Mitsubishi EVO IX - Deliver Us From EVO

Injector Duty CycleInjector duty cycle refers to the amount of time the injector stays open. Injectors are efficient up to 85 percent on Pintle type (found on EVO's) while the "Disc type," which RC Engineering distributes and sells, can handle up to 90 percent before the injector begins to lock up. Injectors are electric solenoids that can overheat and malfunction when running above the accepted standard of 80-90 percent duty cycle. During high injector duty cycles, the electronic signal that the injector receives can "step" on itself; given that a fuel injector is a mechanical device (needing time to open and close), it is easily possible that the injector could be on its closing stroke by the time another "open" command comes from the ECU. What you're stuck with is a "stuttering" injector that never really opens or closes completely, dramatically reducing fuel flow and ultimately leading to lean mixtures that produce the perfect recipe for blown engines. This extremely dangerous situation will usually occur at the worst of times, full throttle at max boost-or high RPM-just when you need 100 percent fuel delivery, you get 50 percent and go dead-lean.

RC states MSRP listing on either injector size is $98.75 a piece. If either the 750cc or 1000cc injectors don't seem to fit your requisition, RC Engineering can custom build any size injector to suit your vehicles needs. So next time you plan on building your EVO to deliver neck snapping performance, consider the importance of upgrading those injectors.

RC Engineering displays both preliminary numbers and after servicing injector statistics. Notice injector number three and four fall below the rated 550cc flow rate.