Walbro 450 lph e85 fuel pump diy evo 8/9
#183
#187
Evolved Member
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I have just installed one of the E85 pumps on a car. Had serious fuel pressure drop off under load. Spent/wasted some time diagnosing issues. What I have found is that these pumps seem to be very sensitive to voltage, more than the 255 pumps. On stock wiring they perform the same or worse than a 255. Once you upgrade the wiring then you see the difference. Maybe a lot of these people with lean issues are running the stock wiring.
#188
EvoM Guru
iTrader: (6)
When set to factory (43.5 psi) base pressure:
The Walbro 255 lph pump @ 30 psi boost draws about 10.5 A @ 13V.
The Walbro 450 lph pump @ 30 psi boost draws about 17.5 A @ 13V
The Walbro 450 draws 67% more current than the 255 under these conditions, and it is a well-known fact that the factory wiring cannot support a 255. Simply put, the terms "Walbro 450 pump" and "factory wiring" do not belong in the same sentence.
#191
When set to factory (43.5 psi) base pressure:
The Walbro 255 lph pump @ 30 psi boost draws about 10.5 A @ 13V.
The Walbro 450 lph pump @ 30 psi boost draws about 17.5 A @ 13V
The Walbro 450 draws 67% more current than the 255 under these conditions, and it is a well-known fact that the factory wiring cannot support a 255. Simply put, the terms "Walbro 450 pump" and "factory wiring" do not belong in the same sentence.
The Walbro 255 lph pump @ 30 psi boost draws about 10.5 A @ 13V.
The Walbro 450 lph pump @ 30 psi boost draws about 17.5 A @ 13V
The Walbro 450 draws 67% more current than the 255 under these conditions, and it is a well-known fact that the factory wiring cannot support a 255. Simply put, the terms "Walbro 450 pump" and "factory wiring" do not belong in the same sentence.
#192
EvoM Guru
iTrader: (6)
12ga may be sufficient if the length is no more than a few feet, but not for long runs. Crutchfield's wire guage chart supports this. I wouldn't recommend anything less than 8ga, especially if the battery is still under the hood. My setup uses 4ga power and ground straight to the battery (in the trunk), and that's enough to keep 14.3V on twin 255s at full tilt. One really needs 20A capacity with some headroom to be sure.
Last edited by Ted B; Jan 19, 2015 at 04:33 AM.
#193
EvoM Guru
iTrader: (50)
12ga may be sufficient if the length is no more than a few feet, but not for long runs. Crutchfield's wire guage chart supports this. I wouldn't recommend anything less than 8ga, especially if the battery is still under the hood. My setup uses 4ga power and ground straight to the battery (in the trunk), and that's enough to keep 14.3V on twin 255s at full tilt. One really needs 20A capacity with some headroom to be sure.
http://www.crutchfield.com/Learn/lea...uge_chart.html
However, perhaps more interesting is the voltage drop estimate on this website:
http://www.bulkwire.com/wireresistance.asp
For this webpage, a 13 ft run of 10 gauge running 20 amps at 13.8 VDC will have a 0.26 V drop. 8 gauge is 0.17 V, 6 gauge is 0.1 V, and 4 gauge is 0.07 V. I'm actually at 10 gauge with my install, but must admit that I find 8 gauge a bit more preferable. 4 gauge is definitely the ultimate.
#195
My battery is in the trunk and my wiring is very short. Maybe 2.5- 3 foot total with an inline fuse and a 30a relay. I have 2150's, single walbro 450 intank, fuel labs regulator, stock lines. Are you guys wiring 4-8g wire in the top of the hat?