So I've recently gotten tuned by Dent Sport. I've got my FSP EJ22 project putting about 120-130 awhp out. It was 122 on the dyno, but we were unable to adjust ignition timing at all due to my own wiring issues. Now that I've adjusted them, I have added another 10lb-ft of torque or so in timing (measured with G-Tech), so that's about where I am for power right now. More details, if you're interested, at http://www.jenandneil.com/28fsp.
Anyway, we noticed on the dyno that torque really really drops off after 5200RPM or so. By "really really" I mean that it goes from about 120lb-ft of torque to somewhere in the 80s. It's pretty sad. The fuel injectors are running overtime with about a 92% utilization rate and mixtures are really rich no matter how lean we tried to make it. We suspect the injectors aren't actually closing, so fuel is basically just spraying non-stop into the cylinders after 5500 or so.
So I'm trying to rectify this. I've got the stock fuel pump (??lph), stock injectors (280cc), and stock fuel pressure regulator and I want more fuel. I'm curious how others have approached this problem. I haven't yet hooked up a fuel pressure gauge anywhere to see how the fuel pump is keeping up and I can't find anywhere even an estimate of the flow capacity of the stock pump.
1. I could get a new fuel pump and assume that fuel pressure is dwindling at the top end. I don't suspect this is the case, but I'd love to hear someone else's experienced opinion here.
2. I could do a fuel pressure regulator, increase fuel pressures, and consequently lower the injector durations to get the fuel into the cylinders faster and allow more space between injector pulses.
3. I could replace the injectors. 440cc WRX would certainly flow more than the 280cc ones I've got and I could decrease the injection duration to accomodate that. It's not such a big jump that I expect to have any idle troubles with that and it's not a daily driver, so even some idle issues are just fine by me.
Anyone have any valuable experience I could learn from?
Can I assume that any top-feed Subaru injectors will fit or are there fitment issues with certain injectors?
Should I just assume that all options will require a new bigger fuel pump?
Does anyone have any good experience with electronic fuel pressure gauges that I can run inside the car or is that not worth the effort/money?
Thanks in advance!
-N
Anyway, we noticed on the dyno that torque really really drops off after 5200RPM or so. By "really really" I mean that it goes from about 120lb-ft of torque to somewhere in the 80s. It's pretty sad. The fuel injectors are running overtime with about a 92% utilization rate and mixtures are really rich no matter how lean we tried to make it. We suspect the injectors aren't actually closing, so fuel is basically just spraying non-stop into the cylinders after 5500 or so.
So I'm trying to rectify this. I've got the stock fuel pump (??lph), stock injectors (280cc), and stock fuel pressure regulator and I want more fuel. I'm curious how others have approached this problem. I haven't yet hooked up a fuel pressure gauge anywhere to see how the fuel pump is keeping up and I can't find anywhere even an estimate of the flow capacity of the stock pump.
1. I could get a new fuel pump and assume that fuel pressure is dwindling at the top end. I don't suspect this is the case, but I'd love to hear someone else's experienced opinion here.
2. I could do a fuel pressure regulator, increase fuel pressures, and consequently lower the injector durations to get the fuel into the cylinders faster and allow more space between injector pulses.
3. I could replace the injectors. 440cc WRX would certainly flow more than the 280cc ones I've got and I could decrease the injection duration to accomodate that. It's not such a big jump that I expect to have any idle troubles with that and it's not a daily driver, so even some idle issues are just fine by me.
Anyone have any valuable experience I could learn from?
Can I assume that any top-feed Subaru injectors will fit or are there fitment issues with certain injectors?
Should I just assume that all options will require a new bigger fuel pump?
Does anyone have any good experience with electronic fuel pressure gauges that I can run inside the car or is that not worth the effort/money?
Thanks in advance!
-N