Fueling & Injection Fuel Pumps | Injectors | Rails | Regulators | Tanks

Fuel rail ends -6 or -8??

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Old Dec 4, 2008 | 08:26 PM
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Default Fuel rail ends -6 or -8??

Looking at getting some fittings ordered for another project and thought I would order my fuel rail fittings as well. What size are you guys running? All the aftermarket rails are for 3/8 I just need to know 3/8 to 6 or 8 for the fuel line in and also for the crossover line. If I am thinking correct it is -8 for the in line and -6 for a crossover line or does it even matter?? Thanks guys. Also, if it matters I will be using the aftermarket quick connect to factory feed line.
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Old Dec 4, 2008 | 08:34 PM
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I did -8 fittings in mine, also you should do a -8 crossover and then the final outlet to your return line/regulator can be a -6!
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Old Dec 4, 2008 | 08:35 PM
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-8an into the rails, -8an for the crossover and -8an into the regulator if rail mounted, 6an out of the regulator to the tank is how I have mine set up.
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Old Dec 4, 2008 | 08:56 PM
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I am not using a regulator and my car does not have a return line just 1 feed line from the factory that way?? so I can just block the passenger front off with a 3/8 npt plug correct? Thanks guys.
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Old Dec 5, 2008 | 07:45 AM
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Yes, you can do it that way, but a front mounted regulator with a dedicated return line is preferable.

If you run a new -8an line from the tank to the fuel rails, you can use the factory feed as the return.
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Old Dec 5, 2008 | 08:53 AM
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Originally Posted by ss1
Yes, you can do it that way, but a front mounted regulator with a dedicated return line is preferable.
Why is that?
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Old Dec 5, 2008 | 09:02 AM
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In case there is a pressure drop across the rails, you place the regulator after them. This way, each injector is assured it will have proper fuel pressure.
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Old Dec 5, 2008 | 09:07 AM
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So you would change out the returnless system on vettes or 99+ f-body's and trucks, etc.?
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Old Dec 5, 2008 | 10:08 AM
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I'd swap it out in high power applications. Right now I'm over 500rwhp on the stock system with a Racetronix pump. Currently working on the Lonnies/Racetronix double pump setup with -8an feed line and return type regulator using the stock feed as the return line.

Sorry if I came across like I was saying all cars should be done this way. I just assumed if people are running aftermarket rails they are shooting for big numbers, and forgot about the bling factor.
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Old Dec 5, 2008 | 10:11 AM
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Just asking. I wouldn't make the switch either unless the application was way up ther in power.
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Old Dec 5, 2008 | 10:13 AM
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Not a bling factor in my case but also not real big power. Going NA but if I get the Fast intake or Fibertuned intake I will not use the factory rails due to I sold them with the L76 intake so I need new rails regardless and just want to know what needs to be done. Would you use a -6 feed in any case or use all -8's? Thanks for the help it is very useful.
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Old Dec 5, 2008 | 10:15 AM
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Also be careful not all rails are 3/8" pipe some rails are -8 into the rail like ours. And if using the factory feed -6 is more then enough. Depending on your power level you do not need to go to a return line setup.

Nate
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Old Dec 5, 2008 | 10:21 AM
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That was my other question, on the aftermarket lines that allow you to attach the factory feed line via quick connect to the rails isn't that a -6? If so I would need to use all -6. Thanks again.
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