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Founder, 1929-2014
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Speedway Purple Proportioning Valve

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Outlet Fitting:
1/8" NPT
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Includes (2) 1/8" NPT to 3/8"-24 IFF adapters.
Speedway Purple Proportioning ValveSpeedway Purple Proportioning ValveSpeedway Purple Proportioning Valve
Speedway Purple Proportioning Valve

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Watch the video below to learn more about the differences in brake lines, flare types and fittings you may want to consider before plumbing away on your current chassis project.



Q & A

What's in the Box

Allows easy adjustment of front-to-rear brake bias. Universal design works on all race cars. Has a 100 to 1500 psi range with up to 57 percent pressure reduction.

Includes two 1/8"-27 NPT to 3/8"-24 inverted flare fittings (not pictured).

Brake System Builder's Tip (Link) 

You may also be interested in:

Wilwood 260-8420 Lever Style Proportioning Valve
(Part #8352608420)

This proportioning valve has six preset adjustment points actuated by moving a lever allowing racers to adjust brake bias during a race without having to "look" where the knob position is. This lever "clicks" into the six positions for positive adjustment and the bright red lever is easily seen in a busy racing cockpit. Lever can be rotated 180 degrees for easy installation.

  • This ratchet style brake proportioning valve allows quick and accurate adjustment of brake bias
  • Universal design works on all race cars
  • 100 to 1500 psi range, up to 57% pressure reduction
  • It comes with 6 preset positions, has an aluminum body, rapid ratchet, and positive lock
  • Uses 1/8" NPT fittings

835-2608420 Instructions (PDF)

Wilwood 260-8419 Knob Style Proportioning Valve
(Part #8352608419)

This device lets you adjust the front-to-rear braking balance by proportionally decreasing the rear (or in some cases the front) brake line pressure. Can also be used to adjust individual front wheel braking in dirt track applications. Valve weighs only 5.2 ounces and has two .25" side mounting holes spaced 1.00" apart.

  • Allows easy adjustment of front to rear brake bias
  • Universal design works on all race cars
  • 100 to 1500 psi range, up to 57% pressure reduction
  • Accepts 1/8"-27 NPT fittings

Compensates for weight transfer to the front wheels during braking. All factory brake systems allow for this in some fashion. An APV allows you to "fine tune" a street or race brake system and thus prevents severe rear brake lockup under moderate-to-heavy braking.

835-2608419 Instructions (PDF)

Speedway Polished Proportioning Valve
(Part #91031354)

Allows easy adjustment of front-to-rear brake bias. Universal design works on all race cars. Has a 100 to 1500 psi range with up to 57 percent pressure reduction. Includes two 1/8"-27 NPT to 3/8"-24 inverted flare fittings.

Brake System Builder's Tip (Link)

Wilwood 260-11179 Adjustable Proportioning Block
(Part #83526011179)

This block has the proportioning valve built-in to the rear brake ports and a stop light switch built into the front brake ports. All ports are 3/8"-24 inverted flare female.

  • Compact design simplifies mounting, plumbing, & wiring
  • Maintains full isolation between front and rear fluid circuits
  • Rear circuit has a single inlet and single outlet with the adjustable proportioning valve
  • Front circuit has a single inlet with two outlets

Proportioning Valve Installation Instructions (PDF)

Brake System Builder's Tip (Link)

Detailed Schematic of Proportioning Block 

Learn more about how adjustable proportioning valves work by reading our tech article. Brake System Selection.   

Straight -3 AN Male to 1/8 NPT Male Adapter Fitting
(Part #6174244)

Brake Adaptor.

  • 1/8" NPT


Wilwood 290-0632 570 Brake Fluid, 12 oz Bottle
(Part #8352900632)

Wilwood's specially formulated Hi-Temp 570° Racing Brake Fluid has a minimum 570 degree dry boiling point to withstand the severe heat requirements of automotive racing. Hi-Temp 570's low viscosity allows easy bleeding of your brake system, eliminating aeration of the brake fluid caused by foaming due to excessive pumping of the pedal. 

This high temp brake fluid comes in a convenient 12 ounce container hermetically sealed to guarantee against unwanted absorption of moisture which can drastically lower the fluids boiling point (fluid from larger containers tends to become contaminated with moisture, lowering its boiling point and making it unsuitable for racing applications). 

  • Dry Boiling Point:  573° F
  • Wet Boiling Point:  313° F

8352900632 Instructions (PDF)

AFCO 6691903 Ultra HTX 600+ Brake Fluid, 16.9 oz.
(Part #1066691903)

If you are using a parts store brake fluid, you are not getting the most from your brake system. AFCO Ultra HTX racing brake fluid is specifically formulated for racing under the most demanding conditions. Ultra HTX's high wet and dry boiling points give you maximum protection against vapor lock and other problems associated with high brake system temperatures. With a 600+ degree boiling point, Ultra HTX high temp brake fluid sets a new standard for brake fluid performance.

  • Specifically formulated for racing
  • High wet and dry boiling points
  • 600+ degree dry boiling point
  • Exceeds D.O.T. 3, 4 and 5.1 requirements
  • Virtually elminates vapor lock
  • Non-silicone