dynoed today..need bigger injectors...
Thread Starter
Joined: Apr 2005
Posts: 1,014
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From: san marcos, TX
dynoed today..need bigger injectors... I just got back from the dyno. I have 60lb injectors and they hit 100% duty cycle at 5200rpm 62psi of fuel pressure and 15psi boost...No meth, held 12.1 AFR all the way to about 4500rpm then went lean, 16 degs timming...Weird...Tuner says I need 75lb injectors... Dynoed 630rwhp 646rwtq at 5200rpm... Where"s the best place to get 75lb injectors??
what are you running for a fuel pump? I would agree with the tuner myself on this one and go for bigger injectors. If he is good he can tune it so its not pig rich and that way to don't have to run crazy fuel pressures then have to worry about not having enough pump to support the flow at those pressures. I am not a believer of running fuel pressures past 65psi at max boost after that I have seen issues with atomization and injector flows
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You should not be out of injector... I made 600rwhp at 10psi with those but run 16psi daily, and I have had it up as high as 19psi and still kept the AFRs to about 10.9:1. Mightymouse made 852rwhp with 60s... Maybe you just need a boost referenced fuel system and/or more pump.
Thread Starter
Joined: Apr 2005
Posts: 1,014
Likes: 0
From: san marcos, TX
factory lines are 3/8" or -6an size...good for up to 900rwhp or so. a local Z06 is running a 402ls2 and the Paxton making 880rwhp through the factory fuel lines..
here's my engine..
here's my engine..
stock lines are good to about 650rwhp but need a return for boost reference. You can get away with a bigger feedline and using the stock feed for a return or can even do it a cheaper way if you don't plan on going to extreme. That using you stock feedline as the feedline and your evap line for the return, but you do need a return none the less. This insures the right pressure having the reg downstream of the rails. Sounds like you should have enough pressure from that pump depends on the wiring and fuel line plumbing. Maybe try a bigger external pump, go dual intank pumps or get a boost a pump. The 60# are good for allot of power and the next step up start to get pretty extreme. I'd trouble shoot and look elsewhere before going with bigger injectors. Good luck.
Its Funny I have a buddy with a problem just like this. He gets to around 620rwhp and runs out of fuel. He has no fixed the problem but he always thought it was the lines. He has duel intank 255s. and 60lbs. I wonder if just buying one of those fuel systems from ls1speed of TR would solve fuel problems. I dont want to EVER run into fuel problems.
If your system was boost referenced, it would not hold a steady pressure, it would rise with boost. Do you have a boost reference line running to your regulator? For example, if your base pressure is 60#'s, at 15#'s of boost, your fuel pressure should be 75#'s. Something is wrong with your fuel system. Something as simple as a vac/boost line not being attached to your regulator could be the problem.
If your system was boost referenced, it would not hold a steady pressure, it would rise with boost. Do you have a boost reference line running to your regulator? For example, if your base pressure is 60#'s, at 15#'s of boost, your fuel pressure should be 75#'s. Something is wrong with your fuel system. Something as simple as a vac/boost line not being attached to your regulator could be the problem.
62psi could be close or correctly funcitoning depending on what his base pressure is
for example if the base is 47 then 47+15 = 62; now if the base is 58 then its either not working right or there is a supply problem.
the pumps should be in parallel, if in series i would expect problems around your hp range.
for example if the base is 47 then 47+15 = 62; now if the base is 58 then its either not working right or there is a supply problem.
the pumps should be in parallel, if in series i would expect problems around your hp range.
Factory return lines and feed lines are fine...just tuned a Vette to 700rwhp with factory lines and 60's and had room to spare....if you want +800 rwhp go to a box and 86's or 96's. If 800 is enough keep the 60's and get your fuel pump system fixed....is the 420Bosch a 044pump? Does the factory pump feed it or is it an ECS style that is parallel? Your low fuel pressure under boost is the problem.