TBI Swap Fuel Pump Quandary

[JCampbell]

I'm getting ready to order my fuel pump for my TBI swap. I'm planning on running the Carter P5001, but after looking at the specs of the P5001 vs. the P5000, I have a slight hesitation.

The P5001 runs 9-22 psi @ 50 gph whereas the P5000 runs 22-75 psi @ 50 gph.

The numbers fluctuate depending on who you ask, but seeing as how TBI only needs anywhere from 9-13 psi, is there any advantage to running the larger pump? It's never going to be a high-horse, monster engine. Just a real streetable 454 with a small RV/towing cam and intake.

[76stepsidechevy]

I went through the same thing, Im running a holley projection tbi setup and I got it used without the pump. I read a bunch of threads trying to find out what pump to use and in the end I just ordered one from howell. What showed up was an airtex E2000 pump with a rubber sleeve on it for twice the price. It seems to work fine though, actually im still in the tuning stages and most of the time my a/f gauge reads rich so theres no lack of fuel. I'd rather have more pressure and be able to regulate it down then not have enough and need to buy the bigger pump later.

[TheApocalyptican]

Originally Posted by 76stepsidechevy

I'd rather have more pressure and be able to regulate it down then not have enough and need to buy the bigger pump later.

This is the biggest reason for a "higher pressure than it needs to be" fuel pump.
I'm running an ACDelco EP381 in tank pump. It's supposed to be good to like 51psi. The fpr keeps the pressure at 13, and any "leftover" fuel takes a ride on the return line back to the tank.

[JCampbell]

So go with the P5000?

[gchemist]

Are stock fuel pumps not an option?

[Pyrotechnic]

The problem with running an external electric pump with the carburetor pickup is the lack of any kind of baffling. When the tank gets under half full, the fuel will slosh back and forth as you accelerated and brake. This will uncover the pickup and allow it to suck air. Add a return line, and the problem is magnified because the pump is flowing a lot more fuel all the time. A carburetor can bleed off the air, but there are probably much worse consequences with fuel injection. Regardless, it's not good for electric pumps to suck air. I ran an electric pump this way and it worked for awhile but it is now dead. You can hear the tone of the pump change every time it sucks in air.

In contrast, a mechanical carburetor fuel pump doesn't care what it pumps because of how it's designed and a carburetor can easily bleed off any air in the line. This is why there is no baffling in the stock setup because it is just not a problem.

The TBI systems in these trucks came with a tank that had internal baffling and an internal electric pump. This is probably the BEST way since it's how GM engineered the system to work. If you want a higher pressure pump, there are factory pumps that will fit in place of the TBI in tank pump. Your best bet is to get a TBI tank, sending unit, and fuel pump.

[JCampbell]

I've got baffled tanks, thanks.

[cforshey71]

With the external pump mounting location... A lot of the pumps state it needs to be mounted parallel or below the pickup point. The only option there is half way down the frame rail. I'm running a Holley 4060 FI electric pump. Does anyone know if mounting it on the crossmember in front of the tank is too high???

[JCampbell]

I mounted mine down low on the inside of the pass. frame rail just ahead of the tank. It's definitely below the bottom of the tank and pickup point.

[cforshey71]

I should mention I have a 71 chevy shortbed with the tank moved under the bed. i am running a chevy 350 tbi set up which has is internally regulated at 12-15psi. The return line is tapped in as an air bleeder for the pump as well. I'm just concernced the pump will not be able to "pull" and then "push" effectively being mounted higher than the pick up point, but I cant keep it close to the tank otherwise. Any tips or wisdom would be greatly appreciated!!