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Yes, another injector question.

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Old Nov 10, 2006 | 06:36 AM
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Default Yes, another injector question.

O.k. I'm a tard at best when it comes to injector sizing and tuning so be kind. I'm going FI soon so I'm laying out the fuel system. I've 2 intank pumps, large feed line, return line, rails and regulator already. I'm figuring injector size. On RC site by there calculations running a 650 cc (+-61lb) injector at a base pressure of 60lb and a 1:1 rise on my regulator, with an end pressure of +-74lb, the injector will be suppling in the 850cc range. Using the fuel consumption calc., I need +-850cc to make 800hp. Does this sound right? Now I deffinetly will be going larger than needed for the future needs but I just want to make sure I'm on the right track. Also, which would be easier to tune high z or low?
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Old Nov 10, 2006 | 08:06 AM
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Question It...

Originally Posted by Firechikn
O.k. I'm a tard at best when it comes to injector sizing and tuning so be kind. I'm going FI soon so I'm laying out the fuel system. I've 2 intank pumps, large feed line, return line, rails and regulator already. I'm figuring injector size. On RC site by there calculations running a 650 cc (+-61lb) injector at a base pressure of 60lb and a 1:1 rise on my regulator, with an end pressure of +-74lb, the injector will be suppling in the 850cc range. Using the fuel consumption calc., I need +-850cc to make 800hp. Does this sound right? Now I deffinetly will be going larger than needed for the future needs but I just want to make sure I'm on the right track. Also, which would be easier to tune high z or low?
appears you are looking at a boost of 14#. [60# base, plus the 1:1 reg = 74#].
Since the 14# of boost is also acting on the manifold end of the injector, the net flow will remain at 61#, not 74#.

Is the 800 at the flywheel? [ all HP values should be derived from]

800x .6
______ = 70.58# inj required.
8x .85
Using the 83-85's would allow for future boost increases, and lower duty cycles.

Hi Z injs are not usually found in the higher output sizes, so I'd be looking to find a way to run the low Z units.

Back under my injector bench...

Last edited by Old Geezer; Nov 10, 2006 at 03:42 PM.
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