Just wanted to hear about some of your setups and how the pedal feel is. Looking to shorten the pedal throw, take all the slop or initial pedal movement before the brakes start to bite and increase the feel through the pedal at impending lockup.

I have an 89 GTU with the original booster/mc but I swapped over to the s4 T2 calipers/rotors. My brakes are bled and the car technically brakes perfectly fine with more than enough power to lock up the tires but the pedal feels like a toyota camry or an american suv.


I've been looking at the 929 setup and still may go that way. Honestly I dont need amazing race car brakes and I'm not saying I want porsche brakes but I have driven a couple porsches and I'm looking for that stiff short throw feel to the brakes. I am even thinking of goign with a 929 1" mc and NO booster which would create a VERY stiff pedal, but its prob way too stiff.


Things I plan to do include carbotec xp8 pads and bracing the MC
Dont know if its possible to acheive what I'm looking for.

Just exploring options in case I missed something. I hate working with brake fluid so I'de like to do this just once.

Thanks

 

one of the cars im working on doesn't have a vacuum source going to the booster yet, and it sucks just driving it around in a parking lot...i can't imagine trying to brake with speed.

 

There's a great thread on here that i cant seem to find about a guy who experimented swapping out several different MC's from different cars, just to see how a different diameter MC would effect the brake feel / response. Im in a hurry, but its on here... IIRC he had the greatest success with a Subaru MC.

 

Its called "The holy grail Part II" I read through it a few times. Want to hear about other setups if there is any. I think I did a good amount of searching just made this thread in case I missed something

 

You can adjust the rod length from pedal to the mc under the dash on the pedal assembly to stiffen up the feel. The FSM or chiltons/haynes manual will show you how to adjust it. I remember I had to do it when I first got my car because the pedal feel sucked. Try this before you start swapping parts!

 

(1) Manual brakes will not shorten the throw at all. With out the help of the booster you will need a SMALLER diameter MC with a longer throw, The rod on the petal is to adjust slop but you can not use it to stiffen up the brakes.
(2) I had the 4 lug set up on mine and did the swap over to the 5lug 4 piston and had no change in feel. The S5 may be softer than S4? but i don't know.
(3)If you want to get more feel try SS lines and check for leaks or bad MC or leaking line, they should not be overly soft. If you KNOW there is no air in the lines 100%, you swap out to SS lines and its still not firm enough get the 929 MC and keep you're booster. Again no booster you need smaller MC with longer throw, If you get a larger mc AND run no booster you will push the pedal so hard you will leave you're seat and still run over 9000 kittens.
(4) look in the archive, its there, its easy, it works better than you think.


As I said, this is not manual breaks. Its just like steering, power rack with no power is a bitch, manual rack makes you think any one with power rack is a puss.

again. this has nothing to do with petal pressure, just free play. But having it proper will make them feel stiffer just due to the fact the more you push them the harder they are and now its starting to work earlier.

 

adjust the brake booster pushrod length

 

Shoot Z-Brown a PM on the v8rx7forum. He's done it and explained it in his build thread.

Good luck.

 

zbrown is the guy to ask.
We've spoken a few times and it's important to note that he didn't just ditch the booster and install the MC.
The MC was relocated to increase the pedal ratio, a feat he made seem easy but appears more complicated to me.

I made a dual MC, manual setup for my 240Z and loved the results.
I had first upgraded to 4-piston Toyota truck calipers in front (stock was two piston) and from drums in the rear to Volvo 2-piston calipers.
Later went with Outlaw 4-piston front calipers with larger diameter Acura rotors.

Since I didn't make a balance bar setup, I had to get the proportioning set by juggling MC sizes- math will only get you so close and there's a bit of "try it and see" at the end.
I'm guessing that car had the brake feel (not to mention performance) you're looking for but it took a lot more than just replacing the MC/booster to get there.

 

From what I have read, you need to keep the brakes adjusted for a small amount of initial "slop". Otherwise, when the braking system heats up under heavy use, it expands, takes up all the slop, the brakes start dragging, and you'll cook your calipers, rotors, and pads.