brake proportioning, calculations, and rear brakes - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Suspension, Brakes, Drivetrain discuss the wondrous effects of boost and your miata...

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 02-22-2010, 05:01 PM   #1
Elite Member
Thread Starter
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default brake proportioning, calculations, and rear brakes

I finally wrote a spreadsheet to calculate brake proportioning.

Here are my main findings:

Upgrading to a front BBK

It appears that the following BBK setup will have very similar bias to a stock 2003 Sport without ABS, which is the pre-NC stock car with the most rear bias that uses a prop valve.

11" front with 4 wilwood calipers x 1.38" pistons
9.8" (standard 1.8) rear rotors with (2003) 1.375" pistons

The big rear rotors (9.8") with the 1.8 caliper (1.2" pistons) doesn't increase the rear bias as much as the above.

On adjustable prop valves

You can't get the same proper proportioning (over a range of tire/surface grip available) by keeping the rear 1.8 brakes with a front BBK, with just an adjustable prop valve. A prop valve will help fine tune a setup that's close; a prop valve with stock rear brakes and front BBK will enable you to get good rear bias at one set of tires/surface grip, but will require lots of adjustment for optimal braking at other grip conditions. A more optimal setup will be closer to perfect over variations of grip and will require minimal adjustment from a prop valve.

The rear 9.8" rotors with the 2003 calipers will give you too much rear bias and you will really need an adjustable prop valve to bring the rear bias down. This setup however, will give even better proportioning, especially in high grip conditions - i.e. dry with street tires to dry with race tires.

Questions

Now my first Q is -
has anyone experienced fade in the rear or otherwise measured temperatures, with the rear 9.8" rotors?

Is it a bolt-on affair? Are the rear pads the same between a 2003 and a 94~97?
JasonC SBB is offline   Reply With Quote
Old 02-23-2010, 01:46 AM   #2
Junior Member
 
Join Date: Apr 2008
Posts: 350
Total Cats: -2
Default

1.8 brakes use FMSI D636 rear pad.

Sport brakes use FMSI D891 (I think) rear pad. Bigger, maybe thicker.

Pads follow brackets, not sliders.

Haven't proven it all bolts up on a car yet, but I believe the mixing and matching of which you speak is mechanically compatible.
SolarYellow510 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM
Another Alternator thread ihiryu General Miata Chat 9 09-28-2015 11:22 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:42 AM.