[DeTomaso] Working on dual MC conversion like Goran (Hemi Pantera) did, Anyone have ideas?

[Ken Green]

 Hi Richard,
I went through the numbers a long time ago and came up with 3/4 dia MCs.  The pedal ratio difference is something like you mentioned, 6.25 for the Wilwood pedals, and I think 4.8 for the Pantera pedals, so the difference is 1.3.  The area difference between 7/8 and 3/4 MCs . 1.2, nearly 1.3.  Seems like the added effort is just 8%?
But rotor diameter and pad material also come into this.

Ken

    On Sunday, March 22, 2020, 11:55:36 AM PDT, richard boschert via DeTomaso <detomaso at server.detomasolist.com> wrote:  
 
   Ken,
  I have the whole SAAC manual brake twin master cylinder conversion with
  the pedals.
  If you want to go  without power assist you MUST change the pedal
  ratio!The power booster makes a huge difference in pedal effort
  required.I cannot emphasize how much effort it will take to stop the
  car without power assistance.
  I have the wilwood 6.25 to 1 pedals.I dont remember the piston sizes on
  my wilwood superlite calipers,but they were not that large.I originally
  had twin 7/8 bore masters,but i dropped down to 3/4 bore masters,due to
  the pedal effort.Pedal travel is minimal.Effort is still high but
  manageable.It is really too high for 99 percent of the people in a
  street car.
  The online calculator i used took in all kinds of factors. Car weight
  as well as weight bias front to rear,center of gravity,rotor size
  ,caliper piston size,etc.For what its worth my car weighs 2700 lbs so
  it allowed a larger bore master as it assumes it will be easier to stop
  with less mass vs a stock panteras 3200 pounds.
  It came up with the 7/8 bore masters under high effort,race car and 3/4
  bore masters under moderate effort race/street.Im actually tempted to
  try 5/8 bore masters,as it is really a street car.
  I don't think you could go a small enough bore size in the master
  cylinder with the stock pedal ratio.I do not know what the stock
  pantera ratio is but most cars have a power assisted ratio around 5 to
  1.By the time you got the bore size down to a usable leg effort the
  pedal travel would be very far.Probably so far you could not lock up
  the brakes before the pedal hits the floor.They may not even make a
  brake master that small.
  The unexpected HUGE  plus of going with the SAAC setup or making your
  own plate with better ratio pedals vs the stock mounting plate and
  pedals is a drop in pedal effort for the clutch,and more room for your
  feet!
  Without a power booster in the way and wilwood pedals,the clutch master
  is now a normal straight pushrod versus the stock jackshaft offset
  master cylinder.I can also now wear normal shoes versus before i had to
  wear narrower driving shoes.The clutch is so much easier to use now and
  i had the effort reduction kit.To me this is as a big a selling point
  or more so than  the weight reduction which was my original reason for
  doing the conversion.
  Hope this helps make your decision on what to do.
  Richard
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-------------- next part --------------
   Hi Richard,
   I went through the numbers a long time ago and came up with 3/4 dia
   MCs.  The pedal ratio difference is something like you mentioned, 6.25
   for the Wilwood pedals, and I think 4.8 for the Pantera pedals, so the
   difference is 1.3.  The area difference between 7/8 and 3/4 MCs . 1.2,
   nearly 1.3.  Seems like the added effort is just 8%?
   But rotor diameter and pad material also come into this.
   Ken

   On Sunday, March 22, 2020, 11:55:36 AM PDT, richard boschert via
   DeTomaso <detomaso at server.detomasolist.com> wrote:
     Ken,
     I have the whole SAAC manual brake twin master cylinder conversion
   with
     the pedals.
     If you want to go  without power assist you MUST change the pedal
     ratio!The power booster makes a huge difference in pedal effort
     required.I cannot emphasize how much effort it will take to stop the
     car without power assistance.
     I have the wilwood 6.25 to 1 pedals.I dont remember the piston sizes
   on
     my wilwood superlite calipers,but they were not that large.I
   originally
     had twin 7/8 bore masters,but i dropped down to 3/4 bore masters,due
   to
     the pedal effort.Pedal travel is minimal.Effort is still high but
     manageable.It is really too high for 99 percent of the people in a
     street car.
     The online calculator i used took in all kinds of factors. Car weight
     as well as weight bias front to rear,center of gravity,rotor size
     ,caliper piston size,etc.For what its worth my car weighs 2700 lbs so
     it allowed a larger bore master as it assumes it will be easier to
   stop
     with less mass vs a stock panteras 3200 pounds.
     It came up with the 7/8 bore masters under high effort,race car and
   3/4
     bore masters under moderate effort race/street.Im actually tempted to
     try 5/8 bore masters,as it is really a street car.
     I don't think you could go a small enough bore size in the master
     cylinder with the stock pedal ratio.I do not know what the stock
     pantera ratio is but most cars have a power assisted ratio around 5
   to
     1.By the time you got the bore size down to a usable leg effort the
     pedal travel would be very far.Probably so far you could not lock up
     the brakes before the pedal hits the floor.They may not even make a
     brake master that small.
     The unexpected HUGE  plus of going with the SAAC setup or making your
     own plate with better ratio pedals vs the stock mounting plate and
     pedals is a drop in pedal effort for the clutch,and more room for
   your
     feet!
     Without a power booster in the way and wilwood pedals,the clutch
   master
     is now a normal straight pushrod versus the stock jackshaft offset
     master cylinder.I can also now wear normal shoes versus before i had
   to
     wear narrower driving shoes.The clutch is so much easier to use now
   and
     i had the effort reduction kit.To me this is as a big a selling point
     or more so than  the weight reduction which was my original reason
   for
     doing the conversion.
     Hope this helps make your decision on what to do.
     Richard
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