Race Car Tech Discuss anything related to road racing and auto X.

Wilwood pedal assembly

Old 12-13-07, 04:58 PM
  #1  
Full Member
5 Year Member
Thread Starter
 
Join Date: Oct 2007
Location: Toronto
Posts: 111
Likes: 0
Received 0 Likes on 0 Posts
Wilwood pedal assembly

I'm ordering Wilwood's reverse swing pedal assembly for my FC race car, and was looking for some feedback on what some of you fellow racers are using.

By some rough calculations I'm leaning towards the 5.1:1 pedal ratio, 3/4" front master and 1" rear master cylinder bore sizing. This is for the stock TII brakes, and an approx. 2600lb race weight. This gives me line pressures of 350psi front and 260psi rear.

Pedal feel is driver preference, however I'd like to compare what I think will work for me, to what some of you are running.

Thanks,
Andrew.
Andoru is offline  
Old 12-14-07, 01:56 PM
  #2  
GSL-SE PRO
iTrader: (2)
 
JIMMY54's Avatar
 
Join Date: Aug 2001
Location: MISSISSAUGA, ONT. CAN
Posts: 2,515
Likes: 0
Received 0 Likes on 0 Posts
Sounds about right for your car....

My first gen has t2 calipers with the same size front m/c, but I have t2 calipers in the rear aswell.....

If I recall my pedal ratio is 6:1.....
JIMMY54 is offline  
Old 12-14-07, 05:33 PM
  #3  
Rotary Enthusiast
10 Year Member
 
Eggie's Avatar
 
Join Date: Jan 2002
Location: 15143
Posts: 859
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Andoru View Post
This gives me line pressures of 350psi front and 260psi rear.
Is that enough to stop the car?
Eggie is offline  
Old 12-16-07, 01:28 PM
  #4  
Rotary Enthusiast
10 Year Member
 
Join Date: Apr 2001
Location: North Hollywood, Ca USA
Posts: 1,289
Likes: 0
Received 0 Likes on 0 Posts
I am using 3/4" front and 7/8" for the rears. I have also tried it reversed. smaller diameter gives longer stroke and softer(less input power) pedal. larger diameter gives shorter stroke and firmer(more input pressure required) pedal. I have seen people use the 5/8" diameter for the fronts as well.
tims is offline  
Old 12-16-07, 03:52 PM
  #5  
Full Member
5 Year Member
Thread Starter
 
Join Date: Oct 2007
Location: Toronto
Posts: 111
Likes: 0
Received 0 Likes on 0 Posts
Thanks for the input guys.

Originally Posted by tims View Post
I am using 3/4" front and 7/8" for the rears. I have also tried it reversed. smaller diameter gives longer stroke and softer(less input power) pedal. larger diameter gives shorter stroke and firmer(more input pressure required) pedal. I have seen people use the 5/8" diameter for the fronts as well.
Yeah, the bigger the bore the shorter the stroke, the more muscle that's needed to obtain the same line pressure as a smaller bore.

What pedal ratio are you running tims?

Thanks,
Andrew.
Andoru is offline  
Old 12-16-07, 05:10 PM
  #6  
Rotary Enthusiast
10 Year Member
 
Eggie's Avatar
 
Join Date: Jan 2002
Location: 15143
Posts: 859
Likes: 0
Received 0 Likes on 0 Posts
And what calipers?
Eggie is offline  
Old 12-17-07, 11:20 AM
  #7  
****** of disaster
10 Year Member
iTrader: (1)
 
thetech's Avatar
 
Join Date: Aug 2001
Location: Santa Monica, CA
Posts: 1,115
Likes: 0
Received 0 Likes on 0 Posts
I am using 5/8" front and 3/4" rear with the 5.1:1.

Have to play with the balance bar adjuster a little to get it right, but in general no problems.
thetech is offline  
Old 12-17-07, 10:12 PM
  #8  
Rotary Enthusiast
10 Year Member
 
Join Date: Apr 2001
Location: North Hollywood, Ca USA
Posts: 1,289
Likes: 0
Received 0 Likes on 0 Posts
Eggie,
It really doesn't matter. I have used that setup on the stock FC calipers and my Wilwood bilet supelite 6 calipers

Andoru,
I am using the wilwood reverse mount pedal assembly.
tims is offline  
Old 12-19-07, 09:03 PM
  #9  
Rotary Enthusiast
10 Year Member
 
Eggie's Avatar
 
Join Date: Jan 2002
Location: 15143
Posts: 859
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by tims View Post
It really doesn't matter.
The name on the caliper may not matter, but the piston sizes make one heck of a difference.

I've been a bit too cryptic in this thread.

After doing some calculations, I highly doubt that Mazda calipers will provide enough braking at ~300psi. The FD's proportioning valve doesn't even kick in until 570psi (per FSM P-19).

Is my math way off?
Eggie is offline  
Old 12-19-07, 11:29 PM
  #10  
Full Member
5 Year Member
Thread Starter
 
Join Date: Oct 2007
Location: Toronto
Posts: 111
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Eggie View Post
The name on the caliper may not matter, but the piston sizes make one heck of a difference.

I've been a bit too cryptic in this thread.

After doing some calculations, I highly doubt that Mazda calipers will provide enough braking at ~300psi. The FD's proportioning valve doesn't even kick in until 570psi (per FSM P-19).

Is my math way off?
Your math is probably fine, I must have been drunk when I typed 350psi. Its 461psi front with a 3/4" master and 260psi rear with a 1" master. This is with a 5.1:1 pedal ratio and 80 pounds of force on the pedal by the driver. I calculated 400psi as the required line pressure according to all the required variables for my car (piston diameter, dynamic weight etc.).

If you want the exact math layed out, stop techs website has a very well written article laying out the calculation of master cylinder sizing.

My biggest dilemma is should I get the 5.1:1 or 6.25:1 pedal ratio offered by Wilwood. Because when it comes down to it, I can calculate all I like. Real world application out weights my calculations. I may find it too hard for me to press the pedal with the 5.1:1 ratio. 461psi may also not be enough, requiring me to press harder to achieve a higher pressure.

Anyway, good eye on catching me in my bluff

Thanks,
Andrew.

Last edited by Andoru; 12-19-07 at 11:40 PM.
Andoru is offline  
Old 12-20-07, 12:03 AM
  #11  
Rotary Enthusiast
10 Year Member
 
Eggie's Avatar
 
Join Date: Jan 2002
Location: 15143
Posts: 859
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Andoru View Post
Its 461psi front with a 3/4" master and 260psi rear with a 1" master. This is with a 5.1:1 pedal ratio and 80 pounds of force on the pedal by the driver.
I agree.

Originally Posted by Andoru View Post
I calculated 400psi as the required line pressure according to all the required variables for my car (piston diameter, dynamic weight etc.).
That's where we differ. My spreadsheet is set up for FDs, but I figure the 4-piston FC setup should be close. Continuing from 460/260psi, I get about .5g braking with .5u pads.

PM me your email address, and I'll send a copy of the sheet.
Eggie is offline  
Old 12-20-07, 12:58 AM
  #12  
Rotary Enthusiast
5 Year Member
iTrader: (1)
 
Join Date: Apr 2007
Location: SAN JOSE
Posts: 1,155
Likes: 0
Received 0 Likes on 0 Posts
i have a dual master swing pedal fs, let me know, pm me



didnt mean to thread jack
drftwerks is offline  
Old 12-23-07, 12:34 PM
  #13  
Full Member
5 Year Member
Thread Starter
 
Join Date: Oct 2007
Location: Toronto
Posts: 111
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Eggie View Post
I agree.

That's where we differ. My spreadsheet is set up for FDs, but I figure the 4-piston FC setup should be close. Continuing from 460/260psi, I get about .5g braking with .5u pads.

PM me your email address, and I'll send a copy of the sheet.
For some reason, the board will not allow me to send pm's because of my post count. Send me a pm with your email address and I'll email you my address. Don't want to post it here in fear of spam.

I appreciate the input you've given.

Andrew.
Andoru is offline  
Old 12-23-07, 12:53 PM
  #14  
Rotary Enthusiast
10 Year Member
 
Join Date: Apr 2001
Location: North Hollywood, Ca USA
Posts: 1,289
Likes: 0
Received 0 Likes on 0 Posts
everybody's math seems correct, but in the real world it doesn't matter. the larger the piston size of the caliper does require more volume of brake fluid. This will then give you a longer stroke on the M/C, and if you used a larger diameter M/C it would give you a shorter stroke. In the real world I have used all types of combinations with the same results. If you want a softer(less pressure needed) pedal use the smaller diameter M/C. Most people will find that there is very little pressure needed for the rear brakes so the larger M/C will give you more adjustment on the balance bar. I started by calculating what I "should" use and found the best combo for my particular style by trial and error. I do have a collection of used M/C's though. I personally would start with (2) 3/4" M/C's.
tims is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
LongDuck
1st Generation Specific (1979-1985)
12
10-07-15 08:12 PM


Thread Tools
Search this Thread
Quick Reply: Wilwood pedal assembly


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: