Raceonly Billet AST Delete kit for FD3S RX7 – Gen2


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The Raceonly Expansion Tank is designed to eliminate the OEM & other aftermarket AST (air separator tank) on the 93+ Mazda FD3S RX-7. Designed in-house by the Raceonly team, our expansion tank supersedes all other remote mount AST layouts with superior overall design & craftsmanship. More efficient coolant/water transfer & air separation makes it perfect for both street & race, as well as less headaches and failure points. See full features.

The biggest 2 changes with our Gen 2 AST Delete is the addition of an AN-16 fitting for those who want to run braided hose. No this does NOT STOP you from running the OEM radiator hose as well. The choice is yours.

We have also reduced the diameter of the flange by 2mm which allows for slightly a larger turbo to sit next to it.

Our unit allows a G42-1450 to fit right next to the AST with our twingate turblown manifold.

32 in stock (can be backordered)


Ast Kit Delete

Key Features

  • Made in Australia.
  • Replaces both the factory thermostat housing/water neck & the air separator tank.
  • Made entirely of aircraft grade billet 6061 aluminum, precision machined
  • Simple, 100% direct bolt-on.
  • Works w/ the factory metric thread water level sensor, overflow tank, large & the small radiator hoses & factory AST cap.
  • Reduces unnecessary weight & eliminates all the extra small hose nonsense.
  • No longer have to worry about the Plastic AST bottle exploding and destroying your engine.
  • Compact design allows added clearance for large turbochargers & aggressive turbo placement.
  • Compatible with Sequential Twin turbo FD and Single Turbo FD RX7.
  • Fits all FD RX7’s from 93-2002
  • Works with large water pump underdrive & idler pulleys.
  • Black powder coated finish
  • Increased water transfer & air separation.
  • Now has AN16 Fitting in built as well as OEM radiator hose support both in 1

What’s Included?

  • M6X20Mm Stainless Bolts X3
  • Dash 6 ORB Male AN Adaptor
  • 9o Degree Push Lock 3/8 Barb Fitting
  • Spring Clamp for Overflow Bottle Hose

Additional information

Weight 3 kg
Dimensions 30 × 30 × 30 cm