Dual Master cylinder setup

[cplucker1]

whats the general opinion about converting a tandem bosted setup to a balance bar and dual cylinders ? specifically on and EP BMW Z3 ? I have always raced IT and made do with the stock ish setup

Worthwhile ?

Thanks

 

[Joe Boruch]

I have an FP Miata still with OEM boosted brakes and one with balance bar and dual cylinders. The dual cylinder set-up certainly takes more pedal force, but has more consistent braking than the boosted brakes. I cannot comment on lap times yet, since I have not driven the dual cylinder car on the same tracks as the boosted car yet.

 

[harvey]

I converted mine when I built it and with stock calipers it was NOT so good. I went to Wilwood brake kit on the front and it was better then did a rear upgrade as well and now they feel great.

 

[cplucker1]

I was thinking of keeping the stock calipers for the lack of weight penalty, was just trying to decide on the direction for the pedals.

 

[harvey]

I honestly found the most improvement with calipers but in your case that may very well might be the case.

 

[Bill H.]

You need to consider the brakes as a system - you should not just change one component and expect it to perform well. You will want to look at the sizes of everything and compare. I have a spreadsheet that helps me look at this to see the impact to the whole system.



This was an evaluation of moving from the Stock setup (with some assumed values for the booster contribution) to a non-boosted set with balance bar (set to even split) and maintaining the same stock calipers. The master cylinder size for the latter examination was based on 1) what I had in house and 2) an attempt to balance output pressure with the pedal travel. As you can see, in order to get the same brake torque output at the front wheel, it will take at least 2X the input force to get their (and work would need to be done to balance with the rears).

I'm happy to share the spreadsheet if you would like. As with most spreadsheets, I understand it and would add some additional breadcrumbs to (hopefully) help you understand it as well.

 

[Bob Hess]

Great info Bill. What you have laid out is pretty close to what we've come up with for our cars. We use the Tilton system and have run stock calipers, MGB calipers up front and drums and Wilwoods out back with a proportioning valve in the middle. Always had good brakes with the Wilwoods as they really do settle down the rear end on rough braking.

Bob