Traction Control & Racing

[CSH-HQ]

><snip>
>
>What traction control is all about is reducing the power to the wheels,
>>or specific wheel, when the tire's adhesion ability is exceeded.  There
>>is a lot of potential ways to achieve this, the most common by the OEMs
>>is to chop ignition to one or more cylinders in a logical fashion,
>>reducing flywheel power.  This is good because while hard on the engine,

Not all ignition chops are that hard.  ie using prime numbers for cyl drops,
ie drop every 7th cyl fire, then 5th, etc.  At stage one works out to like 
18% HP drop, and is actually no rougher than a less than a dead ign wire.

>>it won't destroy it the same way as cutting fuel to an injector, and
>>leaning the hell out of the engine.  BOOM!  

Bzzzt, will no fuel, it ain't lean, cause there ain't no fire..

There are some who believe
>>applying brakes is a good form of traction control - bad - because it
>>would be very difficult for a vehicle to determine if its sliding
>>forward or sideways, and much to complex to make reliable and cheap,
>>which is the OEM goal.  Therefore, applying brakes automatically by an
>>ECM could result in a slight slide (driver fuckup) turning into a slide
>>off the road over a cliff, into the ocean (worse case).
>>
><snip>
>
>Traction control is actually about maximizing traction without upsetting the 
>stability of the vehicle.  The traction control system ideally allows just 
>enough tire slip to allow the tires to operate at the peak of the 
>longitudinal Mu slip curve (usually between 15 and 20 percent).  The reason 
>you shut off traction control for autocross, solo, ect. is that so you can 
>alter the handling balance with the throttle.  All cars including race cars 
>are set up to understeer, by using the throttle on a rear drive car you can 
>cut the available lateral grip on the rear tires and make the car oversteer.
>
>Brake traction control is generally used in higher powered vehicles to 
>quickly bring slip under control or to redistribute power in a split Mu 
>situation.  Lower priced vehicles typically have engine only traction 
>control systems because they are very cheap, a little engine code, some code 
>in the ABS control unit and hardware to communicate back and forth.  
>Traction control intervention will not cause a vehicle to go out of control. 
>  Try driving a traction control vehicle on ice and doing donuts; it won't 
>do them.

I can do that with a 98 Gran Marquis, with TC.

  You have to get the car spinning before you hit the throttle, 
>since traction control controls longitudinal slip it actually enhances 
>lateral grip.  The max lateral grip versus longitudinal slip curve is a 
>concave asymptotic curve with a peak of nearly one G at zero longitudinal 
>slip and a minimum of zero G at one hundred percent longitudinal slip.
>
>Try beating the stopping distance of ABS on dry pavement.

Big challenge, take all the dum shit outta the sytem, and they are good, 
it's the power booost, and on-off none moculated rap that people like that 
screw it up.  I redid the brakes on my 84 F-body to full manual, and it is 
like a new car. Well modulated, progrssive, with plenty of feed back.  
Besides most people freeze, and son't even turn the steering wheel when the 
ABS kicks, so ABS is usuallly useless to the average jerk driver.
Doc
>
>Rich V.
>
>
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