Hello, it's my first post on these forums.
I've been modding my 1999 WRX for E85. Goal was set to +300whp (I'm afraid my 5 speed would not want more
)
Mods so far, at least the ones I could remember right now
Td05-16g
EL headers
full 3" exhaust
1000cc injectors
Link G4+ plugin
ECU
AEM 320lph E85 fuel pump
Adjustable
FPR
Supertech forged pistons & Eagle Rods
I had a dyno session recently and we were only able to hit 300 crank HP due to fuel pressure dropping under load. We were monitoring the differential fuel pressure and it was dropping as load increased. The target was 350 kPA and when it dropped to 240 kPA we decided to call it off. It did not lean out since the
ECU uses differential fuel pressure compensation.
Since then I've been trying to locate the source of the problem. I have:
-Tried 3 different fuel pressure regulators
-Re-wired the fuel pump using thick wires (probably enough to support 40A) and a relay
-Verified that the fuel pressure sensor reads correctly. I also ran the
FPR with raised pressure and the vacuum signal disconnected. The drop in fuel pressure was observed (see fpdrop.png)
-Changed the inline fuel filter and even tried running without it
-Checked the fuel pump assy and the pre filter. Everything seems OK. The pump is almost brand new
So pretty much the stock fuel lines are the only thing I haven't tried to swap yet. I haven't just heard them becoming a restriction at these power levels. Has anyone here found out the limits of stock fuel lines?
Could the restrictiveness of the fuel lines found out by placing a pressure sensor right after the fuel pump and compare the reading to the one at the pressure regulator?
-Timo