Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 01-22-2012, 11:45 AM   #1
Registered User
 
Join Date: May 2011
Location: Miami florida
Posts: 1,591
ABS engaging during hard braking

During hard braking, from about 80 mph on a straight flat road, the right front wheel's ABS in engaging. I am trying to brake as hard as I can, but I don't just use the brake pedal as an on off switch. I get on the brakes and after the weight is transfered to the front, I really mash the pedal and thats when the ABS engages. Very good tires, pressures correct, pads/rotors all in good shape.

Maybe I'm just reaching the limits of my brakes?
__________________
Current car

2000 Boxster 2.7l red/black

Previous cars

1973 Opel Manta
1969(?) Fiat 850 Convertible
1979 Lancia Beta Coupe
1981 Alfa Romeo GTV 6
1985 Alfa Romeo Graduate
1985 Porsche 944
1989 Porsche 944
1981 Triumph TR7
1989 (?) Alfa Romeo Milano
1993 Saab 9000
san rensho is offline   Reply With Quote
Old 01-22-2012, 11:51 AM   #2
Registered User
 
ppbon's Avatar
 
Join Date: Nov 2005
Location: Florida
Posts: 529
That is...

Quote:
Originally Posted by san rensho View Post
During hard braking, from about 80 mph on a straight flat road, the right front wheel's ABS in engaging. I am trying to brake as hard as I can, but I don't just use the brake pedal as an on off switch. I get on the brakes and after the weight is transfered to the front, I really mash the pedal and thats when the ABS engages. Very good tires, pressures correct, pads/rotors all in good shape.

Maybe I'm just reaching the limits of my brakes?
... very normal.
Happy Boxstering,
Pedro
__________________
Racecar spelled backwards is: Racecar!
ppbon is offline   Reply With Quote
Old 01-22-2012, 01:17 PM   #3
Pat
Registered User
 
Join Date: Jun 2007
Location: Littleton, CO
Posts: 456
You're not reaching the limits of your brakes. You're reaching the limit of your tires. This is how it is supposed to work.
__________________
"Of all the extreme sports I've ever participated in- windsurfing, kite boarding, wake boarding, tow-in surfing and snowboarding- skiing, for me, made everything else easy."
-Chuck Patterson
Pat is offline   Reply With Quote
Old 01-23-2012, 07:52 PM   #4
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,429
Everyone should try this under safe conditions to become familar with the braking characteristics of their car and what it feels like to get into the ABS. This is usually the first exercise in a defensive driving school.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor
thstone is offline   Reply With Quote
Old 01-23-2012, 08:06 PM   #5
Porscheectomy
 
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
Quote:
Originally Posted by thstone View Post
This is usually the first exercise in a defensive driving school.
Stabbing the brakes and turning at the same time to avoid a simulated emergency situation is a great fundimental exercise.
blue2000s is offline   Reply With Quote
Old 01-23-2012, 08:53 PM   #6
Registered User
 
Join Date: Oct 2008
Location: San Diego
Posts: 434
I'm not sure why you see this as a problem. If you COULDN'T brake hard enough to make the ABS fire, you'd have a problem.

Sometimes my starter engages when I turn the key... any idea what might be wrong?
__________________
1999 Carrera 4 Aero kit 4" UD Pulley
My Corvette doesn't leak oil... it sweats horsepower.
sd_boxster is offline   Reply With Quote
Old 01-24-2012, 10:38 AM   #7
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,429
Quote:
Originally Posted by blue2000s View Post
Stabbing the brakes and turning at the same time to avoid a simulated emergency situation is a great fundimental exercise.
That is the second skill taught!
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor
thstone is offline   Reply With Quote
Old 01-29-2012, 09:13 PM   #8
Registered User
 
Join Date: Sep 2010
Location: Singapore
Posts: 228
Interesting topic... I think I have the reverse of the TS....

At high speeds if I brake hard, on my front brakes, the abs actually sometimes allows the tires to skid (???!!!) slightly, usually just one sound then no skidding but no abs as well. If I step any harder, the ABS will kick in. The skid usually last a split second to at most a second.

I've changed abs sensors on all 4 brakes and even changed the front brakes to the S brakes, but it still behaves the same.

It's as though I've got "lazy" abs that is pretty slow in engaging.

My mechanic says its normal as "Porsche determined this way you get the most effective braking". Don't know whether to believe him or not ?? I've never had a car with abs that allowed any skidding !

My front tires are PS3 and the rears are N specs PS2, if that makes a difference.

Any thoughts ? I hope it's not the abs unit... those things are expensive !

Last edited by shlim8; 01-29-2012 at 09:20 PM.
shlim8 is offline   Reply With Quote
Old 01-30-2012, 06:41 AM   #9
Registered User
 
jaykay's Avatar
 
Join Date: Sep 2009
Location: toronto
Posts: 2,277
An every so slight skid; whining of the tires is where you want to be for the best stopping distance. Getting right into the ABS is less effective.

Should you not have ABS, you will have to come off the brakes to "break and avoid" an obstacle or you will slide into said obstacle
__________________
00 986 S....with a few tweaks
jaykay is offline   Reply With Quote
Old 01-31-2012, 12:06 AM   #10
Registered User
 
Join Date: Sep 2010
Location: Singapore
Posts: 228
I'm not sure if I would describe mine as "slight skid" or "whining of the tires" - its a loud loud skid. But its not a sustained skid. As I mentioned, 99.99% of the time, the abs doesn't come on after that (if no increase in brake pedal pressure).

It's embarrasingly loud.

I did have a sustained skid once with the tail swinging out, but since changing the abs sensors and the engine mount (that seem to affect stability quite alot), haven't happened again. That time was on an emergency emergency stop at lower speeds even...

Quote:
Originally Posted by jaykay View Post
An every so slight skid; whining of the tires is where you want to be for the best stopping distance. Getting right into the ABS is less effective.

Should you not have ABS, you will have to come off the brakes to "break and avoid" an obstacle or you will slide into said obstacle
shlim8 is offline   Reply With Quote
Old 01-31-2012, 01:58 AM   #11
Registered User
 
Join Date: Feb 2011
Location: Algonquin, Misarikwack
Posts: 710
Would the climate/pavement type influence ABS at all? Silly question I know (don't flame me!) but I have the same loud tyre skid noise thing happening to me durring hot summer days. However durring mild-cold winter days, the ABS seems to be kicking in normally.
madmods is offline   Reply With Quote
Old 01-31-2012, 06:23 PM   #12
Registered User
 
Join Date: Sep 2010
Location: Singapore
Posts: 228
That would explain alot for me if weather did affect the abs.... it's hot here all year round !

Quote:
Originally Posted by madmods View Post
Would the climate/pavement type influence ABS at all? Silly question I know (don't flame me!) but I have the same loud tyre skid noise thing happening to me durring hot summer days. However durring mild-cold winter days, the ABS seems to be kicking in normally.
shlim8 is offline   Reply With Quote
Old 02-01-2012, 05:26 PM   #13
Registered User
 
Join Date: Oct 2008
Location: San Diego
Posts: 434
When you panic stop, you may initially hear a single chirp. Since the Boxster is so nicely balanced, the front wheel(s) momentarily break free in a panic stop. All that load you're piling onto the front suspension while decelerating pushes the tires more firmly into the pavement, causing the skid to stop. This is why you try on the track to load your brakes progressively instead of stabbing at the brake pedal - you want to shift load to the front suspension before threshold braking.

There's a spot on my way home where I love to chirp the front brakes during threshold braking. I had not realized until today that this is cause for embarrassment.
__________________
1999 Carrera 4 Aero kit 4" UD Pulley
My Corvette doesn't leak oil... it sweats horsepower.
sd_boxster is offline   Reply With Quote
Reply


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 On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 11:02 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page