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.
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