Robert Posted August 20, 2009 Share Posted August 20, 2009 Hi, I have a L24E that Ive turbocharged and Megasquirted with 440cc supra injectors. I do have a problem though, cause at what I think feels like about 300BHP, maybee a little more, the injectors are maxed out, and the engine screems for more fuel!! Has anyone done 300+ BHP on stock fuel rail before? My setup: L24E stock internals T04E turbo .63 exhaust 3" exhaust Intercooler Stock fuel rail 440CC injectors - Should support 400+hp Walbro Fuel pump Stock fuel pressure regulator (should be 1:1) Megasquirt 100% DC @ 5000+RPM Approx 300BHP Quote Link to comment Share on other sites More sharing options...
1 fast z Posted August 20, 2009 Share Posted August 20, 2009 Put a fuel pressure guage before the rail. If it is the rail (more than likely not) then you will see a huge fuel PSI before the rail. Then put the guage in the rail, and compare. Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted August 20, 2009 Share Posted August 20, 2009 Perhaps a rising rate fuel pressure regulator would prevent the engine from leaning out if that is the case. Quote Link to comment Share on other sites More sharing options...
jc052685 Posted August 20, 2009 Share Posted August 20, 2009 Stock fuel rail should be good for over 400hp. Even more if itst an early dual feed. Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted August 20, 2009 Share Posted August 20, 2009 Can someone explain how you can use Supra 440 injectors with a stock fuel rail because they are "O" ringed and not barbed like stock? Quote Link to comment Share on other sites More sharing options...
kolonelklink87 Posted August 20, 2009 Share Posted August 20, 2009 it is possible to fit and clamp some EFI hose over the back of some o-ring injectors. Many members have done it (inc. myself) although it is not exactly the recommended approach. Quote Link to comment Share on other sites More sharing options...
jc052685 Posted August 21, 2009 Share Posted August 21, 2009 That is what I am doing Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted August 21, 2009 Share Posted August 21, 2009 Don't forget that the stock FPR is set to ~38 psi instead of the 43 that is the norm - this will increse the duty cycle and lower the output of the injectors... Quote Link to comment Share on other sites More sharing options...
Robert Posted August 21, 2009 Author Share Posted August 21, 2009 Hi. Such small pressure drops should not lower the injectors to much, but lets say 400cc.. This still gives me an extremely high BSFC if my "seat of pants" ~300 BHP is correct. I could do a drag with a 300BHP car just to test though. I did some diagnosis last night. I changed my fuel filter so theres no braking there, and I clamped the fuel return pipe on the rail to increase fuel pressure. Im going to take it for a test drive today and see if I can lower the dutycycles a little now. Ive also E-mailed Topendperformance, and they, like you, claimed the stock rail handles 350hp easy. My only conclusion is that either the pressure regulator dont raise the pressure enough, or my walbro pump cant handle the demands. Thanks Quote Link to comment Share on other sites More sharing options...
Robert Posted August 21, 2009 Author Share Posted August 21, 2009 Put a fuel pressure guage before the rail. If it is the rail (more than likely not) then you will see a huge fuel PSI before the rail. Then put the guage in the rail, and compare. Ill try to get a gauge that I can hold up to the windscreen. That way I can see If the pressure drops at high RPMs. If so, the pump probably needs to be replaced... Quote Link to comment Share on other sites More sharing options...
1 fast z Posted August 21, 2009 Share Posted August 21, 2009 I went through 4 Walbro 255's HP. I will never buy another. They are junk IMHO. Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 21, 2009 Share Posted August 21, 2009 The clamp idea makes me cringe for o-ring injectors. The proper way is to use a billet fuel rail that has 11mm bores for the orings to seat into. Quote Link to comment Share on other sites More sharing options...
Robert Posted August 21, 2009 Author Share Posted August 21, 2009 I went through 4 Walbro 255's HP. I will never buy another. They are junk IMHO. ? Its my third 255, never had any issues, until maybe now! Quote Link to comment Share on other sites More sharing options...
JIM73240Z Posted August 21, 2009 Share Posted August 21, 2009 There are several members that have over 400 rwhp with the stock fuel lines and rail. Cliftons race car being one of them. They do not look as good as a pallnet but they do the job. jimbo Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted August 22, 2009 Share Posted August 22, 2009 I went through 4 Walbro 255's HP. I will never buy another. They are junk IMHO. What pump do you endorse? Quote Link to comment Share on other sites More sharing options...
Robert Posted August 22, 2009 Author Share Posted August 22, 2009 A little update here: I replaced my fuel filter, and clamped the fuel return pipe a little (to increase the base pressure in the rail). Also i opened up the "IN" pipe where the hose is clamped on, cause theres a smaller diameter on the pipe there. So, I took it for a drive, and the first thing I noticed was that It was close to impossible to start! Good sign.. Further on the AF ratio was a bit richer than normal, about 0.5-1 AF value lower I would guess. Unfortionatly my computer was not in the car, so I had no possibility to tune it, but I emptied a few gears, and the AFs, that earlier went up to 13s on 5000+ was now down on 10s! Now I dont know how much extra pressure Ive applied here, but the injector CCs dont grow too much on higher pressure.. Also the fuel filter could have been clogged a little, and the narrowing on the "in" pipe probably restricted flow a little. All in all, I think I got a little here and a little there. Im going to tune it tonight and hope to get the DC down to 80s, or at least 90s.... Quote Link to comment Share on other sites More sharing options...
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