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Discussion Starter · #1 ·
thinking of upgrading my fuel injectors to 680CC. what kind of electronics would I need to get to make it run right?

also, would it be cheaper to go with additional injectors? if so, what kind of electronic do I need to get with additional injectors?


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As of right now, you'd need a VPC and a fuel controller (SFC, AFC, GCC, etc.). With the AEM unit supposedly coming out soon, I'd recommend waiting to see what that thing actually does. If it's somewhat as good as they claim, that would be the way to do -- forget all the 3-letter piggy-backs.

The dual-injector systems in theory are good because they allow you to operate on a smallish first stage injector for excellent atomization and throttle response at low RPM, then bring in the reserves for the heavy hitting. But, I don't know how well they work in reality. Hardly anyone uses them on the Supra. The dual system would probably be more expensive because you'd have to have the additional injector mounts installed in the manifold.

But IMO, there's not really a need for the dual-injector system. If everything is working properly with the 680/720/750 cc size injectors and a VPC, idle, throttle response, and low-RPM drivability is as good as stock so long as you're on the stock cams. At least it was with my car. Once you switch to larger cams the idle quality may deterioriate ever so slightly, but not to the extent that it's a problem.

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