motoman Posted January 4, 2011 Share Posted January 4, 2011 (edited) Before i get to far into creating this fuel system i would like to know if it will be functional. The feed lines from the fuel tank all the way to the fuel rail are an-8. After the fuel rail the line reduces in size to an an-6. The lines going to and from the vapor tank will be rubber. This is for a Rb25det that I'm later planning on making around 400-500 hp. Here is a quick sketch of my idea. Edited January 4, 2011 by motoman Quote Link to comment Share on other sites More sharing options...
johnc Posted January 4, 2011 Share Posted January 4, 2011 Before i get to far into creating this fuel system i would like to know if it will be functional. The feed lines from the fuel tank all the way to the fuel rail are an-8. After the fuel rail the line reduces in size to an an-6. The lines going to and from the vapor tank will be rubber. This is for a Rb25det that I'm later planning on making around 400-500 hp. Here is a quick sketch of my idea. The return comes off the FPR. The fuel rail can be dead headed. Quote Link to comment Share on other sites More sharing options...
bjhines Posted January 4, 2011 Share Posted January 4, 2011 or place the FPR after the rail with the return directly to the tank. This depends on the FPR you choose. Quote Link to comment Share on other sites More sharing options...
motoman Posted January 4, 2011 Author Share Posted January 4, 2011 (edited) The FPR is only a single port return, I know you two both know far more then me in this area, but why should the FPR be placed after the fuel rail? After rereading your post JohnC i think i get what you mean. This is what it should look like right. Edited January 4, 2011 by motoman Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 4, 2011 Share Posted January 4, 2011 Option 2. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 4, 2011 Share Posted January 4, 2011 The FPR placed after the rail puts the pumps FULL CAPACITY available to the injectors, and regulates pressure on a 'backpressure basis'... If you place it before the rail, you use the FPR to restrict the flow and dump excess fuel before it ever has a chance to feed the injectors. If there is something untoward that happens the FPR is a potential bottleneck to the pumps flow to the injectors. Also, putting it as a backpressure regulator lets the pump operate at an amperage which can potentially be lower. This was discussed in the past. In detail. If you look at the stock systems, the FPR is almost always after the injectors at the end of the fuel rail. It aids in bleeding air, and helps in Vapor Suppression. My concern is 'what tank' are you planning on using, and where is the surge/swirl pot to ensure a flooded pump inlet at all times? Quote Link to comment Share on other sites More sharing options...
Wedge Posted January 22, 2011 Share Posted January 22, 2011 Very interessted in this discussion since i was going to ask a similar question. Quote Link to comment Share on other sites More sharing options...
SypherSlayer Posted April 1, 2011 Share Posted April 1, 2011 I'm about to start a similar build with an rb25det but my goal is a bit less in the 350-400hp range later down the road. I know that i'll need a surge tank due to the carb set-up. with that said i was wondering if this set up would work for my 72Z? also what size lines do you guys think i should run? thanks Quote Link to comment Share on other sites More sharing options...
lowrider Posted April 1, 2011 Share Posted April 1, 2011 I'm about to start a similar build with an rb25det but my goal is a bit less in the 350-400hp range later down the road. I know that i'll need a surge tank due to the carb set-up. with that said i was wondering if this set up would work for my 72Z? also what size lines do you guys think i should run? thanks The return from the fuel pressure regulator needs to go back to the surge tank, then a line on the top of the surge tank goes back to the fuel tank, for over-flow. Like so: I neglected to include filters before the fuel pumps, but the lines are correct. Quote Link to comment Share on other sites More sharing options...
SypherSlayer Posted April 5, 2011 Share Posted April 5, 2011 Awesome drawing. Helps a ton. Pictures say a 1000 words. Thanks for the help Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted April 6, 2011 Share Posted April 6, 2011 would a check valve on the overflow tube be a good idea? Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted April 14, 2011 Share Posted April 14, 2011 I'm also wondering about check valves, but on the return from the fuel rail more so than the return to the tank. I have a 5/16 line feeding the surge tank and a 5/16 return from the surge tank, and then I have a 3/8 feed to the injectors and a 3/8 return from the injectors to the surge tank... I am wondering if maybe fuel is wanting to flow up into my return line from the injectors into the bottom of my pressure regulator instead of into my 5/16 return to the tank... Perhaps this would explain why I can't adjust my Fuel pressure below 60PSI... Quote Link to comment Share on other sites More sharing options...
Texlenin Posted July 6, 2011 Share Posted July 6, 2011 @Tony D : I have searched for the post regarding "deadheading" aftermarket rails, and have never seemed to locate it. Any way you could point me in the right direction? I installed an ebay one-off fuel rail(approx 23mm OD) in the following manner: stock filter==2 port(stock)FPR (in on side, out on bottom, per FSM)====rear of new rail. Return line blocked off. It doesn't seem to like that very much, but several other problems could also be influencing that. Would it not be more important to meter the fuel going into the rail, as opposed to trying to control it on the far end? Hopelessly clueless as usual.... Quote Link to comment Share on other sites More sharing options...
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