Re: Disabling EDL (r6supafly)
quote:[HR][/HR]The ABS system monitors front wheel speed for differance under 20 mph it applies the brake on the faster (spinning) wheel.
This is pure speculation but if you install an ATB diff it will probably eliminate the need for EDL.[HR][/HR]
Not entirely. A TBD (ATB is Quaife's own term), is a torque multiplier, not a locking diff.
The multiplier is about 3 to 1 and it depends entirely on available traction. If the low
traction side can take 30 ft-lbs of torque before it slips, then a TBD will send up to 90 ft-lbs to the
higher traction side, for 120 ft-lbs of torque to the ground with no slippage. If you apply more torque
than that, the low traction tire will start to spin, but it takes longer for it to happen in
normal conditions. When the traction imbalance is very low (dry pavement where both sides
are nearly equal) both tires will either hook up fully, or spin at the same speed.
However, if the low traction side takes 0 ft-lbs of torque before it slips (shear patch of ice)
then 3 times 0 is still 0 and neither side gets any torque, just like an open diff. Most
people don't realize that. It's why off road 4x4 vehicles (jeeps, trucks etc) don't use TBDs
as they may, at times lift 1 or even 2 tires (opposite corners) coimpletely off the ground.
That makes for 0 applicable torque at those tires, and a TBD will be of no use (unless you use a braking trick).
I verified this a few days ago quite by accident when I parked on a slight uphill grade near the curb
and water had frozen in the gutter. My right tire was on ice, my left tire on pavement.
I went to drive away and my right tire spun freely and the car went nowhere at first.
A "locking" diff would have pulled away, but it has other downsides for performance driving.
In the zero traction instance, the EDL will still kick in and slow the spinning tire
but unlike the stock open diff, it'll work 3 times as effectively. The braking itself becomes
the resistive torque on the low traction side, and the TBD will give you 3 times that
much to the high traction side (open diff is 1 to 1). The TBD is way stronger too,
so you're not going to break it, if the EDL does activate.
Practically speaking, I find that the EDL activates very very seldom with my
Peloquin installed, because the zero traction situation is rare, and even moderate
traction will allow the diff to apply a lot of torque to the ground.
As for disabling EDL. We put together a mod to do this on the Mk3's.
So far I don't know of anyone who's attempted it with a MkIV, but it's
not hard, it is reversable, and I'd *love* it if someone could test it
out for me. If it succesfully disables the EDL on a drive by wire
MkIV, it may also disable the ASR without tripping the ASR light. That'd be a nice bonus.
On the other hand, the car may also think you're applying the brakes
all the time (the mod fools the ABS computer into thinking you're braking
instead of accelerating), and cut the fly by wire throttle. It depends
on whether the ECU gets its own signal wire to control that annoying "feature"
or uses the same ABS signal wire that this mod uses.
If anyone wants to test, this please email me and we can talk about it.
I'll update the page and give credit to anyone who's willing to help
me out on this.
[Modified by Daemon42, 6:24 PM 2-14-2002]