Fuel Pump Rewire Science..

[xioca]

So I got put on the spot by a mechanic who honestly proves why I dont generaly like them. He asked why my car was down and I said I was rewiring the fuel pump. He goes on to how it doesn't need to be rewired and i'm breaking a perfectly good car and causing a major fire hazard if I get in an accident. Saying that I'm a total dumbass for listening to the entire dsm community for not proving I need it done. Apparently the voltage drop at the pump doesn't matter due to amperage and the pump will only has x amount of output.

So am I wrong in saying that with the voltage drop at the pump does affect it's output because it drops under, and how the do I word it cause it's annoying me.

 

[hewhoisknot]

The thin little wire does cause voltage drop. I never actually measured the voltage but the before and after effects are definitely felt, for me most noticably at idle.

BUN

 

[Black Venom]

This mechanic is a moron Voltage matters just as much as amperage. Ie: Your computer actually varies the dead time of the injectors dependent upon voltage. (not amperage)

I bet he bashes you for driving an import.

 

[andymoraitis]

Print out this page:

http://www.roadraceengineering.com/fuelpumpflowrates.htm

And then kindly tell him to go shit in his hat.

Have fun,

Andy

 

[Soup Can]

tell your mechanic to go back to the electrical part of his ASE course...voltage drop increases as wire "girth" remains constant and distance increases...Theres a nifty chart all over the internet of wire sizes and max distances till voltage drop...infact when I took the course they gave us a copy of the damn chart...the rewire is one of the first mods I did on all of my dsms..not to mention on the fire hazard note have him measure the temp the to stock wire vs. the temp of the thicker wire...should notice atleast a 3 degree temp drop in the thicker wire...if anything the thinner wire would catch fire first from overheating...the only part i argue about with the rewire is puttign the thick wire after the relay for all 2inches of travel...that in my opinion does nothing over stock...

 

[eric91gst]

Print out this page:

http://www.roadraceengineering.com/fuelpumpflowrates.htm

And then kindly tell him to go shit in his hat.

Have fun,

Andy

-

 

[Splitpi]

v=ri

voltage = resitance * current

http://www.powerstream.com/Wire_Size.htm

The rewire uses 10 guage versus the factory stock of I believe 16 guage (some one correct me if I'm wrong).

10 Guage causes a voltage drop of about 0.279 volts versus the 16 guage which drops about 1.133 volts (assuming 8 ft of wire and a 17 amp load). All wires have reistance its just usually that does not significantly affect the end product. Much like why power companies transmit power at insane voltages (hundreds of thousands of volts) with low current (v=(resistance in the line) * (current)) versus high current and low voltage as the line resistance plays a larger factor in syphoning power.

I hope that makes sense... and I don't want to break out my electrical engineering books to explain it more detail... its been a few years since college.

 

[Merkles]

v=ri

voltage = resitance * current

http://www.powerstream.com/Wire_Size.htm

The rewire uses 10 guage versus the factory stock of I believe 16 guage (some one correct me if I'm wrong).

10 Guage causes a voltage drop of about 0.279 volts versus the 16 guage which drops about 1.133 volts (assuming 8 ft of wire and a 17 amp load). All wires have reistance its just usually that does not significantly affect the end product. Much like why power companies transmit power at insane voltages (hundreds of thousands of volts) with low current (v=(resistance in the line) * (current)) versus high current and low voltage as the line resistance plays a larger factor in syphoning power.

I hope that makes sense... and I don't want to break out my electrical engineering books to explain it more detail... its been a few years since college.

thats funny, Im at college now and my Electrical Science Final is coming up in 2 weeks . Sorry for being off topic I just thought it was funny that someone busted some e-sci out on the forum.