Weak Braking with Square R-comps
Thread Starter
Advanced
Joined: Sep 2013
Posts: 63
Likes: 1
From: Saltsburg PA
Weak Braking with Square R-comps
I will try my best to explain this in a way that makes sense.. I know there will most likely be question to follow...
Car is a 97 Coupe M6. It is used mainly for Autox. All brake components are stock with the exception of steel braided lines.
The problem that is occurring is during autox, more often than not the car experieces very weak braking ability... stops very slowly and doesn't even give enough bite to cause the abs to kick in. This is only occurring with my autox setup on... 17x9 with 275 40 17 at all 4 corners R-comp.
Sometimes the double tap technique on the brakes causes it to bite hard but not always.
Is this a problem with a square setup?
Car is a 97 Coupe M6. It is used mainly for Autox. All brake components are stock with the exception of steel braided lines.
The problem that is occurring is during autox, more often than not the car experieces very weak braking ability... stops very slowly and doesn't even give enough bite to cause the abs to kick in. This is only occurring with my autox setup on... 17x9 with 275 40 17 at all 4 corners R-comp.
Sometimes the double tap technique on the brakes causes it to bite hard but not always.
Is this a problem with a square setup?
Racer
Joined: Feb 2005
Posts: 332
Likes: 22
From: Georgia
Sounds like air in the lines, calipers or ABS system. I would rebleed with scan tool to purge ABS and see if the problem persists. I wouldn't ask if I had not recently done it, but have you or anyone else had your calipers off the car? I accidentally switched my left and right front during reinstall and even after multiple bleeds I had terrible brake pedal feel. Obviously the bleeder being on the bottom of the caliper wasn't evacuating all the air. 
"Double pumping" the pedal would compress the air briefly and the second quick pump would improve braking, but it was still not close to being correct. Switched the calipers, duh, and all was happy in brake land.
"Double pumping" the pedal would compress the air briefly and the second quick pump would improve braking, but it was still not close to being correct. Switched the calipers, duh, and all was happy in brake land.
Thread Starter
Advanced
Joined: Sep 2013
Posts: 63
Likes: 1
From: Saltsburg PA
Sounds like air in the lines, calipers or ABS system. I would rebleed with scan tool to purge ABS and see if the problem persists. I wouldn't ask if I had not recently done it, but have you or anyone else had your calipers off the car? I accidentally switched my left and right front during reinstall and even after multiple bleeds I had terrible brake pedal feel. Obviously the bleeder being on the bottom of the caliper wasn't evacuating all the air. "Double pumping" the pedal would compress the air briefly and the second quick pump would improve braking, but it was still not close to being correct. Switched the calipers, duh, and all was happy in brake land.
"Double pumping" the pedal would compress the air briefly and the second quick pump would improve braking, but it was still not close to being correct. Switched the calipers, duh, and all was happy in brake land.Last edited by TBuskey; Jul 15, 2014 at 07:47 PM.
Supporting Vendor
Joined: Oct 2002
Posts: 50,281
Likes: 518
From: Cleveland OH
St. Jude Donor '11,'13
you may want to change to a pad with a higher heat capability and better bite. For instance the Carbotech AX6 pad description is below.
The AX6™ is specifically engineered for Autocross applications. A high torque brake compound delivering reliable and consistent performance over a very wide operating temperature range of 50°F to 1000°F + (10°C to 537°C+). The advanced compound matrix provides an excellent initial bite, high coefficient of friction at lower temperatures along with very progressive brake modulation and release characteristics. Many drivers use the AX6™ for street driving as well, even though Carbotech™ doesn't recommend street driving with AX6™ due to possible elevated levels of dust and noise. AX6™ is NOT recommended as a race compound in most applications.
F: $163 R: $140 Includes 5% forum discount. Promo code z28.
The AX6™ is specifically engineered for Autocross applications. A high torque brake compound delivering reliable and consistent performance over a very wide operating temperature range of 50°F to 1000°F + (10°C to 537°C+). The advanced compound matrix provides an excellent initial bite, high coefficient of friction at lower temperatures along with very progressive brake modulation and release characteristics. Many drivers use the AX6™ for street driving as well, even though Carbotech™ doesn't recommend street driving with AX6™ due to possible elevated levels of dust and noise. AX6™ is NOT recommended as a race compound in most applications.
F: $163 R: $140 Includes 5% forum discount. Promo code z28.
Thread Starter
Advanced
Joined: Sep 2013
Posts: 63
Likes: 1
From: Saltsburg PA
you may want to change to a pad with a higher heat capability and better bite. For instance the Carbotech AX6 pad description is below.
The AX6™ is specifically engineered for Autocross applications. A high torque brake compound delivering reliable and consistent performance over a very wide operating temperature range of 50°F to 1000°F + (10°C to 537°C+). The advanced compound matrix provides an excellent initial bite, high coefficient of friction at lower temperatures along with very progressive brake modulation and release characteristics. Many drivers use the AX6™ for street driving as well, even though Carbotech™ doesn't recommend street driving with AX6™ due to possible elevated levels of dust and noise. AX6™ is NOT recommended as a race compound in most applications.
F: $163 R: $140 Includes 5% forum discount. Promo code z28.
The AX6™ is specifically engineered for Autocross applications. A high torque brake compound delivering reliable and consistent performance over a very wide operating temperature range of 50°F to 1000°F + (10°C to 537°C+). The advanced compound matrix provides an excellent initial bite, high coefficient of friction at lower temperatures along with very progressive brake modulation and release characteristics. Many drivers use the AX6™ for street driving as well, even though Carbotech™ doesn't recommend street driving with AX6™ due to possible elevated levels of dust and noise. AX6™ is NOT recommended as a race compound in most applications.
F: $163 R: $140 Includes 5% forum discount. Promo code z28.
Where does the AX6 fall in comparison to the hawk line? I have used HP+ before.
Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
hp+ is a great street/autocross pad and would likely solve your problem
the reason it's so noticeable on sticky tires is the increase in grip. harder street tires would break
this same reason is also why slicks are so hard on clutches
the reason it's so noticeable on sticky tires is the increase in grip. harder street tires would break
this same reason is also why slicks are so hard on clutches
Last edited by racebum; Jul 15, 2014 at 08:40 PM.
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Supporting Vendor
Joined: Oct 2002
Posts: 50,281
Likes: 518
From: Cleveland OH
St. Jude Donor '11,'13
Being that I didn't put the pads on and they are most likely the cheapest pads available.... Pad failure is a definite possibility. Good thought. I was forgetting the extra bite needed to cause lock up with the r-comps... I was too hung up on a possible ABS malfunction due to wrong size tires in rear.....I think pads may be the fix. Thanks!
Where does the AX6 fall in comparison to the hawk line? I have used HP+ before.
Where does the AX6 fall in comparison to the hawk line? I have used HP+ before.
A high torque brake compound with a wide operating temperature range of 200°F-1250°F+ (93°C to 676°C+). Carbotech™ XP8™ is the first of our racing compounds. Good initial bite at race temperatures, high coefficient of friction, excellent modulation and release characteristics. Extremely high fade resistance and very rotor friendly. Perfect for track day use with any tire and can still be driven safely to and from the track. Carbotech™ does NOT recommended XP8™ as a daily driven street pad due to elevated levels of dust and noise. Carbotech™ XP8™ is a great compound on the front & rear of most open wheel and sports racers.