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Hi guys,

what are the benefits of using 4 injector per throttle body? I saw a picture of the Holzapfel Overfly enigne that uses this setup. Since the TBs are not that much more expensive I am considering it if it has benefits and if the Autronic SMC supports it. I do not even now if the management system has to support it since they inject at the same time per cylinder (I guess).
My logic and research tells me that I can use smaller injectors and I would get a better fuel filling with dual injectors per cylinder.

Is this true and what are your thoughts on this.
I am going to use dual IDF TBs no matter what. Looks better with the 911 shroud and I do not have to fab anything.

Thanks so much again,

Alex

One thing that many injectors will do is dweliver a LOT of fuel.

Another is, if they are "staged," at low RPM only 1 per cylidner fires, giving you much better metering ability. That way at low RPM cruise, for example, 4 injectors can run at 25% cycle while the rest are off, where if you had only 4 large injetors that ran all the time they'd have to run at 12%, which might hurt efficiency and drivability.

Staging is common, desirable, and effective.

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*** Teach a Man to Fish ***
Searoy

"I tend to lean toward a tighter gap and a
looser skirt....a little slap never hurt." -- Joe of the West

Hello-

I wouldn't mess with it. For a normally-aspirated engine of your size, approximate power, and a rising-rate pressure regulator, 30 lb/hr. injectors will run a peak of 90-95% duty. At idle, they still use about 3% duty. Rule of thumb says that idle quality doesn't begin to suck until about 1-1.5% at idle.

Take care,

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Shad Laws
LN Engineering
http://www.lnengineering.com