Ever since we upgraded the front brakes on the Project GT-R, the braking was very capable at 118 feet but we want it too be great. With the addition of monster rears, we hope to dip below 110 and with fresh H8 Track compound pads are aiming for sub-100! We started by contacting Lee Takagi, General Manager of Rotora USA about a rear system for the car. Takagi suggested we go with the 4-piston / 330mm kit complete with lines and some H2 compound street / track pads.
We contacted our installer Vuk over at AMS (www.amszstore.com) to hook the rears up for us. The install was textbook and we topped the system back up with some Motul RBF600 DOT5 brake fluid. The only thing that requires some degree of custom fab was the rear dust shield. Vuk explained that the dust shield is a curious beast on the rear setup because it has several rivets to the hub itself. A complete disassembly and drilling out the rivets would be a waste of labor, which isn’t free. So we opted to cutout the dust shield with some tin snips and smooth out the burrs a bit with a Dremel tool.
BEDDING-IN PROCEDURE
Another thing to ensure before you get crazy is to clean the rotors with brake cleaner. This gets rid of any film that will affect braking, so it’s metal on pad compound all the way. Following a proper bedding-in process will ensure a solid transfer film on the rotors with no hot spots or uneven wear. It will also properly heat-treat the rotors to prevent cracking or warping in the future. The procedure is simple but finding a safe area with no interruptions is nearly impossible. Originally we planned to do this either late night or early morning when there was no traffic. Why? Well because we will be doing some Ferrari-esque stops and not every other motorist knows how to react to that.
Without any hard stops or dragging the brakes navigate to the nearest empty highway. Take the car up to 100km/h (65mph) and jam the brakes just to the point of engaging ABS all the way down to 25km/h (15mph). It should be a hard stop and it will improve as you heat up the pads by repeating 8-10 times. Try to have no long gaps in between the hard stops and do not come to full stop as it would imprint the pad on the rotor and cause vibration. At the end of the cycle, there may be a noticeable bit of fade but this is totally normal as the system beds-in. After these solid stops, let the system cool down for a 15 minute brake-free drive to chill everything out. The massive rear rotors filled up the wheel nicely and turned a healthy bluish gunmetal color. The Rotoras were now ready for the track but we suggest the optimal performance will be seen after about 500km (300mi).
TRACK MODE
Simply having the 6-piston / 355mm fronts onboard was insane enough, now the braking is just plain stupid. The pedal feel is more direct by replacing the stock rubber lines with Rotora’s stainless lines. There is enough brake there to engage the seat belt locks with not much effort, so your passengers better be strapped in.
The test track at the Dunnville Autodrome would provide three areas where we could decelerate from triple digits down to nothing. Turn one provides an area where we can reach 180km/h (112mph) and take it down to under the speed limit in order to make the corner. After the Nitto NT-01 slicks were warmed up, we attacked the front straight like a cage fighter and prepared for the first serious stop on the new system. At the 3rd marker we decided to hammer it and the car came down to a manageable speed well before the corner. It tracked straight and true with no sense of an uneven bias. It felt as if the new rear brakes flattened the braking more as the pressure is more even. With the stock 2-pistons onboard it was a bit of a mismatch. The two other major braking zones, proved that the Rotoras were there on demand and the confidence to make late-braking moves increased. Approaching 10 laps and the brakes felt as if they weren’t even tested yet, there was so much left. It was clear, the upgrades and Motul did a lot for this system and that the balance of the OE equipment is quite healthy.
We hooked-up our G-Tech Pro RR and calibrated it to the best possible performance. After several 60-0mph stabs we came up with some serious numbers beating the previous record. The test was admittedly slightly improved due to conditions on the warm track and running R-Compounds as opposed to Bridgestone RE-01R on cold pavement before.
The ABS kicked in everytime as the 3,170-pound GT-R hurled to a stop in only 110 feet. This is a lot of clamping force for such a light car considering heavier exotics have comparable systems. The new stopping distance places the GT-R ahead of the Lamborghini Murcielago but behind the Z06. The ultimate goal is to surpass the new GT-R and chase that Viper.
SUPERCAR braking |
|
Dodge Viper SRT-10 |
97ft |
Mosler MT900 Photon |
100ft |
Nissan GT-R R35 |
104ft |
Mitsubishi EVO MR |
104ft |
Corvette Z06 |
105ft |
Project GT-R |
110ft |
Lamborghini Murcielago |
111ft |
Mitsubishi EVO X GSR |
111ft |
Mercedes CL55 AMG |
113ft |
Subaru STi |
114ft |
Ferrari 575M Maranello |
115ft |
Project GT-R (Aug ’07) |
118ft |