Thread: The alt rewire mod actually DOES increase fuel mileage!!

Originally Posted by SyntheticShield

Well you got two paths now to the fuse block from the alternator. True, it will for the most part, take the path of least resistance, so the vast majority will be carried by the alt. re-wire run, but you still have some going across that original wire thats considerably smaller and pushing about 8' in length.

From just purely an electrical standpoint, Id want all the power going across the one wire. Unless you're keeping the stock wire in there for back up, and at that point if that is the case, why not install two alt. rewires?

I get you now Scotty! My big question, kind of inline with Lee's would be, how do I go about fishing this 8' wire out of my engine? If it is a problem, all be it a small one, could I just not remove the smaller wire thus eliminating the 2 wire theory then? Or is the factory alt wire hooked to other things before it reaches the fuse box?

Originally Posted by GeddyLee

I get you now Scotty! My big question, kind of inline with Lee's would be, how do I go about fishing this 8' wire out of my engine? If it is a problem, all be it a small one, could I just not remove the smaller wire thus eliminating the 2 wire theory then? Or is the factory alt wire hooked to other things before it reaches the fuse box?

You dont. It runs from the alternator, towards the drivers side, through that harness that runs over the blower, then it goes to the front of the engine bay then back to the passenger side then back up to the fuse box. It is running about 8 - 10' to make essentially a 2' run. But that wire is taped in the harness, so you wont be fishing it out without opening up the harness and taking out the tape that is loosely wrapped around it.

What I did with mine is just disconnected it on both ends, taped up the connector so it would not short out against anything then secured it so it would not be flopping around. But I have always planned that once I had to do any major work, such as I am now, that I would take the time to pull that wire out of the harness.

That wire is not hooked to anything else, it goes straight (albeit the long way) from the alternator to the fuse box. I used an multi-meter to check that when I pulled mine. I suppose if one wanted to fish it out of the harness it could be done, but its going to be no easy or quickly done task.

Now, that all said, I want to restate, there is nothing wrong with leaving it hooked up, but as I mentioned it seems pointless to me to do so. Although the current that would run through the OEM wires vs. the new alt. rewire is small in comparison, it is still some measurable amount.

Think of it like this. You take your garden hose and want to hook up to a Y connection. One side of the Y is a 3" pipe, the other side is a 1/4" pipe. While the vast majority of the water is going to take the path of least resistance through the 3" pipe, there is still some diverted to through the 1/4" pipe. In this case, the 1/4" pipe is the OEM alternator wire. What gets diverted around that wire is significantly reduced by the time it gets to the fuse box because of the resistance of the wire.

If you do the math on the resistance of that wire from the alternator with the current you can push with the alternator, you'll see that you can drop about 1 - 1.5 volts across that wire. So why leave it in there with the alternator re-wire. If you are going through the trouble, however little it may be, to install the alternator re-wire, then disconnect the OEM wire and get the full benefits of the re-wire, not 98%.

Anyway, just my thoughts on it. Ive done the math on it and if Im going to modify something then I want maximum results from the work.

Has anyone measured the volts?
1. OEM Wire only
2. OEM and Rewire connected
3. Rewire only

That would probably put the best perspective on things...

I haven't done the rewire yet, but I hope to order the rewire and voltage booster by the end of the month.