There's also this option:

Fab9Tuning Brake Booster Delete/Tuck Kit

 

as much as i respect fab9's work, and they have some very nice stuff. you really want to increase the pedal ratio to somewhere in the 5.75:1. stock pedal ratio is 4:1

with a single master cylinder unit you need to pinch off or kill the rear line pressure with a prop valve to balance the system. when we are talking about manual brakes it's hard enough to generate line pressure. that and dual MC's provide a safety catch of two separate cells. so if you have a failure in one, the other is still able to function to slow the vehicle.

 

Yeah, they claim that increasing the pedal ratio on their setup isn't that much side load on the master. But that's sketchy, something like that should have virtually no side load.

 

i agree, side load on masters is a bad idea. it just means that eventually it will fail (like all things mechanical). hopefully you can catch it when it does.

 

Anything that has the word "tuck" in the product description is not a track part.

--Ian

 

You can find electric vac assist pumps, like around $60. I think they even have pressure switches, so they won't run all the time. Wonder if that would make things more linear?

 

bingo.

 

it has mass. i'll need to weigh all the brackets, steel pedals, linkages and stuff. it adds up and replacing it all with a cast aluminum housing that under 5 lbs.

 

I haven't read all 707 posts on this thread, but I'm having issues with Russell front brake lines touching the wheels when they are at full lock. Any suggestions? I tried adjusting the banjo to different positions with no luck

 

Thanks for the quick and awesome replies!

I have considered a vacuum canister, and have even looked into tee-ing off of my crank case vacuum pump (no, it is not Swedish! Racing Vacuum Pumps from GZ Motorsports ). At the end of the day, I want things simple and reliable. Less weight, fewer points of failure. I'd happily get rid of the vacuum pump, but it is very effective and necessary in my setup. Anyway...


Pedals
I am open to suggestions on pedals.

I'm looking at Tilton 600 series, aluminum, firewall mount.

Wilwood's Tru-Bar pedals seem interesting, but my gut tells me to stick with Tilton.
Tilton 900 look awesome, but the price. Wow!

As things stand, I'd go with the Tilton 600's, which have an adjustable pedal ratio from 5.0 - 6.2:1

Caliper Piston Sizes & Quantity:
I'm using Wilwood DynaPro Radial Mount calipers, front, four 1.38" pistons each, fixed mount.
Rear calipers are stock 1.8 single 1.25" piston, floating.

Rotor Sizes:
Front 11.75" Curved vane.
Rear 10.9", solid (OEM "Sport Brake")

Swept Area:
According to my rough math:
11.75" Diameter Rotor, 1.625" pad height, swept area of each side of each front rotor is 52.75 square inches.
10.9" Diameter Rotor, 1.125" pad height, swept area of each side of each rear rotor is 34.55 square inches.

So what would be your recommendation for f/r master sizes?

Thanks,

Will

 

Vacuum Reservoir 47076 - Dorman (47076)

 

I really wish it worked like that. I can say from experience when you forgot to bleed the rear circuit on a dual master car it doesnt really stop. The balance bar just flops over to the side with no resistance and then the pedal assembly binds up and you get nearly no front brake pressure and then you nearly run someone over puttering out of the paddock.

 

Which pedal assembly were you using?

 

Wilwood High-Performance Disc Brakes - Pedals - Floor Mount Brake Pedal

 

Have a look at my thread on deleting the brake booster. I'm running dual masters modified into the stock pedal with an adjustable balance bar.

My setup is similar to yours with 200whp N/A and basically my brake booster would fluctuate under brakes due to the massive cams. The logs showed the brake pressure changing as I blipped down through the gears and you could feel it in the pedal.

Changing to the dual masters, even with the stock pedal ratio, fixed the fluctuations under brakes, plus the adjustable balance bar adjustable on the track is awesome.

I was driving home from my last event and I realised I hadn't thought about brakes the entire weekend. The feel is consistent and controllable and it's a very easy mod.

Do you get any oil pressure dips under brakes?

 

The balance bar I'm using has stops. I tested it on the road with air in the rear line and the fronts could be locked. I'm not sure on the brand but it has little wings either side of the pivot ball that limits the angle on the bar to 20 degrees or so... enough that it bottoms out before the pedal hits the floor.

It does make bleeding the brakes a little harder though as you are limited by the other side. You have to bleed both front and rear together.

 

with the caliper pistons being as tiny as it is i see a requirement for a .625 =5/8 master cylinders. on front and rear. this will net a requirement for the MC's travel to be 11mm your pedal will need to travel 40.25mm. make sure you have enough room.

 

Maybe one day when I get better at driving I will do some of these things, but you guys definitely know your stuff. Reading lots of goodies here.

I was mentally sold on PFC pads until I realized they didn't come in my Sport size, needed something better for the season but couldn't spend on BBK, and figured a lot of people run Carbotech stuff so it should be fine for me, a novice driver, albeit in a powerful car on sticky tires, but also not on a very brake intensive track. I got Centric blank rotors, G-Loc R12/10 pads, and Singular 2.5" ducts to keep things cool. Something I could afford to do, because a BBK with new PFC pads, and ducts would have cost me 2x more than the above, and that's before rear brakes.

I figure I'll probably wear the brakes out until I learn to drive fast enough to really need another set, at which point I can do something different.

Or should I really pinch my pennies, return the front end of the brakes I just ordered, get a Wilwood BBK, and spring for the PFC pads up front?

 

Awesome, thank you!

What would be the benefit of larger pistons/piston area? I am not opposed to changing what I have now, and they do need a rebuild. I stuck with the similar-to-OEM size to go along with the factory master cylinder and booster. Now that those are coming out, I am not tied to those piston sizes.

Also, what are your thoughts on those Afco calipers? Have you test fit any 15x8/15x9" aluminum wheels over them? I posted a video a while back of the Wilwoods with a micrometer attached, while stepping on the pedal. There was a measurable amount of flex, I was impressed, but not in a good way.


Madjak, Yes, I had oiling issues. Revving to 8500RPM, dropped oil pressure to 7-8psi coming out of heavy braking zones. The pressure drop while braking did not concern me, but that it was there of 1-2 after being back on the throttle did. I use a Maruha baffle and 2 quart accusump. Still see a small drop, but only to 30 psi or so, and recovery is faster. You can search some threads here and see some of my old posts. This is a bit OT - feel free to post in a different thread or hit me up with a PM, if interested.

Likewise, there is a post somewhere where I showed logged data of brake booster vacuum pressure under braking. Looked like a zig-zag chart, lots of fluctuation.

 

all of the little calipers are mehhh in performance. i have the afcos and they really went cheap on the bolts. surprisingly a lot of good engineering is in the caliper but they get a big fat F in materials used. they really need a bridge bolt if your going to use them in Motorsports. I got them i drilled out the pin, installed a bridge bolt, i'm about to call up apr and get some studs for them.