High horsepower levels place enormous loads upon the fuel system - to the point where the stock fuel rails and fuel lines are no longer capable of supplying the injectors with adequate fuel at the correct fuel pressure.

This is not only a concern because of the mixture variation from cylinder to cylinder that results, but also because this fuel distribution issue becomes more prominent as the power level increases.

The stock North-South fuel flow configuration however, is an excellent design for the Subaru engine and one that demands further development to satisfy the fuel flow requirements of extreme power engines.

APS has risen to the challenge of delivering the ultimate high performance fuel system - beginning with the awesome APS precision NC machined billet fuel rails.
Huge 7/16 inch internal fuel passages result in extreme fuel flow capacity to each injector - with a significant improvement over stock. In addition, by maintaining a North-South fuel flow configuration, the APS fuel rail solution also solves the distribution problems experienced with after-market Centre-drain designs, where fuel flows past one injector before exiting in the centre of the fuel rail. For fuel to reach the next injector, it must travel down a dead-end passage.

APS fuel rails operate with fresh fuel flow to each and past each injector resulting in the most consistent fuel flow momentum possible to each injector.