2K4 STI Posted March 4, 2008 Share Posted March 4, 2008 Im collecting the parts for the TD04 swap on my RX.But I cant seem to find when adding a RRFPR what ratio of regulator is needed 1:1 3:1 5:1 7:1 10:1 or 13:1 Any help is appreciated. Thanks Quote Link to comment Share on other sites More sharing options...
Gravityman Posted March 4, 2008 Share Posted March 4, 2008 The problem is it is not an exact science. The only way to really know is to hook up an O2 guage and test with it at different settings. If the engine was already a turbo you should set the boost at the same as stock and slowly work your boost up along with your RRFPR to what ever your desighered boost is. Keep a keen eye on your O2 guage keeping it close to stouich. That should do the trick. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted March 4, 2008 Author Share Posted March 4, 2008 Which FPR do people usually use?Just an adjustable one? or any particular brand? Thanks Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted March 4, 2008 Share Posted March 4, 2008 I don't think there are enough people on this board using RRFPRs to really be about to determine a "most popular brand." I have a Jackson Racing ARRFPR, but haven't installed it yet. It was suggested to me that I remove the factory FPR and replace it with the new one, but it is integrated into the fuel system hard lines. Haven't decided how to get around this problem on my EA81T. Quote Link to comment Share on other sites More sharing options...
john in KY Posted March 4, 2008 Share Posted March 4, 2008 I don't understand your ratios but I ran for years a turbo wagon with 14 pounds of boost using a Mopar RRFPR. Seem to call the Mopar regulator started at 45 pounds and do recall the ratio was 1:1.5. So at full boost the fuel pressure was at 66 pounds. Still have the Mopar boost guage and a new EGT guage I never got around to installing. Also have 6 of the larger 240Z injectors around here somewhere. A 10:1 ratio means to me 10 pounds of boost will increase the fuel pressure by one pound. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted March 5, 2008 Author Share Posted March 5, 2008 So if im running stock boost pressure on my Ea82T but with the TD04 turbo a 1:1 FPR will work fine Quote Link to comment Share on other sites More sharing options...
john in KY Posted March 5, 2008 Share Posted March 5, 2008 No problem with 1:1 at stock boost. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted March 5, 2008 Author Share Posted March 5, 2008 Cool,Thanks Quote Link to comment Share on other sites More sharing options...
merkatroid Posted March 5, 2008 Share Posted March 5, 2008 I ran a Bell engineering rrfpr for awhile on my turboed Impreza. It has a dial that you can adjust to vary the amount of fuel pressure rise. It worked really well to add fuel with minor boost increase. Just my 2 cents Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted March 5, 2008 Author Share Posted March 5, 2008 This is what ive been looking at http://www.vortechsuperchargers.com/product.php?p=31&cat_key=5 Quote Link to comment Share on other sites More sharing options...
Gravityman Posted March 5, 2008 Share Posted March 5, 2008 Ok for every lb of boost the fuel pressure will raise incrementally with it. So, at no boost your F PR should be about 43psi. With a 1:1 ratio the fuel pressure will increase 1 psi per lb of boost. at 1:2 ratio, your fuel pressure will increase 2 psi per pound of boost. And so on and so forth. If you keep the boost at stock levels and the RRFPR at 1:1 then you should have no problems. I built a fuel injector flow bench with my RRFPR. I started flowing injectors with the RRFPR to test a few injector with higher fuel pressures to see what flow rates I could get out of them and if they would work on my ER27TT. I hooked up a boost guage and my air compressor as a source of artificial boost which was regulated with an adjustable air valve. If you dont have yours setup right now, make sure you use your stock FPR inline before your RRFPR in order to keep your stock fuel pressure. Also, make sure your hose clamps are VERY TIGHT! When I jumped the boost, the added fuel pressure started bursting the lines off of the injectors, so make sure all your lines are very tight! You dont want a fire! http://www.ultimatesubaru.org/forum/showthread.php?t=26375&page=7&highlight=flow+bench Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted March 5, 2008 Author Share Posted March 5, 2008 Thanks for the Info GravityMan :banana: Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted March 6, 2008 Share Posted March 6, 2008 If you dont have yours setup right now, make sure you use your stock FPR inline before your RRFPR in order to keep your stock fuel pressure. So we should keep our stock FPR and put the new one in the fuel system after the factory one? Quote Link to comment Share on other sites More sharing options...
Gravityman Posted March 6, 2008 Share Posted March 6, 2008 Correct. The factory will keep the stock fuel pressure and the RRFPR when under boost will basically back up the fuel line causing fuel pressure to increase. The pic I pasted shows how I have it setup. I will draw up the exact fuel flow in the morning for how the flow runs. but basically; fuel pump - filter - injectors - stock regulator - RRFPR - return to surge tank or whatever. The boost or vaccum signal is split 3 ways; one to the boost guage, one to the RRFPR and the other to the stock FPR. Quote Link to comment Share on other sites More sharing options...
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