Fuel Pumps

[NoRice]

What pumping solutions is everyone using on their higher HP cars? My car has the Aeromotive Eliminator pump externally mounted under the rear fascia. After receiving the car and driving it one day here in Vegas in 108 degree heat for about 20 minutes around town, the car experienced a form of vapor lock. We assume it is do to the pump getting extremely hot and causing this. We switched the pump with a new one and the same thing happened within about 20 minutes. So I was wondering what pumps others are using and if anyone else has experienced something similar, or is this something only a car in Vegas, Phoenix or some other hot place would experience. We are thinking maybe a dual or triple intank setup is needed for areas like Vegas with the extreme heat in the summer.

 

[VIPER D]

Are you runing a return style system?

vd..

 

[NoRice]

Are you runing a return style system?

vd..

No.

 

[zorroespanol]

well, there you have it.

I posted a reply before but don't know where it went!

No return line will cause the pump to be stressed, when it is pumping into a line that is not flowing! (unless @ WOT).

besides the overheating, they will cavitatate and fill your fuel line with bubbles... (which will bring on the vapor lock that you have, as well as erratically firing injectors)

That dual or triple set up w/ no return will blow up your fuel line like Miles Davis cheeks blowing on a trumpet!!

Get a return line, and then check that you can maintain fuel pressure throughout the complete RPM range (under load, of course) then play it by ear.. need more pressure, add fuel pump.

Cheers!

 

[NoRice]

well, there you have it.

I posted a reply before but don't know where it went!

No return line will cause the pump to be stressed, when it is pumping into a line that is not flowing! (unless @ WOT).

besides the overheating, they will cavitatate and fill your fuel line with bubbles... (which will bring on the vapor lock that you have, as well as erratically firing injectors)

That dual or triple set up w/ no return will blow up your fuel line like Miles Davis cheeks blowing on a trumpet!!

Get a return line, and then check that you can maintain fuel pressure throughout the complete RPM range (under load, of course) then play it by ear.. need more pressure, add fuel pump.

Cheers!

The stock system is not a return style system is it?

 

[zorroespanol]

I don't know, I haven't worked on the SRT's engine to that extent..It would depend on whether the in-tank pump has a regulator.

I am in no way a Viper expert, I just know overall mechanics.

google "recirculating fuel sytem", you'll get in-depth explanation (and solutions) ... Also google "returnless demand system" (self explanatory)

 

[NoRice]

I assumed it doesn't as I see other when upgrading have installed a return line. I purchased my car in its present condition so I didn't know for sure. I come from vettes and we had to install a 97/98 return style system on my 01 when we upgraded the engine. I had a feeling that the lack of a return line in addition to not having a fuel controller was causing my problems.

 

[big-n-italian]

<< My car has the Aeromotive Eliminator pump externally mounted >>

part of the problem is here. i have read numerous times that these pumps overheat and "lock", and is a common problem with this brand external fuel pump. you need to go with either a weldon fuel pump if you want it to stay external, or upgrade the internal fuel pump which is what i did.

also, if you are running big HP, you will most probably need to upgrade your fuel system to a circulation system depending on your horsepower. yes, right now your fuel system dead ends at the motor.

i am sure you can find someone who has upgraded their internal fuel pump on a gen III to get assistance.

 

[ViperGMC]

The SRT has an in tank pump, that rearticulates (sort of) in the tank. I pulled out the internal pump and replaced it with two pumps in the tank. Ran a new line up to the fuel rails and used the old fuel line as a return to the tank. Works great and plenty of fuel for big HP and no heat issues.

 

[Tom F&L GoR]

You can also try this inexpensive, simple fix. Chrysler did this years ago on carbureted cars.

Run a small "T" from the outlet of the pump right back to the tank. Perhaps even to the to vent on the fuel filler neck where it will spill back into the tank. If you are particular, you can plumb in a small valve to adjust the flow. This will allow some fuel from the tank to enter the pump and prevent the fuel from overheating. It is not the pump getting too hot, only the fuel. (Odd to say so, but obvious.) You want this small bleed (perhaps think of it as a liquid vent) to not affect WOT fuel delivery to the engine.

Chrysler did this in the '80's, but with a fuel filter. The mechanical pump sucked out of the tank, pushed through the filter, which had a large outlet ****** for the carburetor and a small outlet ****** to run back to the tank. This prevented fuel from "sitting" in the fuel pump and getting overheated.

 

[Kai SRT10]

The SRT has an in tank pump, that rearticulates (sort of) in the tank. I pulled out the internal pump and replaced it with two pumps in the tank. Ran a new line up to the fuel rails and used the old fuel line as a return to the tank. Works great and plenty of fuel for big HP and no heat issues.

Are you using Walbros?

 

[NoRice]

The engine is a 522" with a paxton running approx. 8-9lbs. I am making roughly 780rwhp on pump 91 in 105 degree heat when they tuned it 2 weeks ago here in Vegas. I would prefer the internally mounted pumps as I think they would be quiet compared to the Aero. I have now, which is fairly loud. I am not sure if I can go that route now, as I am sure they did some mods to the tank and added some sort of sump probably when removing the stock internal pump. I will have to ask about the mods to the tank that were performed.

Can you elbaorate ViperGMC on your setup? I would like to run it by the builder. My local tuner and I were thinking of running 2 Walboros in the tank and eliminating the external Aero pump. I would think 2 Walboro 255s would be enough to supply my engine.

 

[ViperGMC]

Yes, 2 Walbro’s feeding the fuel rail through a Y into the back of each rail and then the front of the rail going to the fuel regulator and back to the tank. Make sense? There are a few pics in my gallery of the regulator and front hoses it that helps. It is quiet, well only a small wine when the fuel gets to 1/8 tanks or so. Access to the top of the tank is not too bad and the old fuel line makes a great return line. You can mount the pumps to the old assembly and pick up.

 

[Kai SRT10]

Yes, 2 Walbro’s feeding the fuel rail through a Y into the back of each rail and then the front of the rail going to the fuel regulator and back to the tank. Make sense? There are a few pics in my gallery of the regulator and front hoses it that helps. It is quiet, well only a small wine when the fuel gets to 1/8 tanks or so. Access to the top of the tank is not too bad and the old fuel line makes a great return line. You can mount the pumps to the old assembly and pick up.

What fuel rails are you using? Are they stock? Custom made?

 

[Viper X]

Hey No Rice,

My engine is similar enough to yours, 530", Paxton with currently 8 - 9lbs, 65 lbs injectors, all forged, etc. now at about 850 rwhp in very warm weather.

My current set up is twin Bosch 044's outside of the tank fed by twin "in tank" high volume (Walbro's I think) mounted at the rear corners of the tank. The in tanks feed the central in tank fuel cannister and the Boschs - mounted to a fuel log - pull from it through one -8 line.

One -8 goes up to one side of the fuel rail, with a -8 cross over. At the end of the other fuel rail is a -6 line which then connects to an Aeromotive fuel pressure regulator unit. The -6 returns to the tank from the regulator and empties into the central cannister.

We initially mounted the Bosch pumps in the tunnel and they overheated just like you describe. It took 1 hour in Vegas heat (on my way to the Silver State) and they vapor locked and stopped working. Their temp was about 185 degrees when they failed.

I have relocated the Bosch pumps to the area beneath the trunk, wrapped all of the fuel lines and both fuel pumps with ATP wrap, and shielded the pumps with Inconnel. On a 95 degree day with good humidity, they now run about 120 and are very quiet.

I have learned though trial and error that the first sign of an electric fuel pump struggling is when they get noisy.

I currently have no fuel overheating issues in 100 degree plus weather.

I have had West Coast Viper order a fuel cell to fit my SRT-10 so that I can mount the twin Bosch pumps in the tank (they did the fuel system) and that's what I'll do as soon as it is ready. I'd recommend you do the same, especially living in Vegas.

Heat will kill fuel pumps very quickly where you live, and that's no fun at all.

Good luck,

Dan

PS: Stock pump has a regulator attached to it and no return line.

 

[VIPER D]

well, there you have it.

I posted a reply before but don't know where it went!

No return line will cause the pump to be stressed, when it is pumping into a line that is not flowing! (unless @ WOT).

besides the overheating, they will cavitatate and fill your fuel line with bubbles... (which will bring on the vapor lock that you have, as well as erratically firing injectors)

That dual or triple set up w/ no return will blow up your fuel line like Miles Davis cheeks blowing on a trumpet!!

Get a return line, and then check that you can maintain fuel pressure throughout the complete RPM range (under load, of course) then play it by ear.. need more pressure, add fuel pump.

Cheers!

bingo!!!!!

vd..

 

[ViperGMC]

Not stock rails, not sure who makes them but I got them from RSI. I’ve seen them on another tuners car but can’t remember who. It has 3/8 NPT threads on both ends.