Don Marshall wrote:
> Amici... Its a rainy Sunday here in north Florida so it seems like a good
> time to ask for advice from experienced racers.
>
..........................
>
> My real question is, hassle and cost aside, is there any significant
> difference, for vintage racing purposes, between 1) a split MC/balance bar
> setup with adjustable brake balancing capability and 2) a stock TR6 MC? I
> know that many of the vintage TR4s are using the TR6 MC and they seem to
> stop OK, which would indicate that the balance of the stock MC is OK for
> racing. But if the hassle and cost is about equal, is there an advantage
> to keeping the separate MCs and adding the balance bar that would make a
> difference to the average racer or should I just do whichever turns out to
> be easier? Have I overlooked another option?
>
> Thanks..
> Don
> TR4A #11
I ran a survey on the list a couple of years ago and found that most successful
racers were using the dual Tilton / balance bar setup. Currently in the central
part of the country there are at least four TR's with the TR6 and booster
setup.
I can only give you the results of my personal experience, and maybe they will
help you make a difference.
I ran the TR6 cylinder and booster, with the TR6 pedal assembly for five years.
never any trouble except for one failure of the used booster. When that failed,
the car was pretty hard to stop, but it was stoppable. I would not want a pedal
that hard if I was running an endurance race.
The problem I had with that setup was the lack of ability to modulate the
brakes with precision. Maybe it was just me, but there seemed to be a critical
point somewhere in the pedal travel where the booster came in too strong and
I'd lock up brakes much to the amusement of my tires, which flat spotted just
to punish me.
In addition, we always felt that we needed a little more rear brakes, which of
course is a function of cylinder sizes, but we never played around with it. One
indication of this was that the rear brake shoues lasted five years but the
front pads would last only two events. This gave us lots of practice working on
the front brakes but we never got a quick as the guys at the Sebring 12 Hour.
Wow.
I'm rebuilding the car after a wreck so I have a chance to do it all over
again. I'm installing dual Tiltons and the balance bar. To do this properly I
reconfigured the firewall to give the pedals a vertical mounting surface. In
addition, when I did the math for the pedal lever ratio, I found that the stock
pedal length / pivot point gave a ratio that was too high, which I think would
make the pedal effort too high, and which is probably why the brakes felt as
they did when the booster failed. To alleviate this problem I moved the pivot
point up on the pedals, shooting for a 6:1 ratio which according to Ted
Schumacher is ideal. I didn't quite make 6:1 but I got close. This turns out to
be a balancing act between pedal travel and ratio, becsause the Tiltons are
limited to a 1.1" travel at the cylinder.
>From my Formula Ford experience years ago (which had absolutely the most
wonderful brakes on the planet) the adjustable balance bar is useful for
initial setup but is seldom if ever used after that.
Now, the only problem with you making any decision based on all the above is
that I have not run the car yet with the new setup, so I don't know how it
works. However, those three Tiltons standing proud on the firewall sure do look
cool.
--
uncle jack
Like I said, "Life isn't long enough for me to do another ground-up
restoration". Well, thank goodness, it is.
|