flatchat(Chris)
Supporter
Aussie RCR T70 capers
- Thread starter flatchat
- Start date
Chris:
Do your calipers have anti knockback springs installed in them? Some of the AP calipers come with them. They are come in 4lbs or 7 lbs. Most Nascar teams use them on road courses. Also the V-8 super car calipers have them also I believe. It may be the discs are distorting at high temps looks to me like they bolt solid from the photo. Most upper level discs are floating design to allow the disc to expand without distortion from the hat.
Do your calipers have anti knockback springs installed in them? Some of the AP calipers come with them. They are come in 4lbs or 7 lbs. Most Nascar teams use them on road courses. Also the V-8 super car calipers have them also I believe. It may be the discs are distorting at high temps looks to me like they bolt solid from the photo. Most upper level discs are floating design to allow the disc to expand without distortion from the hat.
flatchat(Chris)
Supporter
Willwood rotors 11.75" x 1.25" curved vane floating
Fresh dot 4 castrol brake fluid
Willwood calipers 6 and 4 pot
2lb residual valves
Tilton pedals
Pads were Hawk which seemed OK, recently changed to willwood
Wheel bearings all OK
The first few laps OK then symptoms of maybe boil back or more likely pad knock off -- a little unpredictable --long pedal and a couple pumps redeems itself for that instance
Noticeable pad residual stuck to the rotors
Your thoughts much appreciated
Fresh dot 4 castrol brake fluid
Willwood calipers 6 and 4 pot
2lb residual valves
Tilton pedals
Pads were Hawk which seemed OK, recently changed to willwood
Wheel bearings all OK
The first few laps OK then symptoms of maybe boil back or more likely pad knock off -- a little unpredictable --long pedal and a couple pumps redeems itself for that instance
Noticeable pad residual stuck to the rotors
Your thoughts much appreciated
Ron Earp
Admin
We had exactly the same setup as you down to the fluid and residual valves.
Except when looking at your pictures we had one big difference.
We had the area for the "fog lights" cut out and funneled to a hard molded duct that blew air in the center of the rotor. Even without that we always had that area cut out and it naturally allows air to the rotor. I think if you make this change you'll be fine. No way I'd consider running a track car without brake cooling.
Except when looking at your pictures we had one big difference.
We had the area for the "fog lights" cut out and funneled to a hard molded duct that blew air in the center of the rotor. Even without that we always had that area cut out and it naturally allows air to the rotor. I think if you make this change you'll be fine. No way I'd consider running a track car without brake cooling.
Residual valves would be the first thing I would look at. Generally any valve the causes line pressure can malfunction. Recirculators used to be common some years ago but some malfunctioned and caused drag. We never recommend them any more. How many vanes in the discs? What compound Hawk? What compound wilwood?
flatchat(Chris)
Supporter
Hmmm residual valves --I suspect ?
Hawk pad compound unknown
Will try air ducting next season
Rotors are 48 vane 160 11837 / 8
Brake Pads
High-Temperature Racing Pads
Pad#: 7420
Compound: BP-30
Wilwood Brake Pad Plate #7420
<Go Back>
Product Number: 150-9864K
Pad Dimensions
Thickness(in): Area(in²): Volume(in³): Beded:
.80 8.2 4.9 N
Temperature & Friction Ratings
Peak Temperture Rating: Peak Friction Rating:
1300+ F. 0.62
Dust & Noise Ratings
Dust Production Rating: Pad Noise Rating:
N-A N-A
Performance Characteristics
•High friction, smooth intitial response.
•Steady rise in friction as temperature increases.
•Low wear rate
•High friction, smooth intitial response.
Vehicle Applications
Driving Environment Vehicle Sub-Types Application Duty
Rally Heavy Duty
Road Race Heavy Duty
Late Model Asphalt ASA, All Pro, SW Tour, etc... Heavy Duty
Stock Cars NASCAR, BGN, CTS, ARCA, etc... Heavy Duty
Late Model Dirt STARS, UMP, IMCA, etc... Heavy Duty
Northeast Modified Dirt or Pavement Heavy Duty
Open Wheel Sprint, Midget, etc… Dirt or Pavement Heavy Duty
Off Road Heavy Duty
Pad Illustration and Dimensions
Hawk pad compound unknown
Will try air ducting next season
Rotors are 48 vane 160 11837 / 8
Brake Pads
High-Temperature Racing Pads
Pad#: 7420
Compound: BP-30
Wilwood Brake Pad Plate #7420
<Go Back>
Product Number: 150-9864K
Pad Dimensions
Thickness(in): Area(in²): Volume(in³): Beded:
.80 8.2 4.9 N
Temperature & Friction Ratings
Peak Temperture Rating: Peak Friction Rating:
1300+ F. 0.62
Dust & Noise Ratings
Dust Production Rating: Pad Noise Rating:
N-A N-A
Performance Characteristics
•High friction, smooth intitial response.
•Steady rise in friction as temperature increases.
•Low wear rate
•High friction, smooth intitial response.
Vehicle Applications
Driving Environment Vehicle Sub-Types Application Duty
Rally Heavy Duty
Road Race Heavy Duty
Late Model Asphalt ASA, All Pro, SW Tour, etc... Heavy Duty
Stock Cars NASCAR, BGN, CTS, ARCA, etc... Heavy Duty
Late Model Dirt STARS, UMP, IMCA, etc... Heavy Duty
Northeast Modified Dirt or Pavement Heavy Duty
Open Wheel Sprint, Midget, etc… Dirt or Pavement Heavy Duty
Off Road Heavy Duty
Pad Illustration and Dimensions
flatchat(Chris)
Supporter
Hmmm Wobbly front rotors seems to be the problem --guess we shouda bought the pre bedded items.
So, now that they are all nicely stress relieved and bedded, remachined true and try again
So, now that they are all nicely stress relieved and bedded, remachined true and try again
Chris, how may sets have you been through on the car?
Chris
Are you getting stub axle flex, this will give pad knock off.
A way of checking is before entering a corner make sure you have a pedal, after exit check if it has gone away.
The flex will cause the disk to push the pad back.
Does Ron have the same set up.
Jim
Are you getting stub axle flex, this will give pad knock off.
A way of checking is before entering a corner make sure you have a pedal, after exit check if it has gone away.
The flex will cause the disk to push the pad back.
Does Ron have the same set up.
Jim
flatchat(Chris)
Supporter
Ducting underway (I am listening Ron :thumbsup
3rd set of front rotors --onto the 48 vane ones all round now --the left front had about .030" buckle and right was .015"-- machined true now
Corvette c4 wheel hubs Timkin brngs true and firm.
The car doesn't get used much, but when you spend quality race time farking with things --well, ya just go home dissappointed instead of feeling good about blowing Porsche cup cars door handles off :laugh:
3rd set of front rotors --onto the 48 vane ones all round now --the left front had about .030" buckle and right was .015"-- machined true now
Corvette c4 wheel hubs Timkin brngs true and firm.
The car doesn't get used much, but when you spend quality race time farking with things --well, ya just go home dissappointed instead of feeling good about blowing Porsche cup cars door handles off :laugh:
Send me a pic of your rotor hats with discs mounted...didn't you make some different ones ?..
flatchat(Chris)
Supporter
see post #120 -- hats are as supplied by RCR they are good and run true
The rotor location diameter was machined down a bit to allow for rotor contraction
The rotor location diameter was machined down a bit to allow for rotor contraction
OK...that was going to be my suggestion....you are a smart fella afterall....
Ron Earp
Admin
Now I remember, we did have to do that to the hats to account for rotor expansion. Cracked something one time, I think it was the rotor, but after that episode we were good to go.
In the end with the ducts hooked up the car braked beautifully. Stop after stop, no issues even with long track sessions or racing. We used high quality bearings too, although the cheaper once didn't give us any problems either I prepped them with the expensive stuff for the 13 hour.
flatchat(Chris)
Supporter
Problem solvered --- rotors all running true, residual valves still in, some venting and using Hawk DTC 60 pads, after some bedding in procedure we gave 'em a bit of a work out and they are good - real good! --happy now:thumbsup:
I have used those in front and DTC70s in the rear to great effect too
flatchat(Chris)
Supporter
I use their calipers on my full race cars...same as used on a DP car.
