Pedal Box and Master Cylinders
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Pedal Box and Master Cylinders
Well MK II of my pedal box and master cylinder setup is under way, I have now changed to using 3 No. remote master cylinders on my modified mini pedal box, 0.625 for the clutch and a 0.625/0.75 front rear split. The box is back in and the cylinders are in place, had to adjust the pedal angle but apart from that its working nicely so far. Sorry no pics so far as I didn't have the camera, but heres one of the pedal box in modified form.
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Sun Feb 22, 2009 7:14 pm |
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minitici
Looking like a GTM
Joined: Sat Jul 26, 2008 9:45 am Posts: 189 Location: Scotland [GTMOC 1190] GTM: Cox/Coupe
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Re: Pedal Box and Master Cylinders
.625 sounds a bit small for the clutch. It needs to move a fair amount of fluid.
_________________ 1967 Cox GTM; 1970 GTM Coupe, Lancia GTM Spaceframe , 1997 Rossa Mk2 (Two is never enough!)
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Sun Feb 22, 2009 10:10 pm |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
I'm trying this as a starting point as with the heavy duty diaphram the clutch pedal is arfully stiff, if I need to go up one size I will.
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Mon Feb 23, 2009 11:32 am |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
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Fri Feb 27, 2009 9:58 pm |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
Right update on the system, clutch works perfectly, much much better than original, it is now easy to operate, but the brakes are still having teething issues. Can those who have knowledge of brakes please help me on this. I'm using 2 x 0.625 master cylinders one running the front the other the rear, the car has discs all round std 1275GT front and VW sliding caliper on the rear. I have a brake bias valve on the rear line. I have good pedal feel but I'm not getting enough pressure to apply the brakes fully. I thought by using the 0.625 cylinders this would allow me to overcome a heavy pedal but I seem to have a heavy pedal still and not very effective pressure.
Please give your opinions
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Sat Feb 28, 2009 4:49 pm |
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West
Admin, and Coupe Nutter
Joined: Fri Sep 14, 2007 10:34 pm Posts: 1762 Location: In the workshop GTM: Cox/Coupe
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Re: Pedal Box and Master Cylinders
What is your current pedal ratio
my gut feeling its not large enough, i too run 2 x 0.625 cylinders and i run a 5.2:1 pedal ratio from memory and that is acceptable
WEST
_________________ IF wile e coyote had a GTM he would have one with Nitrous too! watch out road runner! The First GTM into the 11s then the 10s, PB 10.87 @ 125.5 Mph on A048 tyres, and fully road legal at Santa Pod
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Sat Feb 28, 2009 5:58 pm |
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gtmdriver
On the Road
Joined: Tue Oct 30, 2007 8:44 am Posts: 632 Location: Chester le Street
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Re: Pedal Box and Master Cylinders
I didn't use a bias valve in the rear system. Is it normal to do so?
_________________ GRP rules!
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Sun Mar 01, 2009 9:12 am |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
West,
do you know the coupe std pedal dimensions, if you know those I can work out mine as I know how much I've changed from the original. Otherwise i will look today.
Do you have any pics of use of how you were able to get the required ratio.
Gtmdriver,
The bias valve is only there as a compensator to equal out the braking force to the rear so that they don't lock up before the fronts do. Also a advantage in the wet as you can load more bias to the rear to avoid locking up the fronts.
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Sun Mar 01, 2009 10:29 am |
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West
Admin, and Coupe Nutter
Joined: Fri Sep 14, 2007 10:34 pm Posts: 1762 Location: In the workshop GTM: Cox/Coupe
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Re: Pedal Box and Master Cylinders
Well with my old system with the mini modified pedal gave a pedal ratio of about 3:1 from memory, but that was a long time ago, i have been running my fully adjustable pedal box for almost 5 years now Only pic i have with me, but bassically the pedal pivot is as high as possible, to give a nice arc of travel and to maximise the ratio.
Attachments:
Pedal box yum carbon.JPG [ 50.46 KiB | Viewed 13159 times ]
_________________ IF wile e coyote had a GTM he would have one with Nitrous too! watch out road runner! The First GTM into the 11s then the 10s, PB 10.87 @ 125.5 Mph on A048 tyres, and fully road legal at Santa Pod
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Sun Mar 01, 2009 11:23 am |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
Yeah I've just measured mine and its in the order of 3.5:1 or 4:1 so no good for the tandem system, back to the drawing board. I'm thinking if I shorten the length between the fulcrum point and the cylinder attachment point by about 20mm I should be able to achieve 5.8:1 ratio. I believe I can do this especially with the remote system, I just now need to fine another pedal box that I can chop up and play with. This will mean a lot of refabrication of the pedal box though. Anything can be done with time.
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Sun Mar 01, 2009 12:46 pm |
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West
Admin, and Coupe Nutter
Joined: Fri Sep 14, 2007 10:34 pm Posts: 1762 Location: In the workshop GTM: Cox/Coupe
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Re: Pedal Box and Master Cylinders
Andy wrote: .......... I'm thinking if I shorten the length between the fulcrum point and the cylinder attachment point by about 20mm I should be able to achieve 5.8:1 ratio......... You need to be carefull that you keep the pedal/cylinders arcs in raising rate as if you go into falling rate it will feel very odd when you drive it. WEST
_________________ IF wile e coyote had a GTM he would have one with Nitrous too! watch out road runner! The First GTM into the 11s then the 10s, PB 10.87 @ 125.5 Mph on A048 tyres, and fully road legal at Santa Pod
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Sun Mar 01, 2009 1:36 pm |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
West, i have just found this on the net, what do you think, it would still need modification but I think in whole its a better package. CLASSIC MINI ADJUSTABLE BRAKE CAB CLUTCH PEDAL BOX 311 Ebay Item number: 200269519840 http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... otohosting
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Sun Mar 01, 2009 2:00 pm |
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the other Tim
The Terrible Tims
Joined: Sat Sep 29, 2007 12:23 pm Posts: 487 Location: suffolk GTM: Cox/Coupe
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Re: Pedal Box and Master Cylinders
Andy, There's also this http://www.kad-uk.com/minibraking.htmWhich also reminds me to give Tim Rowe a nudge
_________________ I'm not a complete idiot, parts of me are missing!!!!!
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Sun Mar 01, 2009 3:02 pm |
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Andy
Ready for SVA
Joined: Thu Nov 15, 2007 10:22 pm Posts: 363 Location: Ireland
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Re: Pedal Box and Master Cylinders
Yeah I've seen those before but not sure about its workings on a coupe, anyone got any thoughts on the KAD system. Not sure if the pedal ratios would be suitable with the KAD system as the coupe pedals are shorter and offset different. I'm going to play around with another mini pedal box, offset the adapter plate/attachment plate by around 20mm and then shorten the master cylinder attachement point by the same amount, this should allow the cylinder to move on the same arc but effectivley give me a 5.5:1 or better ratio. I want to persevere with this potion as I have the clutch pedal working perfectly with an easy force action not like before when it was a monster of a pedal. The other auction item looked like a good piece of kit but again I was dubious of the length of the pedal and the effect on the system (i.e. pedal ratio) if I shortened it.
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Sun Mar 01, 2009 6:52 pm |
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West
Admin, and Coupe Nutter
Joined: Fri Sep 14, 2007 10:34 pm Posts: 1762 Location: In the workshop GTM: Cox/Coupe
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Re: Pedal Box and Master Cylinders
Yep the KAD one as far as i can make out does not alter the ratio, altho through a cunning bit of redesign im sure it can be, and i have seen something simular fitted to a gtm it may have even been the kad item.
that pedal box you found looks interesting certainly would be worth an email for some dimensions, prehaps even a dimensioned drawing!
WEST
_________________ IF wile e coyote had a GTM he would have one with Nitrous too! watch out road runner! The First GTM into the 11s then the 10s, PB 10.87 @ 125.5 Mph on A048 tyres, and fully road legal at Santa Pod
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Sun Mar 01, 2009 11:01 pm |
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