StopTech Big Brake Kit

Stoptech Calipers for Wilhelm Raceworks Brake Kit

The ultimate MR2 brake kit!  Based on my Wilwood Heavy Duty kit, this kits adds Stoptech's ST-43 Race caliper for industry leading caliper stiffness, plus staggered pistons to combat pad taper wear.  Additionally, the piston sizes are specifically chosen to optimize brake bias for the MKII MR2.  You won't find these calipers anywhere else!

Wilhelm Raceworks Stoptech Front BBK Installed Wilhelm Raceworks Stoptech Rear BBK Installed

StopTech Brake Kit Installed

Wilhelm Raceworks BBK brackets and hardware

Wilhelm Raceworks Brackets, Hats, and Hardware

The complete Wilhelm Raceworks StopTech Brake Kit consists of the following parts:

  • Wilhelm Raceworks aluminum caliper brackets, front and rear
  • Hardware for attaching the brackets and calipers
  • Four Wilhelm Raceworks aluminum rotor hats
  • Socket head cap screws and "jet nuts" for attaching rotors to hats
  • Techna-Fit Steel braided brake lines front and rear
  • Aluminum bracket for parking brake calipers with attachment hardware
  • Custom parking brake cables
  • 2x StopTech ST43 Race front calipers
    • 30mm/34mm staggered pistons for stock NA or adjustable proportioning valve
    • 34mm/38mm staggered pistons for stock Turbo proportioning valve
  • 2x StopTech ST43 Race rear calipers 
    • 26mm/28mm staggered pistons
  • 2x Wilwood MC4 mechanical calipers
  • 2x Wilwood HD curved vane front rotors
  • 2x Wilwood HD curved vane rear rotors
  • StopTech Sport brake pads, suitable for street and moderate track use (other pads available on request)


SKU StopTech Big Brake Kit
* Kit Type:

* Rotor Options:

* Caliper Color:

* Caliper Piston Sizing:

Adjustable proportioning valve kit available here.

Installation Instructions 

-The StopTech calipers in this kit are made to order.  Lead time is currently about 12 weeks.
-The calipers included in this kit do not include dust seals.  This can be a problem for passing inspections in some locations.
-If you have a favorite brand of brake pads you wish to use, the pads can be eliminated from the kit, or an alternate pad can be substituted.  Please contact me to submit a custom order if you would like pads other than the standard StopTech Sport pad.

Beginning July 2019, all brake Wilhelm Raceworks brake kits come with socket head cap screws and Mil-Spec MS21042-5 self locking "jet nuts" for attaching the rotors to the hats.  NO MORE SAFETY WIRE REQUIRED!  If you have an older kit and want to convert to the new attachment I can modify your hats for $10 each, plus $10 per rotor for the new hardware kit. 

Rotor hardware

Technical Info


This kit can use virtually any 12.19" rotor with an 8x7.00" bolt pattern, 1.25" thickness for the front and .81" thickness for the rear.  There are numerous options from various manufacturers including Wilwood, Afco, Colman Racing, and many others.  They are available with straight or curved vanes, and slotted, cross drilled, or both.  The Wilwood options are shown in the chart below.  There are many others on the market as well.  Be sure to purchase one right and one left if buying curved vane rotors!

Front Rotors (12.19"x1.25")
Model LH Part # RH Part # Vane Style Price Weight
Wilwood GT48 (slotted) 160-11840 160-11839 Curved $139 12.7lb
Wilwood HD48 160-11836 160-11835 Curved $125 12.7lb
Wilwood Ultralight 160-2895 160-2894 Curved $75 10.5lb
Rear Rotors (12.19"x.81")
Wilwood GT36 (slotted) 160-12292 160-12291 Curved $125 9.5lb
Wilwood HD36 160-12290 160-12289 Curved $104 9.5lb
Wilwood Ultralight 160-0277 160-0277 Straight $40 8.9lb



The StopTech calipers in this kit are custom made to my specifications to optimize brake bias for the MKII MR2.  Two front caliper options are available to suite either the stock turbo proportioning valve, or the NA or an aftermarket adjustable valve.   However, if you have a factory turbo I highly recommend either finding an NA proportioning valve for it, or installing an adjustable valve.  The overall resulting bias is better across a much wider range of deceleration rates.

The parking caliper used with the kit is the Wilwood MC4.   One of each LH/RH is required.

   Wilwood MC4 Parking Calipers
LH Part #  120-12070-BK
RH Part #  120-12069-BK

The part numbers above are the black powdercoated version.  Red and silver are also available.


Brake Pads

The StopTech ST43 caliper uses the same pad shape as the Wilwood Forged Superlite used in my Wilwood Heavy Duty kit. Many companies make pads in this shape in many different compounds, including but not limited to: StopTech, Wilwood, Porterfield, Performance Friction, Hawk, Raybestos, etc. 


Custom Parts / Clearances

The Wilhelm Raceworks hats and main caliper brackets in this kit are machined from 6061-T6 aluminum, and black anodized.  All are designed around the brake torque required for 1.4g deceleration, and with a factor of safety of 2x on the 500 million cycle fatigue strength of 6061-T6 aluminum.

The parking brake system in this kit is capable of achieving deceleration rates of ~.3g.  More than enough to pass the emergency brake function tests that I am aware of.  However, it is ultimately designed and intended to be a parking brake, or for that once-in-a-lifetime emergency situation.  If you are drifting or doing hand-brake turns, you may find it to be insufficient.

Assuming adequate spoke to caliper clearance, most 16" wheels should fit over the front brakes without issue.  The parking caliper in the rear might cause an issue with some 16" wheels.  Use the template below to check fit on your wheels before ordering.

Caliper Clearance Template for Stoptech Brake Kit

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