tkelly27
15+ Year Contributor
- 1,712
- 27
- Mar 11, 2007
-
Gresham,
Oregon
I've got a neat little B&M AFPR cap, but it overruns now that I have a 255 pump. Many cars drop the fuel pump voltage at lower RPM (you can find it in Mitsubishi, GM, Acura, and Nissan, among others) so I thought I'd give it a shot.
RRE has a good write up about the EVO system
RRE's EVO Fuel Pump Info
I found that the EVO 6 uses a .55ohm, and EVO 7 and up use a .75ohm. These are big resistors to handle a fair bit of power. If you've ever seen one, they have heat sinks. I'll be able to have a better idea of how much power I need when I figure out the drop across it.
Not having a potentiometer that can handle big wattage, I used some spare spools of speaker wire. With the stock wiring the whiney sob is tamed somewhere between .8ohms and 1.8ohms. I will wait until I run a big wire to try and figure out what the final value should be.
I'm torn between triggering the 2nd relay with an ECU output (reliable, adjustable, repeatable) or a hobbs switch set at whatever vacuum level seems to fit best (leaves reliable, adjustable, repeatable output from ECU free).
All in all, I think it will be somewhere around $20, plus the cost of the re-wire kit. If you already have relays and wires, the final resistor should be in the $5 range. Seems cheap and easy to me compared to an Aeromotive. Plus, no braided stainless. I can't stand braided stainless.
I'll run the big wire tomorrow. You'll know more when I know more.
RRE has a good write up about the EVO system
RRE's EVO Fuel Pump Info
I found that the EVO 6 uses a .55ohm, and EVO 7 and up use a .75ohm. These are big resistors to handle a fair bit of power. If you've ever seen one, they have heat sinks. I'll be able to have a better idea of how much power I need when I figure out the drop across it.
Not having a potentiometer that can handle big wattage, I used some spare spools of speaker wire. With the stock wiring the whiney sob is tamed somewhere between .8ohms and 1.8ohms. I will wait until I run a big wire to try and figure out what the final value should be.
I'm torn between triggering the 2nd relay with an ECU output (reliable, adjustable, repeatable) or a hobbs switch set at whatever vacuum level seems to fit best (leaves reliable, adjustable, repeatable output from ECU free).
All in all, I think it will be somewhere around $20, plus the cost of the re-wire kit. If you already have relays and wires, the final resistor should be in the $5 range. Seems cheap and easy to me compared to an Aeromotive. Plus, no braided stainless. I can't stand braided stainless.
I'll run the big wire tomorrow. You'll know more when I know more.