80LS1T Posted May 5, 2006 Share Posted May 5, 2006 Well this is not Z related but I would rather ask you guys than the morons over on SRTFORUMS.COM. My buddy has a 05' SRT-4 with a big turbo kit on it. We just dyno'd in last Saturday and after seeing the air/fuel ratios we now know that he need a fuel return line. Right when he comes on to boost from about 2500-3200 RPMS it goes nasty lean to about 16:1 but quickly there after drops to 11.7:1 all the way to redline. We tried to richen it up but it wont adjust enough to compensate for that sudden demand of fuel. Apperently the return line and adjustable fuel pressure regulator will solve this problem. The way that these return lines are set up is, the stock regulator on the tank is blocked off, then you T into the supply line and run your regulator to that, then run your return line from the regulator back into your fuel filler neck. My question is how is that different from the stock set up? Basically all you seem to be doing is moving the regulator up inside the engine compartment, right? Can someone explain to me how this set up is different from the stock set up? Guy PS.... the SRT is putting down 374HP/370TQ @ 20psi and 340/336 @17 psi! Yeah his car is fun thats for sure! Quote Link to comment Share on other sites More sharing options...
bjhines Posted May 5, 2006 Share Posted May 5, 2006 in general regulators respond faster/better if you minimize "ballooning" in the lines on the regulated side... this usually means moving it as close to the injectors as possible... and using hard lines for as much as possible... The return might only be used in this case to damp out oscillations in regulated pressure..... there are other benefits to return lines.. but this sounds like it is primarily used as a sort of fuel pressure damper... This assumes your problem is due to a slow responding regulator... It is hard to tell form the description if the regulator is simply bypassing extra fuel or if it is just a calibrated bleed.... In most cases the regulator is in series(inline) with the supply line... If yours is actually parallel(tee'd)... then it must be dumping a fairly large amount of fuel through the return line most of the time... I can't see this as really needing any change in location of the regulator.. because the length of regulated fuel supply line would be the same no matter where you place a regulator if it simply tees off the line(parallel).. in other words... the whole idea of moving it closer to the engine is to minimize ballooning of the lines... but a Tee'd connection will allow the entire length from tank to injectors to balloon and affect the regulated pressure... Check the science behind this fix...It may simply be an easier(accessable) relocation of the regulator... the whole fix may simply be due to a more robust regulator design.. The return line may have less of an impact than simply allowing relocation of the regulator... Quote Link to comment Share on other sites More sharing options...
80LS1T Posted May 6, 2006 Author Share Posted May 6, 2006 When I think of a return line system I think of the regulator being after the fuel rail and then dumping the "extra" fuel back into the tank. The kit that is offered for the SRT-4's doesn't seem to fall into this category. It seems to be just moving the regulator closer to the fuel rail. Maybe the stock regulator is just crap and the new regulator is just that much better at controlling the fuel supply? I think were going to look into a true return line system by either modifying the stock fuel rail by putting a fitting on the other side and then running a new regulator....or, hes going to get and after market fuel rail and run the regulator after the rail. Guy Quote Link to comment Share on other sites More sharing options...
bjhines Posted May 8, 2006 Share Posted May 8, 2006 A consideration popped into mind... The fuel pump may need a lot of bypass flow to stay cool enough... Quote Link to comment Share on other sites More sharing options...
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