Project Mu Brake Pads

July 2023 Comments made by others suggested that Project Mu HC-EP brake pads may offer improved braking. According to the data on the Project Mu website they do offer a considerable improvement in Friction Coefficient compared to other pads I had been using. The Friction Coefficient range of 0.43 to 0.58μ is a lot better than the 0.3 to 0.4μ of standard pads.  The higher the coefficient of friction, the less fluid pressure (lighter push of the brake pedal) is required to create a high braking force.

March 2024 The Project Mu brake pads did provide much better braking, but had the undesired problem of over heating the brake fluid after a few laps. Some research revealed that Torque RT700 was the best option to try. Torque RT700 brake fluid offered the highest wet and dry boiling points along with one of the lowest compressibility figures. Titanium shims were also fitted and some ducting added to direct air over the callipers was also incorporated. The brake pedal effort required to stop the car was now much improved and stayed consistent over a 5 lap sprint event.

May 2024 I decided to make the same changes to the rear brakes - Project Mu HC-EP pads and Torque RT700 brake fluid. 

thumb torque rt700

 

Brake Pads  Front Pads Rear Pads
Part Numbers F236 HC-EP R236 HC-EP

 

 

 

Brake Pedal Ratio

February 2021 The next upgrade to the brakes is to improve the hydraulic ratio on the front brakes. To do that I need to fit a larger master cylinder to the front brakes and that will make the pedal very hard to operate. The solution is to improve the pedal ratio. 

The standard pedal ratio is terrible at about 300mm to 75mm or about 4:1. To improve this I have lowered the pedal pivot by 20mm and raised the clevis pin hole by 20mm this now gives me a ratio of 300mm to 55mm or 5.5:1. This should still give me clearance around the steering column.

The original pivot pin is swaged and needs to ground away to remove the pin, Luckily the shaft is 12.5mm and easily substituted with a 1/2 inch high tensile bolt.

Note: The swaged end has a slighly conical appearance, You must grind this end off as the shaft has a step at the end.

brake pedal

Dual Master Cylinder

November - 2015 All the interior and engine bay had to be removed for the roll cage to fitted, So as part of the refit i decided to replace the standard booster/tandem master cylinder with a dual master cylinder and balance bar. I have used a Bicknell master cylinder and balance bar assembly which mounts at a 60deg angle to clear the strut tower. Fabrication of the mounting plate for the master cylinder and balance bar assembly is from 8mm 6061 aluminium.

October - 2017 Added an extra brace to the dual master cylinder mounts to help stop deflection of the firewall and the strut tower. Because of the staggered locations of the master cylinders, under heavy braking they push against the side of strut tower which bends out of the way. It also starts to push the fire wall inwards. Adding a brace from the fire wall to master cylinders removed most of the deflection and made the brake pedal a lot firmer.

extra bracing.jpg

ABS Removal

October - 2012 I finally found the time to remove the disabled ABS pump - Removal was the easy part - Re-plumbing the brake lines took a lot of time. The rear brake line was simple to refit as there is a joining block just under the steering column. The front brake lines were a bit more complex as a tee piece was required to join both left and right brake lines together. For the left front brake line I followed the original path along the top of the firewall and down the passenger side keeping the brake line as far away from the exhaust pipe as possible.

As most Japanese cars use the same type of brake lines, it was a case of go to the local wrecker and find brake lines of the required length. The replacement brake lines came from a Toyota Camry and the tee piece mounted on the booster came from a Hyundai Excel. ( See inset image )

abs removed 2

Rear Brakes

Jul -2012 The Nissan 200sx S15 single piston brake caliper & solid disk rotor rear brakes have been replaced with Nissan R33 GTST Skyline brake calipers and disk rotors. The Skyline has larger diameter ventilated disk rotors and 2 piston calipers. 

Unfortunately the Skyline uses a small internal drum brake for a hand brake. I have decided to go with in line hydraulic hand brake rather than mess around with drum brakes and hand brake cables

 

  Brake Rotor
Part Number
Rotor
Diameter
Rotor
Thickness
Caliper
Type
Disk Pad
Part Number

Original Brakes

(Nissan 200SX S15)

RDA906  258 mm 9 mm Single

QFM Performance

QDB 325

Replacement

(Skyline R33 GTST)

DBA 4908S

4000 Series T3

297 mm 18 mm Twin

QFM Performance

QDB 1220

 

Front Brakes

Jul -2012 : The Nissan 200sx S15 front brakes have been replaced with Nissan R33 GT-R Skyline brakes. The Skyline has larger diameter ventilated disk rotors and 4 piston Brembo brake calipers. Obtaining the Brembo brake calipers seems near impossible so at this stage i'm retaining the standard 4 piston brake calipers and using an adapter bracket from Gktech. The Rotors used are RDA replacement rotors for the R33

   
   Brake Rotor
Part Number
Rotor
Diameter
Rotor
Thickness
Caliper
Type
Disk Pad
Part Number

Original Brakes

(Nissan 200SX S15)

  280 mm 30 mm 4 Piston  

Replacement

(Skyline R33 GT-R)

RDA 7701

324 mm 30 mm 4 Piston

QFM Performance

QDB 1170

Oct 2013 : A slight upgrade to the front brakes has been made using the new Gktech adapters and Skyline R33 GTS-T aluminium calipers. The disk rotors were also replaced with a set of RDA grooved an dimpled versions.  This is a reasonably straight forward upgrade however there are two things to watch for.

#1. The difference in rotor diameter between the standard Nissan R33 GTS-T and the Brembo option rotors. The standard R33 STS-T disk rotor is 296mm in diameter where as the Brembo rotor is 324mm in diamter. This means the inner radius of the standard R33 calipers is too small and when first assembled the calipers will rub on the rotors. I made a cardboard template of the disk rotor and slowly reshaped the caliper using a die grinder.  

#2. The grooved and dimpled rotors are left and right handed. Take note of the labeling on the box as there is no markings on the actual rotors. If you forget there is an image on the RDA website showing the correct orientation.