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batch/sequential fire injectors


Guest De Schmaydee

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Guest De Schmaydee

...is one better than the other?...its my understanding that the stock injectors batchfire,..i'm adding 6 more injectors (about 1 1/2" upstream on the manifold)that will be independently controlled (sequentially)....i was wondering if it might not be better to put the sequentially fired injectors where the original injectors were....and the batchfired injectors 1 1/2" back on the manifold....or will it make any difference.....s

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WOT you're spraying on the backs of the intake valves anyway. Sequential is best for emissions and idle quality but for ultimate power there's little difference between batch and sequential.

 

In your case - how will you time the injectors and do you really need as many as six?! That's a bunch of fuel unless those are tiny injectors - how will you control the other injectors?

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Popular theory is that at RPMs above idle it's nearly pointless to sequentially fire injectors. Think how fast the injectors would be firing, and how fast the valves would be opening and shutting.

 

Sequential firing makes the computer think too much. At idle, seq. fire helps to maintain a very stable idle, but at any engine speed above that, batch fire works the same. There's a steady mist, basically, of fuel in the intake runners, something that can be acomplished simply enough by batchfire.

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In fact there comes a point where the injector open time is GREATER than valve open time! The Supra is like this - I'm controlling injector phasing and in the upper loadRPM regions I have to fire on the closed valve and continue firing as it opens in order to get the fuel in there! Batch works just fine in cases like that IMO.

 

Given a choice between batch, bank, and sequential I'd go sequential first, bank second, batch last. I think bank fire is a decent compromise (shrug).

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Guest De Schmaydee

...i'm using an hks aic3 si injector controller.....it controls up to 8 additional injectors independent of the stock ecu...

....the stock ecu controls the original 6 (same as always)....the aic will compute how to do its inj's based on the boost/rpm curves (and the info i have programmed into it).....supposedly...

...i'm going to use stock inj's for the second 6....everybody is putting in big ones and selling their old (stock) ones cheap ($10ea)...i can also use the stock regulator/s for the 2 rails and just have to upgrade my pump......the 2nd 6 will be about 1.5" upstream of the old ones on the intake(there's a pict of it in maximum boost). on a second rail

...havent put it on yet, begi has just now begun making the modifications to my intake/exhaust manifolds......'sposed to have 'em back w/in 10 days or so......s

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