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Staged Sequential injection?

EFI Tuning Fundamentals

Discussion and questions related to the course EFI Tuning Fundamentals


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Thanks for an awesome course so far!

I'll be using a Syvecs s6+ on a 6 cylinder, I am undecided on the injection system of 6 or 12 injectors. I was wondering is it possible to run 12 injectors, Staged, but still sequentially? Or are your options one or the other?

Looking at the spec for the ECU, can't see why not -

"16 x Low Side Injection/PWM Outputs (Max 10 Amps)"

My own experience of staged sequential injection was on a 9500+RPM Toyota 4AGE race engine. The lower flow lower injectors were in the head, the much higher flow uppers outside the trumpets. This was on Pectel T6, so not a million miles from your Syvecs.

We have have better idle, starting and drivability round the paddock, combined with about 5-7BHP at the top end AND better torque. Throttle response was also improved...didn't feel like it had an elastic throttle cable. It made the car much nicer to live with even if the lap times weren't significantly improved. It also destroyed fewer spark plugs and probably paid for itself in the long run.

I have reserved six outputs for my V6 (Nissan VQ30DE with Motec M1) to do the same once it is up and running. For the cost of six injectors, a fuel rail, some pipework and some plugs it seems silly NOT to give it a go! Particularly on the V6 the car needs to pass an emissions test so idle fueling is going to be crucial, the smaller the lower injector and the closer to the valves the better!

Thanks Denis

It is dependent on what you're trying to achieve. It's not uncommon in high output N/A engines to run a set of primary injectors down by the intake valve which works well at low rpm and low load. Often a second set of injectors are located outside the inlet trumpets for use at high rpm/load and this can offer improved atomistation and a more homogenous fuel/air mix. This can provide a small but real gain in power. Of course the other option is to use staged injection when it's hard to provide sufficient fuel for the engine through a single set of injectors.