[Z06] Wildwood Big brake kit came in...Yay!!!
07-16-2014, 07:57 PM
#9
Instructor
Thread Starter
I agree about the spacers. Other than that I'm ok with it. I can't wait to start yanking out my stockers. Can anyone chime in on the brake feel between the stock and this kit? Hows the stopping between the 2? Need some input.
07-16-2014, 09:54 PM
#10
Team Owner
19/20 required to fit these, or would they fit with a 18/19 setup?
07-17-2014, 12:35 AM
#11
Intermediate
I have the same brakes - no clearance issue with the OEM 18/19 spyder wheels. In my case, they did feel different. I noticed a slight increase in pedal stroke and a slight decrease in firmness. This concerned me because that change in feel could also indicate residual air in the system. After bleeding the calipers several times without producing any air, I crunched the numbers and determined that there is an increase of surface area of the pistons. If I got the numbers right, the fronts have 1.6% more surface area, but more significantly, the rears have 12% more surface area. The net effect is a slightly higher leverage ratio, as well as slightly more rear bias (a good thing - these cars do benefit from more rear bias). Correspondingly, there is slightly less pedal pressure required to develop the same amount of brake torque. They are certainly very powerful on the street, but unfortunately, I haven't yet been able to run them on the track, which is where the performance difference should be more noticeable, so I can't speak to that. Note, I'm using Carbotech 1521 street pads, which may also have a different feel than the Wilwood pads that come with the kit. After you've used them a bit, check the tightness of the two inner bolts of the four bolts that hold the caliper halves together to make sure they're still tight. I found that they can loosen ever so slightly (or may not have been fully tightened by Wilwood), which allows some extra flex thereby causing a slight increase in pedal travel.
There is quite a bit of manufacturing tolerance in the uprights and hubs, so the shims allow you to accurately center the calipers on the rotors. I ended up with different shim stacks on each corner. The shims on the radial caliper mounting studs also allow for manufacturing tolerance in the uprights as well as the pads and thus allow you to place the edge of the brake pad material exactly flush with the edge of the rotor as specified by Wilwood.
Installation note... Watch out for the problem with distorted threads at the chassis hard line connection as discussed in another thread. I experienced the same difficulty with tight, distorted threads on my front brake fittings from having been over-tightened at the factory. The rears were okay. A distorted thread makes it very difficult to tell if you're cross-threading it when installing the Wilwood flex hose adapter. Very stressful not knowing if you're ruining your threads or not while hurrying to install an adapter whilst fluid is dripping out of the line. For me, the front fittings screwed in much harder than they should, but not quite as hard as they would if cross-threaded. It can be a fine line. If you encounter this problem, best to go slowly and carefully, sacrifice some fluid, and have a friend monitoring the reservoir and adding fluid as needed.
I got the kit with replacement pins and retaining clips to have on hand in case one of the clips flies off and disappears when changing pads. Another way to go... The pins can be replaced with 4-1/2 inch long (IIRC), 1/4" diameter, hardened bolts to dispense with the clips - details posted in another thread.
There is quite a bit of manufacturing tolerance in the uprights and hubs, so the shims allow you to accurately center the calipers on the rotors. I ended up with different shim stacks on each corner. The shims on the radial caliper mounting studs also allow for manufacturing tolerance in the uprights as well as the pads and thus allow you to place the edge of the brake pad material exactly flush with the edge of the rotor as specified by Wilwood.
Installation note... Watch out for the problem with distorted threads at the chassis hard line connection as discussed in another thread. I experienced the same difficulty with tight, distorted threads on my front brake fittings from having been over-tightened at the factory. The rears were okay. A distorted thread makes it very difficult to tell if you're cross-threading it when installing the Wilwood flex hose adapter. Very stressful not knowing if you're ruining your threads or not while hurrying to install an adapter whilst fluid is dripping out of the line. For me, the front fittings screwed in much harder than they should, but not quite as hard as they would if cross-threaded. It can be a fine line. If you encounter this problem, best to go slowly and carefully, sacrifice some fluid, and have a friend monitoring the reservoir and adding fluid as needed.
I got the kit with replacement pins and retaining clips to have on hand in case one of the clips flies off and disappears when changing pads. Another way to go... The pins can be replaced with 4-1/2 inch long (IIRC), 1/4" diameter, hardened bolts to dispense with the clips - details posted in another thread.
07-17-2014, 11:35 AM
#12
Instructor
Thread Starter
I have the same brakes - no clearance issue with the OEM 18/19 spyder wheels. In my case, they did feel different. I noticed a slight increase in pedal stroke and a slight decrease in firmness. This concerned me because that change in feel could also indicate residual air in the system. After bleeding the calipers several times without producing any air, I crunched the numbers and determined that there is an increase of surface area of the pistons. If I got the numbers right, the fronts have 1.6% more surface area, but more significantly, the rears have 12% more surface area. The net effect is a slightly higher leverage ratio, as well as slightly more rear bias (a good thing - these cars do benefit from more rear bias). Correspondingly, there is slightly less pedal pressure required to develop the same amount of brake torque. They are certainly very powerful on the street, but unfortunately, I haven't yet been able to run them on the track, which is where the performance difference should be more noticeable, so I can't speak to that. Note, I'm using Carbotech 1521 street pads, which may also have a different feel than the Wilwood pads that come with the kit. After you've used them a bit, check the tightness of the two inner bolts of the four bolts that hold the caliper halves together to make sure they're still tight. I found that they can loosen ever so slightly (or may not have been fully tightened by Wilwood), which allows some extra flex thereby causing a slight increase in pedal travel.
There is quite a bit of manufacturing tolerance in the uprights and hubs, so the shims allow you to accurately center the calipers on the rotors. I ended up with different shim stacks on each corner. The shims on the radial caliper mounting studs also allow for manufacturing tolerance in the uprights as well as the pads and thus allow you to place the edge of the brake pad material exactly flush with the edge of the rotor as specified by Wilwood.
Installation note... Watch out for the problem with distorted threads at the chassis hard line connection as discussed in another thread. I experienced the same difficulty with tight, distorted threads on my front brake fittings from having been over-tightened at the factory. The rears were okay. A distorted thread makes it very difficult to tell if you're cross-threading it when installing the Wilwood flex hose adapter. Very stressful not knowing if you're ruining your threads or not while hurrying to install an adapter whilst fluid is dripping out of the line. For me, the front fittings screwed in much harder than they should, but not quite as hard as they would if cross-threaded. It can be a fine line. If you encounter this problem, best to go slowly and carefully, sacrifice some fluid, and have a friend monitoring the reservoir and adding fluid as needed.
I got the kit with replacement pins and retaining clips to have on hand in case one of the clips flies off and disappears when changing pads. Another way to go... The pins can be replaced with 4-1/2 inch long (IIRC), 1/4" diameter, hardened bolts to dispense with the clips - details posted in another thread.
There is quite a bit of manufacturing tolerance in the uprights and hubs, so the shims allow you to accurately center the calipers on the rotors. I ended up with different shim stacks on each corner. The shims on the radial caliper mounting studs also allow for manufacturing tolerance in the uprights as well as the pads and thus allow you to place the edge of the brake pad material exactly flush with the edge of the rotor as specified by Wilwood.
Installation note... Watch out for the problem with distorted threads at the chassis hard line connection as discussed in another thread. I experienced the same difficulty with tight, distorted threads on my front brake fittings from having been over-tightened at the factory. The rears were okay. A distorted thread makes it very difficult to tell if you're cross-threading it when installing the Wilwood flex hose adapter. Very stressful not knowing if you're ruining your threads or not while hurrying to install an adapter whilst fluid is dripping out of the line. For me, the front fittings screwed in much harder than they should, but not quite as hard as they would if cross-threaded. It can be a fine line. If you encounter this problem, best to go slowly and carefully, sacrifice some fluid, and have a friend monitoring the reservoir and adding fluid as needed.
I got the kit with replacement pins and retaining clips to have on hand in case one of the clips flies off and disappears when changing pads. Another way to go... The pins can be replaced with 4-1/2 inch long (IIRC), 1/4" diameter, hardened bolts to dispense with the clips - details posted in another thread.
Last edited by C6ZO6Pilot; 07-17-2014 at 11:37 AM.
07-17-2014, 01:05 PM
#13
Intermediate
Thanks for the insight. I don't have a problem installing the kit...it's just the centering of the calipers part that will probably bug me. I'm assuming you torqued down everything and used a micrometer to measure the rotor to caliper clearances before using Loctite right? Assuming the pads are the same width, the gap in between the rotor and caliper should be the same on both ends right? Do you have pictures showing the install?
07-18-2014, 10:20 AM
#14
Tech Contributor
Member Since: Oct 1999
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No need to use a micrometer. All you have to do is eye ball centering of the caliper on the rotor. When I installed my Wilwoods I didn't have to use any shims to center the calipers or to adjust the calipers radially.
From a piston area standpoint brake bias will shift slightly rearward since the rear to front ratio for the stock calipers is 1.815 whereas it is 1.642 for the Wilwood W6A/W4A combo. Of course this depends on which diameter pistons are installed in the Wilwood calipers if you are piecing a kit together Vs using a standard kit.
I am using a 14 inch stock size rotor in front which is a quarter inch smaller in diameter than the standard Wilwood BBK that includes caliper and rotor. That with the standard Wilwood rear BBK with 14 inch rotors adds more rear bias due to the .6 inch increase in rear rotor diameter.
Brake pedal feels the same as it did with stock calipers.
Bill
From a piston area standpoint brake bias will shift slightly rearward since the rear to front ratio for the stock calipers is 1.815 whereas it is 1.642 for the Wilwood W6A/W4A combo. Of course this depends on which diameter pistons are installed in the Wilwood calipers if you are piecing a kit together Vs using a standard kit.
I am using a 14 inch stock size rotor in front which is a quarter inch smaller in diameter than the standard Wilwood BBK that includes caliper and rotor. That with the standard Wilwood rear BBK with 14 inch rotors adds more rear bias due to the .6 inch increase in rear rotor diameter.
Brake pedal feels the same as it did with stock calipers.
Bill
07-18-2014, 11:17 AM
#15
Former Vendor
No need to use a micrometer. All you have to do is eye ball centering of the caliper on the rotor. When I installed my Wilwoods I didn't have to use any shims to center the calipers or to adjust the calipers radially.
Brake pedal feels the same as it did with stock calipers.
Bill
Brake pedal feels the same as it did with stock calipers.
Bill
Good tech as always Bill.Remember tho that your front kit is the prototype TCE W6A caliper kit for the stock rotor upon which the Wilwood factory kits were derived. I didn't factor any shimming into the build on those kits. The later Wilwood factory production kits come with both lateral centering shims as well as shims/spacer for fitting both the 13.6 and 14" rotors to the same bracket. (*a good idea not in my original plan!)
Most centering should be done equally spaced. A need for more shim top or bottom may be a sign of bent spindle ears or a very lose hub bearing. Radial shimming to the stud should place the pad flush to the edge of the disc- normally Wilwood seems to factor the need for 2-3 shims for this. Failure to use these can result in bridge contact to the rotor once things get good and hot and the rotor expands. Not a good thing!
Proper bled and bed the resultant pedal feel should be near stock and offer greater tactical feel than stock making the drive more enjoyable!
Congrats on your purchase, many happy mile/smiles.
07-18-2014, 12:20 PM
#16
Instructor
Thread Starter
Good tech as always Bill.Remember tho that your front kit is the prototype TCE W6A caliper kit for the stock rotor upon which the Wilwood factory kits were derived. I didn't factor any shimming into the build on those kits. The later Wilwood factory production kits come with both lateral centering shims as well as shims/spacer for fitting both the 13.6 and 14" rotors to the same bracket. (*a good idea not in my original plan!)
Most centering should be done equally spaced. A need for more shim top or bottom may be a sign of bent spindle ears or a very lose hub bearing. Radial shimming to the stud should place the pad flush to the edge of the disc- normally Wilwood seems to factor the need for 2-3 shims for this. Failure to use these can result in bridge contact to the rotor once things get good and hot and the rotor expands. Not a good thing!
Proper bled and bed the resultant pedal feel should be near stock and offer greater tactical feel than stock making the drive more enjoyable!
Congrats on your purchase, many happy mile/smiles.
07-18-2014, 12:38 PM
#17
Intermediate
The mounting brackets in my kits have different part numbers front and rear, and did not require extra shims on the studs in front or back to make up a height difference. I have the same part numbers for the kits as the OP, but mine were purchased a year ago. Production change? Dunno.
07-18-2014, 05:52 PM
#19
Instructor
Thread Starter
07-18-2014, 06:25 PM
#20
Former Vendor
They would be used as needed, equally, on both yes. I believe it will stated this in the text.
Don't yell at me..I'm not the one who did the drawing!
