15111111
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| posted on 8/8/09 at 04:55 PM |
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brake upgrade
running twin pot calipers on cortina front suspension without servo and would like to fit bigger calipers any suggestions on what would fit and/or do
the job cheers Keith
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flak monkey
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| posted on 8/8/09 at 05:01 PM |
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I have wilwood powerlites on my cortina uprights. Made quite a difference.
Go for Mintex M1144 pads in them though and avoid the smart pads as they are rubbish on the road.
Sera
http://www.motosera.com
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britishtrident
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| posted on 8/8/09 at 07:01 PM |
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Just fit a smaller bore master cylinder.
Cortina calipers are big you don't need bigger calipers just the right bore master cylinder to give the correct hydraulic line pressure to
allow the calipers piston to put enough force on the pads.
You need smaller bore master cylinder from a car with disc brakes but no servo ---- for example Mk1 Fiesta Van without servo.
[Edited on 8/8/09 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 8/8/09 at 07:06 PM |
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See ebay item 200362899423
LUCAS BRAKE MASTER CYLINDER PMC101(74066357)
FOR VEHICLES WITHOUT SERVO 17.5 MM DIA
New old stock
Not bad for 35 quid
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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15111111
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| posted on 10/8/09 at 06:03 PM |
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what effect does the master cylinder have on the pedal travel cheers
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flak monkey
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| posted on 10/8/09 at 09:18 PM |
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Smaller cylinder will give more travel but less effort.
Sera
http://www.motosera.com
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15111111
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| posted on 11/8/09 at 12:39 PM |
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IS THE AMOUNT OF ADDITIONAL TRAVEL SIGNIFICANT CAN IN BE QUANTIFIED BY % CHEERS
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britishtrident
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| posted on 14/8/09 at 06:41 PM |
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Pedal travel only becomes a problem with alloy multipot calipers because the calipers flex (and other reasons).
Westfield and Caterham both use 0.7" bore mastercylinders on the standard spec brakes.
The big problem with a Seven style car is getting hydraulic pressure anywhere near what the brakes calipers and pads are designed to operate at.
With short pedals and no servo the only way to get enough hydraulic pressure is to employ a smaller bore cylinder.
Pressure = force/area
So using a smaller bore cylinder increases the hydraulic pressure for the same force exerted by the drivers foot.
Road car brakes such are designed to operate with about 100bar pressure to give an emergency stop.
With the same donor mastercylinder a Seven style car with no servo and pedals half the leverage of the donor the same pedal presure will only
generate about 25bar.
If we allow for the Seven style car being half the weight of the donor the required brake pedal pressure required for a 0.9g emergency stop is still
twice that of the donor --- in human friendly old units say 100 pounds force
By changing to a smaller 0.7" dia mastercylinder the pedal force for an emergency stop is reduced to abot 70 pounds force which by modern
eurobox standards is still high but quite acceptable in a tradditional style sports car.
[Edited on 14/8/09 by britishtrident]
[Edited on 14/8/09 by britishtrident]
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