[Fot] dual circuit brakes on a tr4

[Kas Kastner]

In 1969 I made up a dual brake system for the Competition Department TR-250. 
The booster chamber unit was removed. I used two 5/8" master cylinders and 
made my own pedal arm  that had a 4.5 to 1 ratio. It worked so well we kept 
it on the TR-6 that replaced the TR-250 body and when I saw that car in 2002 
at Mid-Ohio it still had the same pedal box I had made so long ago.  It was 
the way that I recognized the car as being my old racer.
----- Original Message ----- 
From: "Steven Preiss" <spreiss at verizon.net>
To: "Greg Solow" <gregmogdoc at surfnetusa.com>; "Joe Curry" 
<spitlist at cox.net>; <WEmery7451 at aol.com>; <markvaden at gmail.com>; 
<fot at autox.team.net>
Sent: Thursday, November 01, 2007 9:18 PM
Subject: Re: [Fot] dual circuit brakes on a tr4


> Is it correct to assume that a single cylinder, dual piston master as
> commonly found in modern braking systems would similarly require increased
> pedal pressure? In any case, I'm not sure I understand the restrction on
> fitting such a master, sourced inexpensively from a Toyota for instance,
> when the rules seem to allow expensive custom systems from aftermarket
> manufacturers that were never available to racers "back in the day". Am I
> being naive? What also of employing brake boosters? They were available as
> early as 1969 or thereabouts if I'm not mistaken, and though obviously not
> used on the earlier cars have been fitted to them for street applications
> with good results for some time.
> Steve P
> ----- Original Message ----- 
> From: "Greg Solow" <gregmogdoc at surfnetusa.com>
> To: "Joe Curry" <spitlist at cox.net>; <WEmery7451 at aol.com>;
> <markvaden at gmail.com>; <fot at autox.team.net>
> Sent: Saturday, November 03, 2007 6:06 AM
> Subject: Re: [Fot] dual circuit brakes on a tr4
>
>
>> The pedal effort required to operate the brakes is determined by the area
> of
>> the master cylinder or cylinders in relation to the area of the wheel
>> cylinders or caliper pistons. So using two master cylinders of the same
> size
>> gives WAY more piston area and the effort required will go up 
>> damatically.
>> When we put a Tilton balance bar setup on Bill Fink's Morgan SLR a number
> of
>> years ago we used two 5/8" masters and that still required more pedal
> effort
>> than the stock single 3/4" master that a Morgan uses. I understand that
>> someone, possibly Wilwood now makes 9/16" Master cylinders. They would be
>> closer in total piston area the a singe 3/4 or .700" master.
>>
>>             Greg Solow
>> ----- Original Message ----- 
>> From: "Joe Curry" <spitlist at cox.net>
>> To: <WEmery7451 at aol.com>; <markvaden at gmail.com>; <fot at autox.team.net>
>> Sent: Friday, November 02, 2007 10:24 AM
>> Subject: Re: [Fot] dual circuit brakes on a tr4
>>
>>
>> >I noticed the same thing when I installed  two Single circuit master
>> > cylinders and the Tilton balance bar on my Spit.  The petal is much
> harder
>> > and requires more effort to brake than before.  I previously had a dual
>> > circuit GT6 master cylinder installed and wanted to gain a bit more
>> > control
>> > on the front/rear balance.
>> >
>> > Joe C.
>> >
>> > ----- Original Message ----- 
>> > From: <WEmery7451 at aol.com>
>> > To: <markvaden at gmail.com>; <fot at autox.team.net>
>> > Sent: Friday, November 02, 2007 9:34 AM
>> > Subject: Re: [Fot] dual circuit brakes on a tr4
>> >> I was surprised the first time out on the track with this system.  I
> had
>> > to
>> >> push the brake peddle a lot harder to get the same effect.
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