DIY Traction Control?

Chuck Tomlinson tomlinsc at ix.netcom.com
Sat Oct 5 18:17:56 GMT 1996


> From: MaxBoost at aol.com
> 
> How about a DIY traction control system?
> 
> Relatively simple comparison of wheel speeds (most cars have abs these days,
> so parts are readily avail).  Wire into the injector ground circuit back to
> the ecm and drop cylinders as needed.  Use a pic processor and some drivers
> to interupt the ground circuit.  
> 
> Also need an on off switch on the dash as well as a pot to adjust the
> percentage of slip allowed.  (got to have the switch so you can turn it off
> and roast the tires :)

IMHO, engine-based DIY TCS much more feasible than DIY ABS.  My only 
(theoretical) reservation about dropping cylinders is that it may introduce 
some crank-killing harmonics.  I'd probably want to use a stronger crank than 
normal, and a viscous torsional damper.  

A really sweet setup could use a secondary throttle as well.  This motor-
driven throttle would be normally wide open (spring loaded).  I'd probably 
limit the travel of the sec'y throttle to prevent it from going too close 
to fully closed.  That way you still have a little power if your TCS goes 
nuts on you when you're pulling out into traffic =8-0

Anyway, I can offer a few simple tips for anyone who wants to try TCS.  

1) Use the undriven wheel on each side as the speed reference for the 
   driven wheel on that side.  The system will be less likely to 
   trigger in tight turns.  

2) Consider retarding the spark (if you can) as a fine-tuning torque 
   control: smoother operation in marginal traction conditions.  

3) If you have an electronic auto trans, consider commanding an upshift 
   if TCS is active too long.  This is not good for racing, but it's 
   smoother on slippery roads.  

4) Consider varying your control gains based on the acceleration of the 
   reference wheels.  If TCS triggers and the ref accel is low, then 
   you're on a slippery surface.  More conservative speed control may 
   be appropriate on slick roads.

5) Also, if the system triggers and ref accel is negative, you're 
   probably in ABS and your TCS routine should _not_ take action.

--
Chuck Tomlinson <tomlinsc at ix.netcom.com>




More information about the Diy_efi mailing list