Fuel and Ignition Fuel Pumps and Systems, Ignition and Spark Systems

42# Injectors

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Old Jan 27, 2010 | 09:58 AM
  #1  
manfire1987's Avatar
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Cool 42# Injectors

I ordered 42# lucas injectors.. Will these work ok with stock fuel pump and all that and are those injectors to big for what i am going to be running in my signature check it out let me know.. lot of people said 39# svo injectors so when purchasing the 42# figured no big deal now I want to make sure thanks let me know..
Old Jan 27, 2010 | 03:30 PM
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Multiply the expected flywheel HP (NA) by 0.07 to get the minimum injector size. 500HP needs at least 35 #/HR. 42's are good for 600 HP at the flywheel.

But the injectors will only flow the amount of fuel the engine needs, so the fuel pump size should be based on flywheel HP as well, not the size of the injectors.
Old Jan 28, 2010 | 05:36 AM
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My goal is 400 rwhp. With the cam and heads and all bolt ons should be close what hp at flywheel you think that will be
Old Jan 28, 2010 | 11:24 AM
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From: Hell was full so they sent me to NJ
If your goal is 400rwHP, through your T56, my estimate of your flywheel HP would be:

400rwHP / (0.87) = 460 flywheel HP

460 x 0.07 = 32.2 #/HR

Whether you make 460 HP at the flywheel will depend on the details of the heads, the cam, the intake, the exhaust, etc. LLoyd's side says 370-410rwHP, depending on the cam selection.

Assuming a 25% return rate, at 460 flywheel HP you need about 185 LPH. I don't know what the flow rating of the stock fuel pump is.

Last edited by Injuneer; Jan 28, 2010 at 11:26 AM.
Old Jan 28, 2010 | 11:36 AM
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Llyod suggested 39lb svo injector.. sounds silly but wanted nothing to do with ford parts in my camaro lol getting the good deal I did on the lucas 42lb I went for them assuming 3lbs was not a huge difference.. sounds like either way there to big?? Wat happens with to big of an injector? I was under the impression if I make 400rwhp motor itself is putting out a a lot more... also what is LPH?? Thanks much for all your help.. I am 22 years old and got a lot to learn and I am building my drag/strip dream car ;-) its turned out to be a lot harder than I thought
Old Jan 28, 2010 | 11:48 AM
  #6  
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From what I can find stock 96 fuel pump is 190 LPH at 43 psi not sure how accurate this information it is put found it on two seperate websites..
Old Jan 28, 2010 | 05:28 PM
  #7  
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There's no problem with running the 42's. Past experience indicates the stock PCM can achieve the required short pulse widths required for idle, with the 42# injectors.

Ford injectors aren't made by Ford... they are Bosch and Denso pintle style injectors.

I've measured the drivetrain losses on my 94, with the T56, McLeod Street Twin with steel flywheel, and 12-bolt rear. At 486 flywheel HP, the drivetrain losses were about 12.4%, netting 426HP at the rear wheels. That's why I used 0.87 to calculate your flywheel HP.
Old Jan 29, 2010 | 01:30 AM
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You seem to really know your stuff... well ill use the 42lb and hope for the best.. I can't wait to have this build done
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