fuel pump and rewiring...

[96spyderman]

I was just wondering what the benefits of rewiring your fuel pump are aside from no fuel cut...
Is it even worth it for a lower end modded engine? I'm only running 12-13 PSI currently and if I ever get my MBC in i'll only boost to about 15

[JoeWagon]

Rewiring the pump doesn't prevent fuel cut. Fuel cut is something that the ECU does based on airflow/revolution. The benefit might not be there on a stock setup unless you plan on pushing it, but whenever you get an upgraded fuel system, make sure you do rewire.

[kjewer1]

Here is how I look at it. Rewiring the pump gives a very substantial boost in fuel flow, making the pump bigger in essence. Look at any flow chart (or RREs page) that shows flow vs pressure for both 12v and 13.5-14v if you dont believe me. THEN, consider that it costs like 15 bucks to do it

Another thing I find funny is that poeple with big ass pump think they dont need to rewire. The supra pump pulls up to 21+ amps. I dont know about you, but I dont want 21 amps running through a 18 guage stock wire.

People will also say that "If I dont rewire my big ass pump, I wont need a big ass regulator." Doesnt really work like that. For one, flow at low pressure varies slightly between the two voltages, and between the 255 HP and LP. For two, you still have a big ass pump. Get the reg.

[metalhedskater]

Originally Posted by 95 GSXracer

Another thing I find funny is that poeple with big ass pump think they dont need to rewire. The supra pump pulls up to 21+ amps. I dont know about you, but I dont want 21 amps running through a 18 guage stock wire.

People will also say that "If I dont rewire my big ass pump, I wont need a big ass regulator." Doesnt really work like that. For one, flow at low pressure varies slightly between the two voltages, and between the 255 HP and LP. For two, you still have a big ass pump. Get the reg.

Umm could you DUMB this down for the people who are still trying to learn as they go along and for the dumb people?....because i would like to boost my stock turbo at like 18 to 19 because i rarely ever go over 5 psi as of now....i drive my car pretty normally...i would just like that extra boost when i need it ....aslo i really dont care about killing the turbo because im soon going to buy another one anyway...

[JoeWagon]

Rewiring the stock fuel pump will not help your setup. It would only help if you were going to get a 14b and push the car as fast as it would go without upgrading anything (fast for little money).

Kevin says some people think that since they have a big enough pump, they won't need to rewire for the extra 'boost' it gives on flow. It's wrong because the stock wiring isn't that great for a big power drawing pump. Another misconception is that if they don't rewire it, they won't need a fuel pressure regulator (which you need if you have a large pump). That's wrong because the PRESSURE regulator regulates pressure, and rewiring doesn't affect pressure, just flow. Also, it's just silly to think you can avoid buying a FPR because it's not rewired. If you have a big ass pump, you NEED a FPR.

[kjewer1]

Yup that about sums it up Wagon. I'll give one example. The common internet belief that a 255HP will require a aftermarket regulator but the regular 255 wont, because it flows less.

At 73 psi (30 psi boost asuming 43 base pressure. Base plus boost (1:1 ratio) equals fuel presure) the LP flows 183 lph. The 255 HP flows 221, substntial increase! But at 43 psi (0 psi manifold pressure), They fow 261 and 264. You're not going to see much difference in fuel delivery between those two pressures. At idle you will be below 0 psi manifold pressure (base pressure minus vacuum equals fuel pressure, 1:1) so the difference is even smaller.

The difference is bigger between rewired vs stock wired. But the benefits at high boost far outweigh the extra flow at idle. And with a high current pump I would take any chances.