In a message dated 8/7/2007 10:27:00 P.M. Pacific Daylight Time,
lrc@red4est.com writes:
I found that when I took my, at the time, stock, MGB to the track,
the stock braking system just did not hold up. My first step was
improved pads, Ferodo DS-11. These days there are even better ones, I
like the Porterfields.
Even the better pads were not sufficient, so I then cut about 6" out
of the valence between the frame rail and the tire. That allowed
enough air to get to the brakes that they will hold up at tracks like
Sears Point and Thunderhill.
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Larry, you can't say that a stock braking system is inadequate because you
can fade them in hard use - you have to give them a chance to work and that
includes adding some cooling if you intend to race.
Look at an XKE for instance. The rear brakes fade badly even with excellent
pads, and doubling the size of the caliper and pad doesn't really address the
problem. They simply need some cooling air up there (they are mounted
inboard under the trunk where it is VERY difficult to cool them).
If you are driving an MGB hard enough to fade Porterfield pads, either
change pad material or attend to some added cooling if that doesn't work.
You can make up a quickly swappable set up using headlight buckets with
screened covers and attachments at the back for plastic and wire dryer ducting
to
get some air down there. Make sure you attach the tubing properly near the
brakes as otherwise the tire will catch it and you'll look a right twit as
you trail yards of unwound wire and plastic behind you (don't ask me how I
know
this).
Many spoilers and air dams also have provision for a duct of some sort for
this purpose.
Interesting that you say you can fade the Porterfields. I have NEVER been
able to fade the old DS-11s - we had a local track that had a long straight
ending downhill, which resulted in closing speeds about 10 MPH greater than at
any other track on the West coast and I was never able to fade the Ferodos
even braking from close on 130 each lap. In fact I did manage to get the discs
hot enough that I melted the grease boots on the tie rod ends so it wasn't
that my brakes were running particularly cool.
And I can't believe that MGB brakes are that much inferior to MGA (although
the air flow will obviously be a bit different with the different bodywork)
as I pitted for a guy that ran a quick MGB (man after my own heart - ran a 3
main engine) in a 7 hour endurance race and never faded the DS-11s he used.
I use regular R4 Porterfields - what are you using?.
In any case, it seems to me that adding a bit of air is a much cheaper
solution to brakes that are too hot than spending $1400 on new brakes, but
that's
just me.....:-)
Bill
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