Which 42lb injectors to get..?

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12-08-2012, 01:49 PM

#16

993turbo

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I see no issue running a 42lb injector of modern design. They should ''vapourize'' the fuel pretty well. A 42lb injector is not as large as the ''Green Giant'' name might suggest. In European 4 and 5 cyl engine tuning we use injectors twice this size.

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12-08-2012, 01:54 PM

#17

993turbo

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Quote:

Originally Posted by dprantl

Although I have a custom intake manifold, I am pretty sure that these injectors do not require any modification to fit the stock fuel rails and clips and are direct drop-ins.

I am seeing just over 70% duty cycle on the green giants at 6,700RPM. It has been a few years and a bunch of changes since I dynoed at 475hp (406rwhp) so I am probably closer to ~510hp now. I am currently running an Eaton M112 which is most probably less efficient than a centrifugal compressor that you plan to run.

Dan
'91 928GT S/C

475hp/460lb.ft

Cool, that sounds about right. Im planning to go closer to around 550hp on the GT engine, and expect around 80% duty cycle on the ''green giants''.

In my calculation the 36lb would be maxed out. I do not wanna run a maxed out injector at the top risking a lean mixture......

Are you using a Std. MAF, or a Supermaf with your output?

Quote:

Originally Posted by ptuomov

I have sixty pounders and they work just fine for me. The injectors were sourced by John Kuhn. We talked about it, and flow matching is not a terribly relevant thing with the stock manifold and batch fire system. With this intake manifold, you're never going to be that close to balanced.

Thanks for the input, so 2-3% should right on the ball for the injectors.

Quote:

Originally Posted by atb

Are you running all of the stock dampers? I'm surprised to hear this.

I am currently running the Stock Regualtor and the two dampers. Ive been thinking about removing the 2 dampers. Any benefit from this?

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12-08-2012, 02:08 PM

#18

dprantl

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I am running a SuperMAF. I was maxing out the standard MAF. I am also running the stock fuel rails with both dampers and stock regulator. I didn't see any reason to remove the dampers, and figured there must be some kind of reason why Porsche put them there. I also have a Bosch 044 fuel pump with Tim Murphy's stainless strainer and the in-tank pump removed.

Dan
'91 928GT S/C

475hp/460lb.ft

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12-08-2012, 04:00 PM

#19

Speedtoys

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Im running -1- damper on the Victor SC setup. Which is the core problem...one damper.

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12-08-2012, 10:47 PM

#20

993turbo

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Quote:

Originally Posted by dprantl

475hp/460lb.ft

Ive removed the intank pump and I have the 044 pump as well.

Quote:

Originally Posted by Speedtoys

Im running -1- damper on the Victor SC setup. Which is the core problem...one damper.

I will try to maintain both dampers then. On the other hand, Ive heard many who has removed both dampers without issues.

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12-09-2012, 02:16 AM

#21

jorj7

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I'm running without dampers on my car, 52lb RC Engineering fuel injectors and 55 psi fuel pressure (at 0"), 2 Bosch 044 fuel pumps and
15 psi max boost. Ran pretty well this season. Of course it took Bill and I a while to get it tuned and running this well.