On Wed, 11 Mar 1998, Aaron Johnson wrote:
> why wouldn't converting the rear to discs be good for a street car. I
> would think better braking would be good for any car.
Well, the bottom line is that in racing, you are at or near the "limit"
and everything helps you cut the line a little closer to the limit is a
little better. I would hope that driving on the street provides a very
large margin before you reach the limit... if not, let me know where you
drive so that I can give you a wide berth.
The common mistaken notion here is: if big is good, than bigger is more
better (double comparitive intended). The brakes on your TR6 are pretty
darn good for when the car was manufactured - I recall that TR6 brakes
were rated better than other of the sub- $3500 GT cars available at that
time: 914, Opel GT, 240Z, etc. Well maintained Triumph braking systems
are pretty darn good.
Carrying that notion even further, in racing you use pads that have a
very high coefficient of friction. But the tradeoff for stickier pads is
that they operate at much higher temperatures. They can operate for much
longer periods at those higher temps. A racing pad needs to come up to
temp before they will work. For your typical street driver, the pad would
not even come close to operating temps before you hit other cars and
objects around you... it is a very scary feeling the first time you tromp
your brakes to slow down so that you can avoid a wall that is directly in
front of you at say, over 100 MPH and _nothing happens_ until the pads
come up to temp... at that point - you can stop "real good". So, on your
"warmup lap" you're not just making the engine warm but the brakes too!
What I'm trying to say here is: yes the performance potential for racing
brakes is pretty amazing, but the tradeoff for that performance is that
they practically don't work at all in "normal" driving conditions.
To get an idea what I'm talking about, if you happen to have a catalog
from Racer Wholesale or Pegasus Racing, look at the temps that the brakes
operate at. There's a big difference between street compounds and the
racing compounds... like 400 degrees F.
The next challenge would be to balance the brake bias between the front
and the rear brakes. The stock MC provides something like 60 front 40
rear, this is probably too much rear bias and the result would be that it
would be way easy to lock the rear brakes before the fronts which will
present some interesting "driving challenges" to a "normal" driver. So,
you would need to plumb in a brake proportioning valve that is adjustable
or you would have to replace the single-unit-dual MC with two separate
MC's with a balance bar and/or adjustable proportioning valve.
Simple, eh?
And if it doesn't work correctly - how do you explain to the insurance
comapany?? Do you tell them that none of the parts that you are using
have D.O.T. certification???
I'm pretty sure that the article that I referred to earlier would work on
the street, but I'm at a loss as to which caliper they used and how they
got the rear emergency brake to work...
I'll figure it out and post it here, unless someone else remembers. Anyone?
regards,
rml
-------------------------------------------------------------------------------
Bob Lang Room N42-140Q | This space for rent.
Consultant MIT Computer Services |
Voice: (617)253-7438 FAX: (617)258-9535 |
-------------------------------------------------------------------------------
|