distance.
The remedy for this is to install a switch that can be easily activated to shut the ABS system off in such an emergency.
The highest priorities for such a switch are to be highly visible as well as easy to use in a panic situation. I have come up with a system that does both of these while still remaining simple and cost effective.
... proceeds on showing how this works on a 1993 Porsche 911-993 RS America, but it translates to most other Porsche models with ABS...
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Was wondering if any NSX folks have tried this ??
I was reading this article in my local PCA chapter magazine, and was wondering if folks have started seeing similar things with ABS.
##########
reproduced without permission from "Chicago Scene", PCA Chicago magazine, December 2003 edition...
The level of sophistication in our cars have achieved over the last several years is nothing short of miraculous. We now have cars that will shift exactly when they should, put power down to the ground to the wheel that needs it, and stops the wheel that has the best traction!
These are truly wonderful features of our new smarter vehicles. However, there are times when the driver needs the car to do something that might be contrary to the "intelligence" our vehicles now possess. This is going to be our topic today.
When a late model car with anti-lock brakes is being used for racing, the ABS system is unaware of whether the car is going backwards or forwards, it only knows that the wheels are spinning. The reason that this is an issue is as follows: the front brakes normally do most of the braking and are, therefore, much larger in size than the rear brakes. This is because, under braking, the weight of the car will shift towards the direction of travel, placing a much higher demand on the front brakes. Unfortunately, if the car gets completely out of control and ends up going backwards, this high braking demand is now placed on the forward-facing rear brakes, while unloading weight off the rearward-facing front brakes. Since the rear brakes are too small to do much stopping at all on their own, they are of very little use in this situtation. The larger front brakes which now have no weight on them, immediately lock up. The ABS sees this and, thinking the car is going forward, it releases the pressure on the front calipers, virtually eliminating any effect they might have had. What you are left with is a smart car which will not stop in a safe distance.
The remedy for this is to install a switch that can be easily activated to shut the ABS system off in such an emergency.
The highest priorities for such a switch are to be highly visible as well as easy to use in a panic situation. I have come up with a system that does both of these while still remaining simple and cost effective.
... proceeds on showing how this works on a 1993 Porsche 911-993 RS America, but it translates to most other Porsche models with ABS...
##############
Was wondering if any NSX folks have tried this ??
