Why Late Model Cars Need Bigger Brakes (BA Falcon) - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Forum Ford Forum

» Auto Insurance
» Featured Product
» Wheel & Tire Center

Go Back   Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > The Garage - Tech Forums > Suspension | Wheels&Tires | Brakes
Register Home Forum Active Topics Photo Gallery Auto Loans Garage Mark Forums Read Auto Escrow

Suspension | Wheels&Tires | Brakes Sponsored by: Discount Tire Direct

FordForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 05-19-2003, 17:25   #1 (permalink)
Pursuit Reincarnation Dog
 
Aussie Pete's Avatar
 
Join Date: Apr 2001
Location: Melbourne VIC
Posts: 7,777
Read Why Late Model Cars Need Bigger Brakes (BA Falcon)

Some numbers to show you why late model cars need better brakes than those of earlier years. You have to remember that the brakes on cars today are handling much bigger levels of energy.

I have assumed the energy absorbed by the brakes is the entire amount of kinetic energy lost while slowing down (not quite true). Also, kinetic energy is one half mass times velocity squared.

Take a stop from 100km/h (27.8m/s):

1200kg car; E = 1/2 x 1200 x 27.8^2 = 463700 J
1800kg car; E = 1/2 x 1800 x 27.8^2 = 695550 J (1.5 times the energy)

However, consider that the cars today are generally capable of much higher speeds and accelerate better between two points and the issue becomes even worse:

1200kg car at 80km/h (22.2m/s); E = 295700 J
1800kg car at 100km/h; E = 695550 J (2.35 times the energy)

Now the big eye opener. Let's say you're on a winding road. You make repeated applications on the brakes to slow down for corners. In this case we assume the newer car accelerates better and handles better.

1200kg car cornering at 70km/h and accelerating to 100km/h

E = 1/2 x 1200 x 27.8^2 - 1/2 x 1200 x 19.5^2 = 463700 - 228150 = 235550 J

1800kg car cornering at 80km/h and accelerating to 120km/h

E = 1/2 x 1800 x 33.3^2 - 1/2 x 1800 x 22.2^2 = 998000 - 443550 = 554450 J (2.35 times the energy EVERY corner)

Now you see why the issue just gets bigger and bigger as cars get better and heavier.
__________________
BA'1.5' Pursuit 290
Lightning Strike / Reflective Orange Stripes

'General' Dog - AP's German Shepherd and Best Mate - 02Dec1998-15Dec2003.
'Pepper' Dog - General's and My Little German Shepherd Sweetie - 1996?-02Apr2006.

'Sako' Dog - My Beautiful and Pretty German Shepherd - 2001?-23Aug2006.
Aussie Pete is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-19-2003, 18:07   #2 (permalink)
Blue Blooded Ford Man
 
Join Date: Apr 2002
Location: Riverina, NSW. Falcon country
Age: 36
Posts: 1,619
You bored AP?
__________________
Marcos Ambrose - 2003 V8 Supercar CHAMPION
This could be the start of something big
KenOath is offline   Reply With Quote
Old 05-19-2003, 20:14   #3 (permalink)
Powered by HAD
 
AusXH's Avatar
 
Join Date: Jul 2001
Location: Central Coast NSW
Age: 32
Posts: 1,328
/me thinks he's trying to justify them huge arse Brembo's :s6:
__________________
PVTXR01
AusXH is offline   Reply With Quote
Old 05-19-2003, 23:58   #4 (permalink)
Pursuit Reincarnation Dog
 
Aussie Pete's Avatar
 
Join Date: Apr 2001
Location: Melbourne VIC
Posts: 7,777
Nah, some people were saying how older cars never seemed to have brake shudder etc.
__________________
BA'1.5' Pursuit 290
Lightning Strike / Reflective Orange Stripes

'General' Dog - AP's German Shepherd and Best Mate - 02Dec1998-15Dec2003.
'Pepper' Dog - General's and My Little German Shepherd Sweetie - 1996?-02Apr2006.

'Sako' Dog - My Beautiful and Pretty German Shepherd - 2001?-23Aug2006.
Aussie Pete is offline   Reply With Quote
Old 05-20-2003, 00:07   #5 (permalink)
We Love Greb Murpy
 
ford.boy's Avatar
 
Join Date: Jun 2002
Location: God's Country (Penrith)
Age: 28
Posts: 3,022


Ahh, yr ten science is good for something.
__________________
"When I joined the marines all they gave us was two sticks and a rock! And we had to share the rock between the whole platoon!"
-----------
H2 pwnz j00 foo.
ford.boy is offline   Reply With Quote
Old 05-20-2003, 03:11   #6 (permalink)
Registered User
 
FTEfan's Avatar
 
Join Date: Apr 2001
Location: At the babyshop
Age: 38
Posts: 1,112
Older cars would be hard pressed to generate enough heat in the brakes due to the speed and constant stopping.
__________________
Nothing on this earth beats holding your newborn child for the first time.
FTEfan is offline   Reply With Quote
Old 05-20-2003, 03:13   #7 (permalink)
BSR Twin System (tm)
 
smciner1's Avatar
 
Join Date: Aug 2001
Location: The TQE (tm) Plant.
Age: 40
Posts: 4,751
I have noticed that aerodynamics plays it part at highway speeds. Lift off the throttle at 100 km/h in my EF XR6 and it takes forever to loose some speed.

Do the same in my XB GT and it slows down a lot quicker.
so while improved aerodynamics helps late model cars in acceleration, fuel economy and wind noise, there is a (small) down side to it.

As an interesting thought to this, my EF XR6 and XB GT have very similar sized rotors, but the XB has vented rear disks standard, something that is a $6,000-00 option on a new GT. Just food for thought.

P.S. Thanks for the brush up on the Physics lesson AP.....
__________________
Falcon G.T. Club of Geelong Inc.
Deakin University Formula SAE Car PHANTOM ENGINEERING
LSUG (Leaf Spring Users Group) Twin System Engineer
Official BSR Website - www.bsrcorp.com
Poster of the 150,000th post!
BSR "DARTH HELMET (tm)"
Marcos Ambrose & SBR, 2003 & 2004 V8SUPERCAR Champions

****ADSLSUPERFASTP0RNPIPE (tm)****
smciner1 is offline   Reply With Quote
Old 05-20-2003, 03:35   #8 (permalink)
Registered User
 
Join Date: Jun 2002
Location: queensland
Posts: 1,134
Another issue is that most injected engines hold the revs up a little while coasting, and this means that you are on the brakes more to keep to the in town limit. I know a bloke who had two identical cars, except one was an auto and one was a manual. The auto used 3 times the brake pads of the manual.
__________________
If you're not driving a manual you're really just steering.
WBT56 is offline   Reply With Quote
Old 05-20-2003, 06:45   #9 (permalink)
Bourbon powered V8
 
JC-XR8's Avatar
 
Join Date: Sep 2002
Location: Canberra, Australia.
Posts: 4,787
That's because in a manual you change down through the gears (manually) which 'engages' engine braking. An auto changes down (automatically) as it hits certain speeds and has little or no engine braking effect. Unless, of course, you change the auto down manually to help with engine braking.
__________________
__________________________


AU1 XR8 Auto 147.9 rwkw (approx 215 fwkw)

AU2 Wagon HAD Auto
17s, Pacemakers, 3" Intake & Pod filter (The Family Hack)

Member of:
FPV-XR Club ACT
AUFalcon.com
ATPS (honorary)
JC-XR8 is offline   Reply With Quote
Old 05-21-2003, 02:48   #10 (permalink)
Registered User
 
Join Date: Jun 2002
Location: queensland
Posts: 1,134
It's more than that. The engine in either case does not return to base idle with no throttle- the idle stays high. Disconnect your VSS in an injected manual and go for a drive. The engine braking is greatly increased when the PCM thinks the car is stationary.
__________________
If you're not driving a manual you're really just steering.
WBT56 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > The Garage - Tech Forums > Suspension | Wheels&Tires | Brakes



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
BA Falcon Interior Reveal RPO83 Ford Worldwide News 5 09-16-2003 19:12
Falcon is ... Hobbes The Pub 26 08-05-2003 07:14
Another award Ford_Crazy The Pub 5 01-10-2003 04:13
BA article from Canberra Times Falchoon The Pub 8 09-27-2002 16:50
BA Falcon Engine Reveal RPO83 Ford Worldwide News 0 09-04-2002 08:27

Powered by vBadvanced CMPS v3.2.2

All times are GMT -7. The time now is 00:45.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.