Wilwood Big Brake Kit

Wilhelm Raceworks HD Brake Kit with optional slotted rotors

Improve braking performance for track / race use, without adding extra weight!  Many other kits on the market for MR2 utilize 323mm (12.72") rotors off of the Supra and RX8, and while these are an economical solution, at 21 lb for the front and 18 lb for the rear, the rotors are HEAVY.

Built around two piece 12.19" rotors, the Wilhelm Raceworks heavy duty kit saves 7-8lb per corner  (~30lb total) compared to a kit based on Supra / RX8 rotors.  The rotors are each about 3lb lighter than stock 93+ MR2 Turbo rotors.  The calipers save ~14lb compared to stock calipers, making the complete brake system weight nearly identical to 91 MR2 Turbo brakes.  Compared to the larger and heavier 93+ Turbo brakes, the heavy duty kit saves about 25lb.  The Ultralite kit saves another 10lb beyond that.

The kit uses Wilwood Forged Superlite (FSL) or Forged Narrow Dynalite (FNDL)  four piston calipers for all four corners plus Wilwood MC4 mechanical parking brake calipers.  Removal of the stock rotor dust shields is required.

Made in the USA!

Heavy Duty Big Brake Kit

Wilhelm Raceworks Heavy Duty Front BBK Installed Wilhelm Raceworks Heavy Duty Rear BBK Installed

Heavy Duty Brake Kit Installed

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

  • Aluminum caliper brackets, front and rear
  • Hardware for attaching the brackets and calipers
  • Four custom made 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 Wilwood FSL front calipers with 1.38" pistons
  • 2x Wilwood FSL rear calipers with 1.12" pistons (1.25" pistons for adjustable proportioning valves)
  • 2x Wilwood MC4 mechanical calipers
  • 2x Wilwood HD curved vane front rotors
  • 2x Wilwood HD curved vane rear rotors
  • Choice of Wilwood BP10 or BP20 brake pads, suitable for street and moderate track use (other pads available on request)


SKU Wilwood Heavy Duty Brake Kit
In Stock
* Kit Type:

Proportioning Valve Type:

Adjustable proportioning valve kits available here.

Installation Instructions

Ultralite Big Brake Kit

Wilhelm Raceworks Ultralite Brake Kit

For those looking for a more budget friendly and even lighter weight option the following kits use the Wilwood Forged Narrow Dynalite calipers and Wilwood Ultralite rotors.  The calipers and pads are slightly smaller, and the rotors are lighter weight.  Not only does this save you $350 on a complete kit, it saves an additional 10 lb off the brake system weight.  Suitable for street, autocross, and occasional track use.  If you are building a serious track car I recommend the HD kit.


SKU Wilwood Ultralite Brake Kit
In Stock
* Kit Type:

Installation Instructions

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

The Wilwood BP20 pads will handle quite a lot of track abuse in my experience, but they can be a little noisy when cold.  The BP10 is more street friendly.  Other pads are also available.  Please contact me if you wish to discuss substituting alternate pads.

For those looking for extra front wheel clearance, I can also substitute the thinner rear rotors and hats for the normal fronts, along with a narrower front caliper.  This will save you ~0.44in (11mm) of caliper to spoke clearance.

The standard calipers included in the complete kit provide a moderately conservative brake bias with the NA proportioning valve, and a more aggressive bias with the Turbo valve.
If you choose the adjustable proportioning valve option a larger rear caliper will be provided for better overall bias. Feel free to contact me if you wish to discuss brake bias in more detail.

Red or black powder coated calipers are special order items and will take an extra 3-4 weeks to deliver.

The calipers, rotors, and pads ship directly from a distributor and will arrive separately from the rest of the parts.

The calipers available for this kit do not include dust seals.  This can be a problem for passing inspections in some locations.

The HD or GT rotors are generally recommended for heavy track use.  The Ultralite rotors will work, but may need to be replaced more frequently.

Basic Big Brake Kit

Wilhelm Raceworks BBK brackets and hardware

If you prefer to purchase the rotors, calipers, and pads yourself, the basic kit consists of the following parts.

  • Aluminum caliper brackets, front and rear
  • Hardware for attaching the brackets and calipers
  • Four custom made 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

SKU Basic Brake Kit
In Stock
* Kit Type:

To complete your brake setup you will also need to purchase or already have:

  • 2x Wilwood FSL or FNDL calipers for front
  • 2x Wilwood FSL of FNDL calipers for rear
  • 2x Wilwood MC4 mechanical calipers
  • 2x 12.19" x 1.25" rotors with 8x7.00" bolt pattern
  • 2x 12.19" x .81" rotors with 8x7.00" bolt pattern
  • 2x Brake pad set for your choice of calipers

Installation Instructions

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 $153 12.7lb
Wilwood HD48 160-11836 160-11835 Curved $137 12.7lb
Wilwood Ultralight 160-2895 160-2894 Curved $82 10.5lb
Rear Rotors (12.19"x.81")
Wilwood GT36 (slotted) 160-12292 160-12291 Curved $137 9.5lb
Wilwood HD36 160-12290 160-12289 Curved $114 9.5lb
Wilwood Ultralight 160-0277 Straight $43 8.9lb



Caliper choice is important to optimize brake bias for maximum braking potential, while minimizing the chance of locking the rear brakes before the fronts.

For MR2s equipped with the non-turbo brake proportioning valve, the standard 1.38" / 1.12" calipers provide a slightly conservative bias.

For those with the turbo proportioning valve the 1.38" / 1.12" caliper combination will provide optimal bias at about 1g deceleration.  High grip race tires and high friction pads may require an adjustable proportioning valve, or a swap to the non-turbo proportioning valve.

When an adjustable proportioning valve is used, increasing the rear piston size to 1.25" will produce better bias over a wider range of deceleration rates.

More details on brake bias and the effects of various caliper / pad / proportioning valve combinations can be found on my Brake Bias page.  Please contact me if you have questions about choosing calipers for your setup.  Note: FSL = Forged Superlite, FNDL = Forged Narrow Dynalite

Recommended Wilwood Calipers
Part # Piston
Position Notes
FSL 120-11130 1.38" 1.25" Front Standard piston sizes supplied with kits.
FNDL 120-11576
FSL 120-11126 1.25" .81" Rear Adjustable proportioning valve recommended.
FSL 120-11125 1.12" .81" Rear Standard piston size supplied with kits. 
Optimal with NA proportioning valve. 
Slightly aggressive bias with turbo proportioning valve.
FNDL 120-11578


Another caliper option is to use the 1.62" calipers in the front, paired with either the 1.38" or the 1.25" in the rear.  The 1.25" piston setup is a bit more conservative than the setup above, but should provide good performance.  It will also reduce overall brake system pressure.  An adjustable proportioning valve is recommended for the 1.38" rear option.  This may also be an option for those who already have a set of calipers they want to use.  Part numbers for this option are listed below.

Alternate Wilwood Calipers
Part # Piston
Position Notes
FSL 120-11133 1.62" 1.25" Front  
FNDL 120-14333
FSL 120-11128 1.38" .81" Rear Adjustable proportioning valve strongly recommended.
FNDL 120-11575
FSL 120-11126 1.25" .81" Rear  


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

Many companies make pads in many different compounds for the Wilwood FSL caliper, including but not limited to: Wilwood, Stoptech, Porterfield, Performance Friction, Hawk, Raybestos, etc.  The Wilwood pad shape for the FSL calipers is #7420, and for the FNDL is #7816.


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 HD Brake Kit

Caliper Clearance Template for Ultralite Brake Kit