Corner bias brakes!???? - MR2 Owners Club Message Board
 
LinkBack Thread Tools
post #1 of 7 (permalink) Old December 1st, 2013, 10:50 Thread Starter
Registered User
 
Join Date: Jun 2006
Location: Cali, Atascadero/Fresno
Age: 55
Posts: 718
OldTrader Rating: (4)
Corner bias brakes!????

I've seen a lot of things in the many cars I've had in the past 30 years, but, I just came across a new thing. This does not have anything to do with an MR2, but possibly noteworthy in any forum. Corner bias brakes. Front left to rear right and front right to rear left. Is this a mistake from the assembly line or some engineered method of controlling the less enthused driving style? The car in question here is a 1987 AE82 (Corolla FX16 GTS). Anybody ever see this before? I drive the car rather hard and have never had any trouble braking in any situation. Is this some weird attempt at reducing the possibility of locking up front or rear axle? An early form of "antilock" brakes? I need to find out if this is normal for this car before I change things to what I have come to know as 'normal'.
sirdeuce is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old December 1st, 2013, 23:30
Registered User
 
Join Date: Mar 2004
Location: Arvada, CO
Age: 40
Posts: 4,905
OldTrader Rating: (11)
According to the factory service manual, the 350Z has diagonal brake circuits as well. It used to be the norm. Not sure why Nissan would do it on a sports car though.
scarecrowX is offline  
post #3 of 7 (permalink) Old December 4th, 2013, 06:28 Thread Starter
Registered User
 
Join Date: Jun 2006
Location: Cali, Atascadero/Fresno
Age: 55
Posts: 718
OldTrader Rating: (4)
Just hit me as odd. Should I keep it this way, or go with a front/rear bias?
sirdeuce is offline  
Sponsored Links
Advertisement
 
post #4 of 7 (permalink) Old December 5th, 2013, 23:13
Radical Two
click here to visit the sponsor page
 
Join Date: Dec 2004
Location: Carbondale CO
Posts: 11,255
OldTrader Rating: (11)
I am guessing it has nothing to do with bias and that front to rear bias will be balanced as it should when everything is working right. I would assume that it's just in case of a system failure.
If one line fails you have one wheel in front slowing you down and one wheel in the rear slowing you down.

If only your front brakes worked it could cause unpredictable understeer. Even worse if only your rear brakes worked it could cause extremely fast and unpredictable oversteer.

If each side was tied together then it could be a problem trying to brake in a corner where the brakes went out on the weighted side. It would also very heavily pull the car in the direction of the braking side.
yoshimitsuspeed is offline  
post #5 of 7 (permalink) Old December 7th, 2013, 09:47 Thread Starter
Registered User
 
Join Date: Jun 2006
Location: Cali, Atascadero/Fresno
Age: 55
Posts: 718
OldTrader Rating: (4)
That makes sense. Just my first introduction to such a system. Thanks for the input guys!
sirdeuce is offline  
post #6 of 7 (permalink) Old July 5th, 2014, 19:35
Registered User
 
Join Date: Oct 2009
Age: 28
Posts: 29
OldTrader Rating: (0)
Quote:
Originally Posted by sirdeuce View Post
I've seen a lot of things in the many cars I've had in the past 30 years, but, I just came across a new thing. This does not have anything to do with an MR2, but possibly noteworthy in any forum. Corner bias brakes. Front left to rear right and front right to rear left. Is this a mistake from the assembly line or some engineered method of controlling the less enthused driving style? The car in question here is a 1987 AE82 (Corolla FX16 GTS). Anybody ever see this before? I drive the car rather hard and have never had any trouble braking in any situation. Is this some weird attempt at reducing the possibility of locking up front or rear axle? An early form of "antilock" brakes? I need to find out if this is normal for this car before I change things to what I have come to know as 'normal'.
A lot of cheap FWD cars use diagonal dual-circuit brakes. Like others have said, its a safety concern in that if one circuit fails, you still have one front and one rear brake working in order to retain a greater level of stability under emergency braking (which you are probably already doing, or will be doing shortly if you have a brake circuit failure!). Being front heavy and prone to exceptional levels of pitch and roll, these econobox FWD cars were deemed to require this extra braking stability in case of circuit failure.
Medusa is offline  
post #7 of 7 (permalink) Old July 5th, 2014, 20:15
Registered User
 
Join Date: Oct 2009
Location: Lakeland, FL
Age: 42
Posts: 1,638
OldTrader Rating: (2)
Quote:
Originally Posted by Medusa View Post
A lot of cheap FWD cars use diagonal dual-circuit brakes. Like others have said, its a safety concern in that if one circuit fails, you still have one front and one rear brake working in order to retain a greater level of stability under emergency braking (which you are probably already doing, or will be doing shortly if you have a brake circuit failure!). Being front heavy and prone to exceptional levels of pitch and roll, these econobox FWD cars were deemed to require this extra braking stability in case of circuit failure.
^^^ This exactly.... The bias is still front to rear, just the circuit split is diagonal instead of front and rear. If you were to look at the Prop valve's from these cars, they are actually two valves in one.

In my opinion though, any front engine car should be like this even if they are RWD. Even cars with a near or at 50/50 weight distribution still are significantly front heavy under braking and run quite a bit more front bias as is from the brakes. Anyone how has ever had the front circuit fail on a front / rear split circuit setup on a front engine cars knows that its almost impossible to stop the car. I'm pretty sure this is the exact reason why Nissan runs a diagonal split on the 350Z as Karl (ScarecrowX) pointed out. I'm pretty sure they continued this config on the 370Z's also.
CJMR2T is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the MR2 Owners Club Message Board forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: (0 members)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome