MIGHTYMOUSE

iTrader: (59)

if you are going to street drive on a race pump or multiple running pumps you should not have:

-small return line / regulator
-low fuel level
-small gas tank
-far to go

higher fuel temperatures often combine with distances /uphill /restriction between fuel and pump resulting in vapor lock/cavitation/complete loss of fuel pressure (bad).

some people 'don't have problems' but there are risks. people also survive lightning strikes.

my advice is to avoid what you can and compromise with what you can't

for me there was less risk using multiple oem quality pumps a oem quality relays; and testing the system to verify function before using it.

I never once had a failure with those components in all of my driving or true street racing, tho every season I would rotate the 'full time' pump with one of the others.

PUNISHER TA

iTrader: (13)

I run stealth pumps.

I used to have my second pump triggered by a hobbs at 2psi. Fuel pressure was dropping on part throttle pulls and even WOT pulls and was making it stumble, so I wired them both full time. Car idles at 15.5 AFR 58psi. with a -6AN return, no issues. E85.

I am going to add a third pump and that will be hobbs.

allout06

iTrader: (11)

im running a -6 return also with a magnafuel FPR. twin walbro 450's. itll be on E85 when its ready to go to the dyno.

soundengineer

iTrader: (16)

you've missed quite a bit there...
most of the wear and tear of any item comes upon initial power up....this is a well known fact amongst any manufacturer.
the best example is a light bulb....leave it on and dont touch it, it will last for years and years...
turn it on and off, you shorten its lifespan(think towards the bulbs burning in the smithsonian....that have been on for 75 years on display......)
this same thing happens in motors(electric like the pumps)
turning it on is what puts wear and tear into it...
and I'm not saying your pumps are going to wear out immediately...but I guarantee the one that turns on and off will wear out before the one that runs constantly on your setup.

theres always a slight surge when you turn on another pump...
you dont think the regulator is some magical device that will suddenly instantly auto correct...it takes it a second to stabilize..
that second pump will create a sudden change in pressure for a short time.

giving me an example of mightmouse show me you dont understand hardcore racing...
those guys rebuild/replace pumps on a regular basis, they dont let it have the chance to fail....hardcore racers dont wait for things to break.

you trying to use the 20 gallons example doesnt work either...

the flow is not increasing if the pressure didnt change
laws of physics...pressure goes up, flow goes down
flow goes up, pressure goes down
the pipe can only flow so many gallons of fuel per hour...period...

having 1 pump on or having 7 pumps on doesnt change how much fuel goes thru your lines, only a change in pressure will change how much fuel gets thru your lines
the only thing more pumps do is make it so that you will have enough flow to keep fuel pressure constant as your injectors try to drain your lines

MIGHTYMOUSE

iTrader: (59)

dang dude.

-any brushed / vane pump that runs will be wearing out while it is running, the less it runs, the longer those components will last, your comparison has no moving parts, and if fuel pump motor windings begin to glow you got bigger problems.
-of course there is a bump in pressure when more pumps come on line no biggie
-he is talking about me. see above where i have never replaced or had a failure, over the course of 10 years using that type of system.
-the flow certainly increases, even if the pumps were in series there would be a slight increase in flow. three pumps in parallel below. notice the flow change

soundengineer

iTrader: (16)

all you have in that video is something showing a pressure increase and a first pump that doesnt flow enough to build pressure in that fuel line

its simple physics..
once you flow enough to start building some pressure, your pressure/flow relationship will stay the same.....it is an inverse proportion...
doesnt matter if you have 1 pump or 7 pumps...
the fuel might shoot out harder, but its the same amount of fuel either way.

Boosted Firehawk

iTrader: (11)

So steeet driven or not 2 pumps all the time can be done with minimal to zero issues is the consensus? ?

soundengineer

iTrader: (16)

correct.. no problems....many people driving with both pumps on all the time

Torqueshaft

Lets address #1 first...

You are right about the light bulb but only because it has a filament.
The reason you are right is because of the thermal shock of extreme temp changes of the filament when the bulb is shut on and off vs the stable filament temp when it is left on.

A electric motor is a very different animal and a pump even more so...

You have things like bushings/bearings, brushes (if it has them) pump seals, impeller etc. which all wear a lot more in continues use vs intermittent use.

#2 You again are right about flow vs pressure...

But you miss the mark on your 1 pump vs 7 pump scenario...

Because it is a "closed" system we are dealing with and as you have pointed out we have only so much flow/pressure until the PR sees a reduction in pressure and allows more flow, having 7 pumps deadheading vs 1 pump will increase the temp of the fluid.

mr_biscuitz

iTrader: (22)

No issues here either

soundengineer

iTrader: (16)

sure...temperature is gonna increase...by a very small smount...
again... you missed the point where I measured temp increase and over 20 minutes it was 2*

the pump itself doesnt add enough heat to worry about.

stevieturbo

2 x 044's for several years with no issues.

IMO Keep it simple.

That said, Aeromotive do now make a sensible controller if you wanted to vary pump speed with demand ( well rpm is what they offer which for most is quite fine )
It's rated for 40A, so should be able to handle 3 x 044's or certainly a pair of the "big" Walbros.
The current the bigger Walbros draw is ridiculous though

http://aeromotiveinc.com/products-pa...ed-controller/

atomic 6

I wouldn't say it is the consensus, maybe the consensus of those that posted here.

But I would agree with MightyMouse, over the "consensus" here.

MightyMouse is a reliable source of good "real world" experience/information.

In my own experience...

We have been running multi-pump setups, with Hobbs switches, in the TurboRegal world since the beginning of time, with very little problems.

This year on DragWeek there were a lot of "vapor lock" and over heated fuel issues, mainly because of people trying to run a larger fuel pump on the street, a twin pump setup(like we run) usually doesn't have any of those issues.

Some fuel tanks were so hot you could not touch them.

Our old turbo Fairmont had jumo one external 255 pump, and 22 volt voltage booster(msd boost a pump) and it would make the fuel hot to the touch after five or six 1/4 mile runs.

If you run a mutli-pump system, don't leave the second pump on all the time....

Forcefed86

iTrader: (4)

For what it's worth my magnafuel 750 protuner pump with 1/2 supply and OEM 3/8th steel hardline return would heat the crap out of my fuel. Anytime I let the fuel get down to 6-7 gallons I was seeing 150*+ fuel temps on a hot summer day. Got to the point it would shut the car off. I swapped in 2 inline walbros (wired to both come on at the same time) and it no longer had an issue. E85 OEM fuel tank

On my new car I run the same Magnafuel 750 pump with a 1/2" return and I don't have that issue. (FPR was changed as well).

stevieturbo

Build the setup right, and there are no downsides or problems with running multiple pumps all the time.

Build it poorly, and you could run into problems with 1 pump or 2, 3, 4 etc.

If you think heat is going to be a concern, add a fuel cooler and/or run a larger. But most heat comes from circulating fuel through hot rails/engine compartment. Only a small amount of heat comes from the pumps themselves.

oscs

iTrader: (19)

My setup is as follows: Each -8 line from the sump goes to a 255 pump those two -8 lines lead to a T where it exits as a -10 that main line carries the fuel to just before the rails where anther -10 to -8 -8 devides the fuel to each rail. The return line is a -8. Both pumps run all the time in houston heat and I've never had a problem. I've been using this system with just over 400hp so I'm sure it's returning way more than it's using.

atomic 6

So you are saying.

A fuel pump that generates heat, and is cooled by the fuel(conduction transfer), will add LESS heat to the fuel, than a convection transfer of heat to the rails and lines, from under the hood temps?????

That actually makes very little scientific sense.

And in my experience is not the case.

stevieturbo

How cold do you think the engine/engine compartment is ? And as the rails are often bolted to, or damn close, there is conduction as well as convection.
And most engines will be running at 160degF or warmer...that's a LOT of heat

The pump itself will never generate anywhere near the same amount of heat an engine does ! Or a hot engine compartment.
Even a dozen pumps probably wouldnt do it.

Torqueshaft

When you live in AZ. like I do and your fuel is all ready at 115+ any little bit helps...lol

And if you were running 7 pumps like your example and based on your two pump test...They would add 14 degrees to the fuel temp which would continue to increase the longer the pumps were running.

allout06

iTrader: (11)

how about we hear from the people that have had failures do to wiring them together..

*crickets*