But a W340 in series with a B044 will get you closer, 80 gph at 80 psi

Here are some fueling calculations I have done on some pumps to give them a decent comparison. I use an 80% usage and BSFC of .60 which is more of a boosted setup, but these'll give you decent numbers.

- Walbro 255lph in tank pump
220lph @ 58psi @ 12 volts / 260lph @ 58psi @ 14 volts
260lph = 68.69 Gallons
Gas = 6.2 lb / gal
260lph / 68.69 gallons = 425.88 lb / hr
80% = SAFE = 567.84 fwhp using .60 BSFC (lb / hr x 80%) / BSFC
482.67rwhp / 2x Pumps = 965.34rwhp / 3 Pumps = 1448.01rwhp using 15% drivetrain loss

- Denso Supra in tank pump
260lph @ XXpsi @ 12 volts / 290lph @ 43psi @ 14 volts
290lph = 76.61 Gallons
Gas = 6.2 lb / gal
290lph / 76.61 gallons = 474.98 lb / hr
80% = SAFE = 633.31 fwhp using .60 BSFC (lb / hr x 80%) / BSFC
538.31rwhp / 2x Pumps = 1076.62rwhp / 3 Pumps = 1614.93rwhp using 15% drivetrain loss

If someone gets me the LPH at voltage for the 044 I'll do the math and you can get a straight comparison with actual numbers.

You're comparing apples and oranges. You quote flow at 58 psi for the W255 but 43 psi for the Denso ?? You need to use flow rate at a common pressure for a true comparison.

B044 is the blue line in the chart below:

http://www.turbobuick.com/forums/e85...ml#post2532768

I'm aware of that, but you find the denso numbers at 58psi. Trying to compare all of the different pumps with different ratings is hard. If I couldn't find the information I just figured it out with what was given and moved on to the next pump. When I put this together a while ago I couldn't find them at all. That is a decent link though with the Racetronix charts.

Here you go:

http://www.turbobuick.com/forums/e85...ow-graphs.html

Comparing one static operating condition is usually not very helpful. Looking at an entire characteristic curve conveys much more information.

The only time you need a curve is on a boosted application where the pressure against the injector is constantly fluctuating. Even on a dry nitrous setup like what will be going in my Formula it is all set to 58psi and stays there regardless of what is going on. I only need the injector flow rate at 58psi, the pump rating at voltage, and 58psi. The same applies for wet nitrous or NA setups. If it was inadequate (which it isn't) I'd simply bump the pump voltage up and go from there.

Even on what I will be doing with my 93 it will all be set to 43psi. It'll be flowing 5 fuel pumps and 16 injectors through a transitionary curve. I think the only time you need the curve is when people are trying to crutch a fuel system. Basically saying, "Well, I'm jacking my 42lb injectors to 80psi, but will my pump be able to keep up?" I'd rather spend a little more money on my fuel system and know that if I over run my wastegate or something else happens my fuel system will keep up and have a safety net.

Boost reference fuel systems are the correct way to build a FI fuel system. Although you can make do with static pressure. It is not the best way to do it though.

And only a crazy person would use 5 pumps. That's just asking for a failure and engine destruction.

Use the minimum number of pumps actually supplying fuel to the engine as possible, while safely satisfying its demands.

I use a pair of 044's, but if a single had been available at the time that suited my needs, I would never have considered multiple pumps.

I may well swap them for a Fuelab though at some stage, as they seem to offer superb performance on a compact package.

The fuel pump characteristic curve tells you everything you need to know about a fuel pump's output characteristic. You can get the flow rate number at any pressure. The number you were looking for is on the curve...

I agree that using a curve is the way to go on a boosted setup unless you are building the system to not have restrictions. You don't see the drag radial guys going... "Well, I think a single XXX pump will get it done, but I have to run it at 42V and 2psi base + 45psi of boost." They're building a setup that will flow what they need it to flow and then some. You only need a fuel pump curve to crutch your current inadequate setup. I'm not talking about putting an inch and a half fuel line or 18 255lph pumps in there either. We all know roughly the limits of Xan lines and about what each fuel pump can do on our setups through the infinite amount of dyno and track testing we've seen on here.

I bought this for $300 shipped:
http://i287.photobucket.com/albums/ll159/veee8/001.jpg

That's why I will be running 5 fuel pumps. Two in one tank, those three in the other. LED light to indicate each pump is running under boost. I want something that will sound, drive OEM, and provide the performance I need on a budget. Five walbro pumps fits that description. There's not a fuel pump out there that can supply 1000 and / or 1500 rwhp with the perfect manners of a 255 pump.

I have most if not all of the fuel system and electronics figured out how everything will work together. The only variation may be switching to an A2000 on the second fuel system, but I'm not sure if I'd want to deal with the noise or if it could take running at 3ish V for an extended drive. That I do need to figure out at some point, but I have a while to do so.

I like the 044 pumps. I'd like to see someone make two of them fit in the tank using the stock equipment. I doubt that'd happen as they're pretty large, but that would be a super nice setup and support a ton of power.

I'm not knocking that as it is good information, but it is a graph drawn on a piece of graphing paper. The numbers aren't exactly the most accurate. I give the guy an A for effort, but I'd rather have a table with XXpsi = YYYLPH, XX+5psi = ZZZlph. The guy obviously has the information. That'd be like you asking me for a nitrous jet list, I paint it in water colors, take a picture, and send it to you. It might get the job done, but there is a better way to do it.

So how exactly can an LED light prove each pump is running and supplying adequate fuel ?

And if it was possible, who the hell is going to sit watching LED lights in a car making 1000+ hp when racing ?

Nobody. And they certainly wouldnt be able to respond fast enough to do anything about it.

044's are good, but they wont support much over 1000bhp as a pair anyway. Although that seems to depend where the power is measured.


The Fuelab pumps seem to offer setups that can supply 1000+ with ease, and then some.

But if fuel demand really is above and beyond one or two pumps, just fit a mechanical pump. There certainly is no thinking required. Its very easy to know whether it will work or not.

"The Keep It Simple Stupid", approach should never be overlooked. Your's goes way beyond anything simple. Good luck with a very flawed approach though

I agree that it would be difficut to keep track of the LEDs, but isn't as difficult to watch gauges? People still have them in their cars. I'm planning on having the light come on with the fuel pump relay receiving power. If a pump is at least getting power you should assume it is working. If your pump isn't working with voltage there isn't going to be anything that'll save you at that point.

I've heard bad things about the fuelab pumps:
It's not a flawed way of setting up a fuel system. There are plenty of people running twin in tank 255 pumps. I'm just adding a complete second fuel system that'll run three pumps. Fuel system 1 on while two is only pressurizing the rails at a low voltage. Fuel system 2 ramps up and takes over completely and fuel system 1 turns off. At minimum I'd need two extremely large, noisy, and expensive pumps. Like you mention there is more than one way of doing things.

We all know what assumption is...

As you well know, you cannot assume that a power supply, means any fuel actually flowing, let alone enough to feed the engine.

It's the very reason that although I use two pumps, they use one relay, and one fuse. At least if any aspect of the power supply is suspect, both pumps should stop.
There are no check valves. So if one pump fails, I would hope that immediately fuel pressure will drop to a level that wont allow the engine to run...and not get damaged.

I really didnt want to run multiple pumps, but at the time, I didnt believe there was a single pump that would fulfill my requirements.


Not good to hear about the Fuelab though. I guess I'll hang fire on that, and wait for more feedback on them.

They are as accurate as the test methodolgy will allow, translated to a plot.

Thank you
You do realize there are production tolerances, right? Take ten pumps, check them all at XX psi and none of them will read exactly YYY.YY lph. In fact they will all give you a different number. When a manufacturer gives you a table (or graph) of flow vs psi, it's usually an average of a statistically significant number of individual units, or a worst-case tolerance stack-up of the worst expected performer (which they hope to show will meet performance requirements, which means any other pump will do better than the requirements). So really, a table can overspecify a pump's characteristic because no two pulled off the production line are exactly alike

That makes sense the way you have them wired. How large of a fuse are you running on the two pumps considering the amp draw? That may be the way to go on the second fuel system considering the transitionary period would go lean.

How long have you had the dual 044s running? On a large single pump I know a lot of people like the magnafuel stuff. You might want to check them out. I know they're rated for continual voltage too so you can cruise with them.

If you did that I commend your taking the time to put out something useful.

You kind of answered your own question though. If you are making a graph you need the plot points from a table to make the graph. If the plot points from the table are averages of production tolerances or an overspecification your graph will show those same characteristics and so will anything taken from it at an undefined value. Obviously, that is like you say, "As accurate as the test methodolgy will allow," but all that we can really work with.

I'm sure statistically we could take an equation to figure out the average of a value between two points. We did it in my old statistic class, but I really don't remember much from that class. Though getting a statistical average between two points with production tollerances and possibly invalid data are you really getting accurate information? You say that we don't really need a static point, but in most instances most people aren't running a boosted application and would prefer to see a static flow rating. I'm sure that's why most fuel pump manufacturers put out ratings at 43 or 58psi where most applications will run at. To put out a rating at 2 or 99 psi might not help a ton of people. On the other hand though if we are only lookng for one static flow rating why try to theoretically calculate hp ratings from the when we can look at the tons of examples on this site and many others of what someone can do with say a single 255lph pump, A1000, 044, etc.. I'd rather take real world in car test results than theoretical calculations any day although as you've seen I enjoy figuring out what we should see out of a pump at .XX BSF, YYpsi, and ZZvoltage.

30A fuse, running for about 4 years now. No problems whatsoever.

The Magnafuel etc pumps are too big physically for what I want, and would require a lot of work to install.

I dumped an A1000 in favour of the 044's for that reason, plus IMO the 044's are better. Although my A1000 was first used around 2002, so wouldnt be of the same capacity of the more modern versions.

Either way, its physical size was the problem.

I want a pump I can mount underneath my tank, so it doesnt intrude into luggage space in the trunk where my fuel cell is located..
And pretty much anything over 2.75" diameter, wont fit. Hence the 044's whilst tight, are ideal.

Actually there is. The external Pierburg 7.00228.51.0 ("360 lph") is from the SL55 AMG. If you look at it's flow vs pressure curve, and pick off the one static point you are interested in, it will do 88 gph at 58 psi (13.5v). with a BSFC of .5, that enough fuel for roughly 1000 hp. And you get OEM Mercedes reliability with Mercedes quiet. They are around $250.

Given modern Mercedes....I think I'll stick with the Bosch lol A lot of those "German" cars....contain a hell of a lot of cheap foreign parts.

Bosch is "German"

And lots of parts on modern Merc's are most certainly NOT German. Which is my point.

People think they are buying reliable German engineering, when in fact lots of parts are cheap foreign shite

If you've gone for years without an issue I wouldn't worry too much about it. That's a pretty good track record. What makes you still want to switch pumps?

I may end up wiring my second fuel cell as you've stated with a single fuse for all three pumps. That way if it isn't powered I'll at least have a little while to notice the failed transition. I have another fail safe method in mind, but haven't figured out all of the details just yet.

I may possibly stand corrected even though it is an external pump. I'll look into it as I've never heard of those before. Your BSFC is a little conservative for a boosted setup, but they do sound nice especially for $250 a piece.

I think that is the truth about a lot more things than Mercedes. Pretty much everything is being outsourced these days.

On an unrelated note we just had about 60 engineers, sales reps, and the COO of Mercedes stay at my hotel for a week and bring eight new 2012 models with them. We had to shut our parking lot down and let them have the whole thing which they promptly baricaded and enforced with two armed guards.