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View Full Version : Siamese injection?


Wroom
June 26th, 2008, 03:03 PM
I had a thought on saving some pins on an installation of an SM4 controlling a V8. Why not drive the injectors in pairs? A.k.a siamese injection.

If, on a V8 with firing order 1-3-7-2-6-5-4-8, the injectors where wired together like 1+3, 7+2, 6+5 and 4+8, then Injector outputs 5-8 on the SM4 would be free for other use. That's very good, since Inj6-8 can also be used as inputs.

The injectors are 11 Ohm saturated Bosch, so there should be no problem driving them in pair.

That would effectively mean that every second injector is driven 90 degrees earlier. I can't see how that could cause any problems.

Seems like a good strategy. Anyone here that have used siamese injection?
Any opinions or hints about this is much appreciated.

Ian
June 26th, 2008, 11:54 PM
It shouldn't be a problem unless you want to fuel trim individual cylinders. With the early injection on alternate cylinders there may be some slight fuel imbalances but probably no worse than the effects of the wrong exhaust combination that v8 engines have. Unless of course it is a flat plane crank v8 you are talking about.:rolleyes: