Canadianz Posted February 10, 2008 Share Posted February 10, 2008 Hey Guys, Ive got some questions concerning the fuel rail on the RB and need input. As it stands right now I am using an aftermarket areomotive adjustable fuel pressure reg. The problem is the stock rail has a regulator bolted on from the factory. The stock regulator looks like this. . . You can buy a fitting like this to replace the regulator to accept AN lines, like this, the kicker is they cost around 50-80$ My question is, is it smarter to buy the adapter, or go and buy a whole new rail designed for side feeds? I am using stock injectors and the stock computer with low boost, with the intent to keep things stock for a year or so till I can afford an ECU and injectors. My other thought is that if the stock rail flows enough I could just stay with it and some side feeds, using the adapter and removing the nissan FPR. Any thoughts ?? Quote Link to comment Share on other sites More sharing options...
Careless Posted February 10, 2008 Share Posted February 10, 2008 well fuel rails cost about 200. I think if you intend to keep it relatively stock or about 400 or so hp, you wouldn't need a 200 dollar fuel rail, and the 50 dollar fitting could save you 150+ dollars for something else to GET you to the 400hp mark. no? im using 400hp as a baseline for what ppl say most of the stock RB26 parts are reliable at before any need changing. Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted February 11, 2008 Share Posted February 11, 2008 Rb25det's run side feed injectors from the factory. You can buy other aftermarket side feed injectors up to 880cc that will slide right into the rb25det fuel rails. Most aftermarket fuel rails will use a 11mm top feed injector design. As Raff said, you can get close to 400hp out of the stock rb26 fuel system. For 6 cylinder applications what I normally do to estimate for hp is.... The number of CC's the injectors are will be close to the hp you will be able to run safely. So 370cc ~ 370hp. Get what I am saying? Quote Link to comment Share on other sites More sharing options...
Canadianz Posted February 12, 2008 Author Share Posted February 12, 2008 I think that makes sense what you guys are saying. I knew the 25's use side feeds, thats nice to know they do go that high in flow. Im going to order that little fitting tonight and get it over with. In theory is the RB25 stock rail a restriction ? Or is the only reason to switch the ability to use top feeds ? Any how thanks guys for the feed back, its appreciated! Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted February 12, 2008 Share Posted February 12, 2008 I dont think the stock rb25det fuel rail is a restriction, until you get into 700whp+ territory. Which I dont think I have ever seen a rb25 put that much power down. (Moot Point). The only reason to go top feed is to get bigger injectors IMO. Also the top feed inj. are easier to find/replace. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted February 12, 2008 Share Posted February 12, 2008 I have a pallnet top feed RB25 rail for sale if anyone wants it. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted February 21, 2008 Share Posted February 21, 2008 I have a pallnet top feed RB25 rail for sale if anyone wants it. Sold Quote Link to comment Share on other sites More sharing options...
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