01-22-2012, 11:45 AM
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#1
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Registered User
Join Date: May 2011
Location: Miami florida
Posts: 1,591
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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?
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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
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01-22-2012, 11:51 AM
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#2
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Registered User
Join Date: Nov 2005
Location: Florida
Posts: 529
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That is...
Quote:
Originally Posted by san rensho
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?
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... very normal.
Happy Boxstering,
Pedro
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Racecar spelled backwards is: Racecar!
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01-22-2012, 01:17 PM
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#3
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Registered User
Join Date: Jun 2007
Location: Littleton, CO
Posts: 456
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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.
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"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
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01-23-2012, 07:52 PM
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#4
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Certified Boxster Addict
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,669
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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.
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1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor
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01-23-2012, 08:06 PM
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#5
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Porscheectomy
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
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Quote:
Originally Posted by thstone
This is usually the first exercise in a defensive driving school.
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Stabbing the brakes and turning at the same time to avoid a simulated emergency situation is a great fundimental exercise.
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01-23-2012, 08:53 PM
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#6
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Registered User
Join Date: Oct 2008
Location: San Diego
Posts: 434
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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?
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1999 Carrera 4 • Aero kit • 4" UD Pulley
My Corvette doesn't leak oil... it sweats horsepower.
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01-24-2012, 10:38 AM
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#7
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Certified Boxster Addict
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,669
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Quote:
Originally Posted by blue2000s
Stabbing the brakes and turning at the same time to avoid a simulated emergency situation is a great fundimental exercise.
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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
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01-29-2012, 09:13 PM
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#8
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Registered User
Join Date: Sep 2010
Location: Singapore
Posts: 228
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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.
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01-30-2012, 06:41 AM
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#9
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Registered User
Join Date: Sep 2009
Location: toronto
Posts: 2,668
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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
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986 00S
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01-31-2012, 12:06 AM
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#10
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Registered User
Join Date: Sep 2010
Location: Singapore
Posts: 228
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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
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
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01-31-2012, 01:58 AM
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#11
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Registered User
Join Date: Feb 2011
Location: Algonquin, Misarikwack
Posts: 710
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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.
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01-31-2012, 06:23 PM
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#12
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Registered User
Join Date: Sep 2010
Location: Singapore
Posts: 228
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That would explain alot for me if weather did affect the abs.... it's hot here all year round !
Quote:
Originally Posted by madmods
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.
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02-01-2012, 05:26 PM
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#13
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Registered User
Join Date: Oct 2008
Location: San Diego
Posts: 434
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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.
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1999 Carrera 4 • Aero kit • 4" UD Pulley
My Corvette doesn't leak oil... it sweats horsepower.
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