Injector Sizing
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
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airfueleddie
- MegaSquirt Newbie
- Posts: 10
- Joined: Sun Jan 20, 2008 7:59 am
Injector Sizing
I am attempting a Flex Fuel system. I have my shortblock completed 4.375X4.15, at 500 cubic inches, V-8, Stroker motor, Edelbrock Single Plane,(MS-II V 3.57 with M.P.I.&1200 CFM 4 hole throttle body) I am having difficulty 'sizing' my Injectors. From the calculators on the MS site I need at least 44 lbs./hr. for gasoline. For E-85 I need at least 70 lbs./hr. how do I find a 'Happy medium' that will allow the use of gas and E-85 without going to 'big' and having low speed driveability/tuning issues? ANY advice will be appreciated! I am sizing my valvetrain for approx 550-600 H.P. NO Racing, just street Hi- performance,,,I also have a 11:2 to 1 Comp ratio with tight quench,(.040) modern closed chambers, alluminum heads with NO sharp edges, if that helps. Thanks
Eddie
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Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: Injector Sizing
Just go with the E85 size - with MS2, you should still have enough pulse width resolution for them on gas.
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devastator
- Experienced Squirter
- Posts: 333
- Joined: Mon Feb 11, 2008 10:19 am
- Location: Kinda near Tucson Arizona
Re: Injector Sizing
When I use the calculator at http://www.megamanual.com/flexfuel.htm, I get 65 as your flow rate for E-85. I would use the larger of the 2 injectors to avoid burning them up. You'll have a little latitude with the fuel pressure and your "low end" should still be tunable.
Sandrail-ACVW 2276 cc, Turbo
MS-II W/spark burning E85
The sand must be punished.
MS-II W/spark burning E85
The sand must be punished.
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airfueleddie
- MegaSquirt Newbie
- Posts: 10
- Joined: Sun Jan 20, 2008 7:59 am
Re: Injector Sizing
Thats what I thought, I just wanted to be sure from you guys.Thanks Devastator and Matt. I'll just order the 65lb./hr. Low Impedance Delphi's from you then Matt. I'm saving up for them now. That should cover the bases and give me enough 'spread' for the H.P. rating I'm targeting, without the problems of heat and PW control. Thanks for timely response,,,Eddie
Eddie