Master Cylinder sizes

[Brett James-McCall]

Can any of the technical gurus out there help me out. I need to work out the best master cylinder sizes to buy with my pedals.

The pedal is a dual cylinder floor mount with a ratio of 6:1. There will be no servos.

Front Caliper/discs/pads are: AP racing CP5040 using 315/28 discs and the CP3215D50 pad that has a 57.4cm2 area

Rear Caliper/disc/pads are: Wilwood Powerlite using a a 278/20 disc and 40cm2 area.

I will be running a standard GTD. Thanks

Brett

 

[Brian]

Brett, If you go to the Tilton web site, there is a service available for them to calculate the proper sizes for you. There is a form to fill out which asks for several car specifics and upon submittal and evaluation, a technician will get back to you with recommended sizes.

Brian

 

[Brett James-McCall]

Thanks Brian sent in. Anyone care to take any guesses to see if you come up with what Tilton suggest? I'll post what they send through when I get it back.

Brett

 

[Ian Anderson]

Brett

0.625 inch for the front and 0.7 for the rear

If the balance bar has enough movement 0.625 for both.

Unless Ford has a good offer Rally Design are the cheapest I found

I would think any bigger and you will not get the correct brake pedal to stopping ration for SVA

Ian

 

[Brett James-McCall]

Brian,
Just out of interest, how long do Tilton take to normally get back to you?

Brett

 

[Clayton]

Brett
What sizes are the pistons in both calipers and the radial height of the Wilwood pad ?

Clayton

 

[SteveB]

Brett

There was an interesting item in the GT40 Enthuiasts January 1997 issue by Dave Pushon. I think it is still on the club Technical pages.

Regards

Steve

 

[Clayton]

Hi Brett

With all the info you supplied and working on a 75lb pedal input, the closest master sizes were:
0.938” (15/16”) front
0.625” (5/8”) rear
With a 77lb pedal effort as a result.
To decrease the split between the masters you could decrease the front caliper piston sizes, increase the rear caliper piston sizes, increase the rear disc dia.

Now comes the important disclaimer, these are my results so please check with AP or Wilwood.

Clayton

 

[Brett James-McCall]

Well Tilton have only just replied:

Brett,

Looking at your information, we recommend a 7/8" front and a 3/4" rear
master cylinder.

Regards,

Ehren VanSchmus
Tilton Engineering
[email protected]
805/688-2353 X 131

 

[Dave Bilyk]

Brett,

in case it makes a difference for you I could not match the caliper and pad on the AP website.

Front Caliper/discs/pads are: AP racing CP5040 using 315/28 discs and the CP3215D50 pad that has a 57.4cm2 area

I found the CP5040 caliper linked to the CP3345D44 pad with 43.3cm2 area, and the CP3215D50 pad linked to the CP3307 caliper

Dave