DCOE - Mechanical Fuel Pump

[240zip]

In reading up on DCOEs there doesn't seem to be a solid consensus on whether one should keep the mechanical fuel pump in conjunction with the low-pressure high-volume electric fuel pump. People with triple DCOEs on Jags tend to keep them. Any opinions (one way or the other)? The only agreement was 3 PSI for the pressure and ensuring one had sufficient fuel flow.

[xonix_digital]

I plan on keeping both since I have had no issues. If you can think of a reason to remove one of them then go for it. I think it depends a lot on your motors fuel appetite and the benefit you think you would see by removing one of them.

[LowCarbZ]

I plan on adding a Holley electric pump and a regultor. I want to clean up the engine bay and really don't see the use of having the mechanical pump.

[crazyoctopus]

ran just on the mechanical and never had an issue.

 

I say run just the mech pump, and if you have issues then get an elec.

[Lazeum]

 I used to have a stock N42 head, Flat tops with Schneider Stage II cam and 40DCOE. With this setup, I never had any problem. Car was running strong with no fuel starvation.

 

Now, I'm running a Port & Polish head with Rebello cam, mech fuel pump is not able to keep up; I had fuel starvation in full pull at WOT in 4th & 5th gears on highways. AFR are however quite rich (10.5AFR at WOT), it could also explain why I needed so much fuel. I had to let off, wait for 5 seconds prior to get some power again.

 

So I've moved to a elec fuel pump and it has fixed the problem.

 

Bottom line is if you have a nearly stock setup, you should be fine. If you have done extensive mods, mech fuel pump might be not enough.

 

My advice would be to run your car and see how it goes; problem will only appear at high speed, your car will still be driveable even it mech pump is not good enough. It would then be time to think about upgrading your system with the confidence you need it 

Edited September 23, 2010 by Lazeum

[240zip]

Thanks for the feedback. I'm surprised that people have been able to run DCOE's with a mechanical fuel pump. I think we'll keep the mechanical pump, our fuel regulator, and add the electric pump near the fuel tank. I have a pump block plate, so I may remove it at some point in future.

[LowCarbZ]

^ I've got an early 74 260Z so it has the factory electric pump as a secondary (which actually just started working again recently.) I don't see a benefit either way to having it or not having it. Once the fuel line is pressurized that's a constant. So an electric pump set to the right PSI should be more than adequate IMO but there may be other parameters here that i'm not considering?