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| The WORKS Aperture II throttle body is a modifed stock throttle body with special high pressure shaft seals and a 65mm throttle plate. |
First we reinstalled our XS Engineering Intercooler which we talked about in part two of our series. As we had run out of injector in part two we also upgraded our injectors to RC Engineering 1000cc injectors. We chose a big injector so we would not have to mess with injectors again. Come more radical mods, E85 fuel or whatever, we would have enough injector for anything we plan to do to the car.
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| The larger size of the WORKS Aperture II throttle body is easier to see from the back. |
Big injectors often idle poorly. As injector size increase, the amount of pulse width to feed fuel at idle and part throttle becomes very short, so short that the duty cycle can become shorter than the invalid time which is the amount of time it takes the injector to open and close. At this point it is hard for the ECU to control the mixture. At super low duty cycles, the injector can also drip instead of spray giving poor atomization. These things can cause rough idle and poor driveability.
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| Technosqaure’s Howard Watanabe ports out our intake manifold to match the WORKS throttle body. |
We selected the RC injectors because they use a deflected disc nozzle which uses a ball pushing on a disc to meter the fuel instead of a pintle and valve seat like a conventional injector. Deflected disc injectors have a better and more stable spray pattern at low duty cycles. They are also less sensitive to clogging. We were confident that the RC injectors could deliver the fuel we needed and still idle fine.
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| Quite a bit of material had to be removed. |
