Hey guys, I'm working on my 5 lug conversion right now, I have everything I need except a master cylinder. I'm thinking about using a willwood or tilton unit with remote reservoirs and a balance adjuster mounted in the engine bay near the master cylinder for ease of install. With these units I would be removing the brake booster unit and just having manual brakes. My questions are what has been used with success before, what bore and stroke master do I need for the best balance of amount of force needed on the pedal to force generated at the calipers.

the car is an 88FC that I'm building and using as a track day car. I'm not doing any competitive racing so dont need to comply to any rules that may limit modifications.

Thanks in advance for your input.

-Kyle

 

I have an old 1st gen SA chassis with Tilton masters.
3/4" dia front master and 1" dia rear master work with my Wilwood calipers.

 

5/8" front
7/10" rear

With stock FC 4 pot calipers. I had to change the pedal ratio to get to the feel I wanted. It was too hard with the stock ratio, IIRC about 5:1 mine is around 6:1 now. I have some pics somewhere that show how I modified the stock pedal assembly to use a balance bar and two masters on the otherside of the firewall.

 

Wilwood master cylinders are fine.
I use 3/4 and 3/4.
I have seen 7/8 front and 3/4 rear. It depends on your caliper size.

I looked at various pedal boxes and decided to just modify the stock brake pedal.
This design has the balance bar on the inside on the fire wall and the cylinders on the outside...
I copied the idea then designed the parts.

Design photo attached.

DIY FD brake pedal box.
You need,
2 x 3/4 inch willwood master cylinders
1 x willwood adjustable brake balance bar
Remote cable
4 bolts and 4 nyloc nuts.

3 laser cut plates
2 pieces of laser cut tube
(I can supply these.)

1 x 1mm cut off disk and an angle grinder.
1 x steel mig welder
1 x alloy tig welder

Cut excess parts of old pedal box
Weld on new bits
Cut the mastercylinder hole in the wirewall a bit bigger so the new master cyliner boots fit through.
Mount new bits in car weld fire wall plate over the hole.
All done.

Interested? glen@rx7.net.nz

 

right now I am planing on puting it together with the stock 4 piston calipers, but in the future would probably upgrade.

FD I'm going to send you an email this week, thanks. The only thing I dont really have easy access to is a tig welder.

-Kyle

 

Can you send me pics of a left hand drive brake pedal assembly?
I want to see if it is different to a right hand drive one

 

wilwood makes good stuff along with Brembo, you would be better of bleeding your current system if you having problems and new SS lines

 

I am using t2 calipers front and rear, 3/4 and 7/8 wasn't working for me. I just recieved my new 5/8 for the front and the 3/4 will be used for the rear.

I was getting 450psi (under regular foot pressure... 1200 max under extreme) to the front with my 3/4 front before and I need to bring that way up. Hopefully the 5/8 master will do the trick.

Also my pedal ratio is the 6:1..... using tilon masters with wilwood balance bar.... tilton has more master cylinder size options than willwood.

In a first gen... pic of the masters



Pic of brake bias gauges

 

Going from a 3/4" master to a 5/8" master will up your pressure from 450 psi to 648 psi.

"Regular" foot pressure means nothing when you go from power brakes to manual brakes. You will have to push much harder on the pedal when you take the power brake booster away!!

 

Very true... But I do need the higher pressure, previous sized front MC wasn't cutting it. At work we've put together some cars with manual brakes and with proper sizing you couldn't tell. I'm tring to zero in on that.

But if you are correct with your pressure estimate then it should be were I want it.

I've installed the new master yesterday, I just go to bleed the system and try it out...

I'll post my new results when I got them.

 

Tilton tech support is very helpful, you can talk to them about what you're planning.

I'll second the bit about it being much stiffer with manual MCs, every time I drive my normal car after driving my race car I whomp on the brakes :o

If you're going to manual MCs its a good idea to get the remote balance beam adjuster **** and the lever style rear bias valve too... The **** is much easier than reaching under the dash with a wrench, and the lever is useful for very simple non-fiddly tweaking while actually out on the track in changing conditions.

 

I should have tried the tech support, back when I started this project, but everything is done now.

I do have the remote balance bar adjuster, and the rear proportioning valve with in reach. Full race car setup... I swapped in the 5/8 MC for the front and it's quite abit better. I find I still have to press the brakes harder than a street car but it's not too bad.

under moderate foot pressure the front MC hits about 600 psi, just alittle bit more and it shoots to 800psi.... And it stops nicely. Now I just need a more aggressive set of pads for the track.

 

What pads are you using?

 

hawk pads

 

'scuse my ignorance, but why would you need a prop valve for the rears if you have a balance bar?

 

The lever-style can be adjusted quickly without thinking about it for changing conditions during a race. Push the lever forward for more front bias, back for more rear.

 

The not thinking part is key. I ended up putting the reminder sticker for my bias set up next to my Aim dash in my line of sight. The **** is down next to the base of the shifter.

 

I have the **** style, The lever is the one to get for all you guys thinking about going this route.

I will possibly swap it out, as soon as I get a few other things out of the way.