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Evo How Tos / InstallationsPost or link to your detailed how to / installation articles in here. If you have any questions regarding the how tos, feel free to post them in the Request sub-forum.
I suggest wiring it up parallel with the factory Relay #3. Do a search on rewiring fuel pump while keeping factory dual voltage system.
Sorry for rhe confusion.
Last edited by 2006EvoIXer; Mar 12, 2018 at 12:52 PM.
And it appears that on usdm models that the wire that you want is white like the picture I provided based on the fact that it is white at the pump. (It is not confirmed but I am making and educated guess.....)
anyone see any drawbacks? I feel that it is a little cleaner install. I would rather cut the wire there than at the top of the sending unit personally
You lose the low flow voltage (8V) by doing this. Your fuel pump will run at 100% (14V) when off boost. Side effect is your fuel pressure at idle jumps from 33psi to 45 or 55 psi because the return line is too small. Also, you will need to add to ground wire. Doesn't help to increase power wire and not increase ground.
By connecting there, you will lose a little voltage from the 14V at the battery. I haven't fully tested my setup yet, but I think the biggest voltage drop is going through fuel pump relays 1 & 2. Hopefully, I'll have time to check this weekend to get a better picture of where the inefficiencies are.
Last edited by 2006EvoIXer; Mar 15, 2018 at 07:12 PM.
I am countering the loss of the 8v low voltage with a aftermarket fpr and drilled out siphon
I guess what I was asking is. Will I be splitting hairs between voltage drop with hooking up here vs 2 ft down the line at the plug on the sending unit?
i was comparing this way that I referenced with the original "how to"
I am countering the loss of the 8v low voltage with a aftermarket fpr and drilled out siphon
I guess what I was asking is. Will I be splitting hairs between voltage drop with hooking up here vs 2 ft down the line at the plug on the sending unit?
i was comparing this way that I referenced with the original "how to"
it will drop voltage slightly. What are your mods? If you will be close to running out of fuel, it could make a difference.
I just looked. It won't make enough difference if you want a clean install. 0.05V is nothing.
Last edited by 2006EvoIXer; Mar 15, 2018 at 07:24 PM.
andbif I definitely should.... should I tap into this wire here? Wire the relay to the "car side"? Then just ground that wire to the chassis? It wouldn't make a difference to Hook it to 10awg and hen hook to chassis would it?
andbif I definitely should.... should I tap into this wire here? Wire the relay to the "car side"? Then just ground that wire to the chassis? It wouldn't make a difference to Hook it to 10awg and hen hook to chassis would it?
You should do ground too. Otherwise, it isn't a complete rewire. I read somewhere that just grounding with 8 or 4 awg bumped voltage up 0.5V. You can tap that wire to keep it clean, but make sure to verify that is the correct wire before tapping it.
You should do ground too. Otherwise, it isn't a complete rewire. I read somewhere that just grounding with 8 or 4 awg bumped voltage up 0.5V. You can tap that wire to keep it clean, but make sure to verify that is the correct wire before tapping it.
so would I have to retune if I were to ground that wire?
i might just add the ground and keep the factory stage 2 pump power. But if I need to retune then I might just forget the whole thing.
Strictly my opinion: I think the retune is needed at the high end where your injectors are at its highest duty cycles. Although the pump will flow more once the relay switches to 14V, your low duty cycles won't be much richer than tune. For my car, I was hitting 104 IDC at about 6000-7000 RPM. With my overkill rewire, that's when my AFR dropped another 0.5 (from 10.7 to 10.2). You need to look at your tune and see what AFR it was tuned for.
