Oh it does make a mess all right. Fuel spraying out at 60+ PSI gets everywhere. At least it isn't oil ! That would be a mess. I washed the engine thoroughly, first soaping it and then rinsing.

 

http://www.turbodieselregister.com/f...=146911&page=3

"In a revision to Superduty`s sytem, he stated that a second pressure gauge in the return bypass would be very useful. I agree."

Huh ? I don't recall typing that anywhere ?

"Your using the Holley Blue in conjunction with your stock lift pump, correct ? It is my understanding that Superduty`s method doesn`t use the stock lift pump, it eliminates it, therefore reducing the heat that you are inducing into your system by adding a second pump."

The heat build up due to excess pumping is irrelevant. It is trivial compared to the amount of heat the injection pump will generate.

If someone has a membership over at DTR, could you post a link to this post so they can see that we are discussing their comments.

"The holley blue does flow 100 gph, but at what psi ??? No one can seem to find a flow chart for the holley blue pump. If it only pumps 30gph @ 15psi, what good is it ?"

Holley info is here: http://www.holley.com/types.asp?type=76

The Blue pump is 12-802-1. As near as I can guess, it outputs less than 75 GPH at 15 PSI.

"hmmm, never thought of that. I use walbro pumps in most of my cars. right now there is a 255lph pump in my race car. which Im not sure if it is larger or not thatn the stock ford pump, I would beleive it to be. and they are redily available for under 100$"

The Walbro has higher output than the stock Ford pump (Bosch). The Walbro will also run and last at higher pressures than the Bosch.

 

Superduty, You sure have stayed adamant on your idea here. I think you would be much better off hooking up a flow meter on the supply vs. the return to show what the actual gpm's that are required for the CR than guessing. Your assumptions of required gpm is wrong. I make a mechanical system for the Cummins as well as the Dmax that I mentioned in my earlier thread. The way I see it the Walbro is nothing more than the newest flavor of the month, it is still just another electric pump.

 

"I think you would be much better off hooking up a flow meter on the supply vs. the return to show what the actual gpm's that are required for the CR than guessing. Your assumptions of required gpm is wrong."

The actual amount of fuel the engine is using is right on. BSFC is BSFC.

I've guessed on how much fuel is going through the CP3 for cooling purposes, but I don't think I am far off.

The other thing is that people are running these engines with 95 GPH FASS and 110 GPH Holley Blue pumps. The Walbro puts out as much or more fuel than the Blue pump does at any sort of pressure (ie 15 PSI). If they run it, then so should the Walbro.

I am not hooking up flowmeters. I've done way more than my share on this already.

If you know how much fuel the engines are using, then tell us.

"The way I see it the Walbro is nothing more than the newest flavor of the month, it is still just another electric pump."

Go back and read what I have written. The Walbro is a high pressure, fuel cooled gerotor pump. Night and day difference from a carburetor pump.

 

Superduty,

First, thanks for taking so much time to explain fuel pumps to all of us. I know you didn't want to get dragged in this deep, but some of us are watching and learning so it really is worth it. I have no axe to grind against the FASS or Airdog systems other than their prices, and my preference for a liquid cooled pump vs air cooled.

Could you explain the pros/cons of the CP3 bypass line vs using a regulator. At first glance it seems the bypass line only is simpler and is one less thing to go wrong.

With a bypass line setup, what kind of pressures would the stock filter housing be seeing? My concern is what would happen if a bad tank of fuel clogged the OEM filter. Is there potential for the high pressure Walbro to blow the filter to pieces sending debris into the CP3? Or would fuel start flowing backwards through the bypass line before that would happen. Your earlier problem with cracking the bowl cover is why I'm concerned.

Even though the Walbro seems like a solid pump, due to the lower price I'm considering a design using two Walbro's running in parrallel. They could either be running together (in which case the relay would probably need to be upgraded). Or, the spare pump could be plumbed but powered through a toggle switch in case the main pump dies. It seems that the parts for such a redundant Walbro system would still cost less than the FASS-2. A third possibility is to just carry a spare Walbro under the seat, but with my luck if a failure did occur it would be at night in a rain or snowstorm, hence my desire for dual-pumps.

If you want to me to post a link over at TDR, let me know. I'm MFALKINHAM over there.

- Mike

 

"Could you explain the pros/cons of the CP3 bypass line vs using a regulator. At first glance it seems the bypass line only is simpler and is one less thing to go wrong."

The bypass relies on the fact the CP3 has a built in lift pump. The bypass system puts all the Walbro's fuel (about 80 GPH) going by the CP3 inlet and lets the CP3 take as much or little as it likes. The bypass line is chosen to be a bit restrictive so that the CP3 inlet is slightly pressurized.

Some people prefer to pressure feed their CP3s. Putting a regulator at the CP3 does the same thing as the bypass but with more pressure. The thing I like is that all the lift pump's flow is going by the CP3 inlet. That minimizes the chances that it starves.

"With a bypass line setup, what kind of pressures would the stock filter housing be seeing?"

I saw 6 PSI pre filter on my "Ferd". A Dodge may be different.

"My concern is what would happen if a bad tank of fuel clogged the OEM filter. Is there potential for the high pressure Walbro to blow the filter to pieces sending debris into the CP3?"

Yep. A pressure gauge should be run pre filter to monitor the backpressure.

"Or would fuel start flowing backwards through the bypass line before that would happen. Your earlier problem with cracking the bowl cover is why I'm concerned."

The only way fuel would go backwards in the return line is if the Walbro would be unable to push fuel through the filter and that would take 100 PSI on the part of the filter. The filter housing will crack prior to that.

A simple check valve could be put in the return line to prevent backflow in it. There might be such a valve in the stock Dodge trucks already. I don't know.

"Even though the Walbro seems like a solid pump, due to the lower price I'm considering a design using two Walbro's running in parrallel."

OK.

"If you want to me to post a link over at TDR, let me know. I'm MFALKINHAM over there."

I'm interested in opening up the whole fuel pump debate. I don't care who "wins". If there is something better than the Walbro (aeromotive?) then so be it. If the TDR people aren't aware of this discussion, by all means invite them in.

The Walbro 392 flows 255 L/hour or 85 ish GPH. It will run at whatever pressure the regulator is set at. If you want less flow, there are other similar but smaller Walbro pumps available.

The regulator needs to be a returning type. It has to vent excess fuel into the return line or the Walbro will run at 100 PSI. (Until the filter housing blows...)

The BSFC for the ISBe is about 0.390. 325HP x 0.390 lbs/HPHR / 7lbs/gal = 18.1 GPH, plus what the CP3 needs for cooling and lube. Say 25 GPH.

 

Superduty,

Sorry no real order here as I am just writing this during my break.

It has been my experience that every electric fuel pump flow rating is an open port rating. It is a sales thing. Most the pumps you mentioned thus far are taken a beating from Walbro in the car market forums lately. So it is easy to see why it is now the flavor of the month. It is good to see others willing to try something new. But there are some misconceptions going out on this one.
The only CP3’s that I have heard of failing where the ones that where modified. CP3’s have proven to be much more reliable than the VP-44 and more forgiving as a 44 wouldn’t tolerate 60 psi of pressure.
This forum had a thread about using a bung w/ fitting on the bottom of the tank to lower the inlet flow restriction to the pump. Yet after all the explanation the answer is still you must need more pressure and flow. Peirs’s truck just dyno’d 685hp with a FASS a couple weeks ago and it was reported he had good pressure through out the run. Are you making that much power? If not this should be a good example that a FASS even if it falls off volume wise quicker than the pump you listed is more than worthy to feed a CR?
I feel fuel volume should be related to need. Not constant pressure/flow like an electric pump. As far as pressure vs. volume, the mechanical pumps I use run 35 percent above the pressure chart you posted at all pressures until 100psi only because I felt no reason to test above 100. Mechanical pumps only consist of 10 parts, very similar to the oil pump in the engine. They are brutally simple and use carbon steel gears powered by a ½”steel shaft. Being that the engine powers them they are ideal for pumping fuel without making the heat of an electric. And unlike electrics there are larger pumps available with the same design capable of up to 23 gallons per minute. Which would be quite silly but it proves the point that the mechanical pump is already to rock to the next level.

Now for a few boring questions.

Is the Walbro pump rated for diesel? I personally think Stoddard was used since it is a thicker fluid and thus will make higher pressure than gasoline.

What is the in-rush/initial amp draw of this pump? I ask because if it is more than the stock pump and you don’t use a relay… just like the 2nd gen trucks the power that feeds the pump is unfused directly from the ECM. And others have found too much draw will kill the relay inside the ECM.

Has your truck been outside during a freezing night since this pump was installed?


As for the flow test I did them with a stock pump (not that that matters.) And the numbers where way way below your estimate. Since you don't feel like doing a flow test I understand completely as I don't want to share my R&D numbers.

As for the stock filter housing cracking at 100 psi. Not true but the only way you would know that is if you are hard headed enough to make/buy a billet fuel filter cap, it was my finding that the OEM seal/cap leaked anything above 30 psi.

Like I said above it is good to see guys trying new ideas. Though it does suck you feel the need to use the F word (Ford) in your post. I really hope their 6.4 is better than their last two attempts at building a diesel.

 

"It has been my experience that every electric fuel pump flow rating is an open port rating. It is a sales thing."

I agree with that. We would thus give the Walbro a rating of 85 GPH.

"Most the pumps you mentioned thus far are taken a beating from Walbro in the car market forums lately. So it is easy to see why it is now the flavor of the month."

Sure. Except that some of us have been running it for 5 years. It has been a long month ! The Walbro 392 is thus older than the FASS or the BullyDog. And if you count the car sales, the Wablro probably outsells those pumps by 10:1. So the Walbro is more than a fad or "flavor of the month" as you call it.

"The only CP3's that I have heard of failing where the ones that where modified. CP3's have proven to be much more reliable than the VP-44 and more forgiving as a 44 wouldn't tolerate 60 psi of pressure."

As far as I am concerned, the jury is out on the CP3 and if it does fail it could be due to debris or fuel. A number of CP3s experienced seal failures in 3rd Gen Engines and Drivetrain when the weather got cold. I suspect but cannot prove that those failures were lift pump related. Time will tell.

The maximum pressure limit of the VP44 is irrelevant. DO YOU PEOPLE READ MY POSTS ? HOW MANY TIMES DO I HAVE TO SAY THAT THE WALBRO WILL RUN AT THE PRESSURE THE REGULATOR IS SET FOR !!!!!!

The Walbro is CAPABLE of 80 or 100 PSI. Most owners will probably set it to run at 15ish PSI at the injection pump, which probably means 20 to 25 PSI at the lift pump, depending on filter cleanliness, etc.

It is just like your Cummins. I makes 250 or 305 or 325 or whatever HP it is rated for. Does that mean it ALWAYS runs at that power ? NO. Same thing with the Walbro.

"This forum had a thread about using a bung w/ fitting on the bottom of the tank to lower the inlet flow restriction to the pump."

I don't have a clue what you are talking about and it doesn't matter as far as the Walbro is concerned. The Walbro has no problem with getting enough flow. Being that it is rated for 80 PSI, it has enough pressure to push or pull way more fuel than is needed.

"Yet after all the explanation the answer is still you must need more pressure and flow."

NO! I am arguing the following:

a) one DOES NOT need a 150 GPH FASS to feed these engines

b) I feel it is advantageous to run the full lift pump flow through the stock filter and by the injection pump, not divert a bunch of fuel back to the tank at the lift pump. Thus my setup takes more lift pump pressure because it pushes more fuel through the stock fuel filter and lines.

c) the pumps people are now selecting are operating on the verge of being over loaded. Why not select a pump that operates at 25% of its rated pressure rather than 110% of its maximum pressure ?

At this point I have to say that I am getting tired of repeating the same arguments OVER AND OVER to people who are not reading what I have previously written.

"Peirs's truck just dyno'd 685hp with a FASS a couple weeks ago and it was reported he had good pressure through out the run."

Good for him.

"Are you making that much power?"

NO. And what would it prove if is did ? I've gone to great lengths to show that even the Walbro delivers way more fuel than even this engine would require. People need to stop believing the BS that the spin doctors put out there regarding fuel pump requirements and start using a scientific approach to figuring out what they do and don't need for a fuel pump.

685HP x BSFC of 0.5lbs/HPHR / 7 pounds per gallon = 49 GPH. At 20 PSI, the Walbro delivers 70 GPH.

That is what people need to know and understand. They don't need to to know what brand of pump he used, nor how big his lines "needed to be". They need to understand the numbers and the issues.

It might prevent situations like this:
https://www.dieseltruckresource.com/...ad.php?t=89977

 

"If not this should be a good example that a FASS even if it falls off volume wise quicker than the pump you listed is more than worthy to feed a CR?"

That doesn't prove a darn thing. A FASS, probably rated at 150 GPH, probably with special lines and a bunch of fuel system voodoo like special banjos and some sort of a special kit feeds an engine 49 GPH of fuel. WOW ! We are supposed to be impressed by that ??? That is supposed to prove something ? Give me a break !

Anyone that understands diesel engines can sit down with a calculator and say that engine needs 49 GPH (plus lube can cooling flow) and select a decent pump. And if they want they won't need to spend $600 and they won't need special lines or voodoo connectors or any of the rest of that crap. No magic. No hero worship. You can buy it on Ebay for $110. They will ship it for another $9. Get it ?

All the engine needs is 49 GPH (plus cooling and lube flow). It doesn't need 150 GPH. It isn't friggin magic. It is magic if you try to do it with the wrong pump and then set about compensating for that. But lots and lots of over the road trucks make 5-600 HP these days and they are not running a 150 GPH FASS fuel pump.

"I feel fuel volume should be related to need."

Me too.

"Not constant pressure/flow like an electric pump. As far as pressure vs. volume, the mechanical pumps I use run 35 percent above the pressure chart you posted at all pressures until 100psi only because I felt no reason to test above 100. Mechanical pumps only consist of 10 parts, very similar to the oil pump in the engine. They are brutally simple and use carbon steel gears powered by a ½"steel shaft."

Oh man... give me a break. 49 GPH at 20 PSI is less than 1/25th of a HP. It is less power than a food processor. Does your food processor use an electric motor or a chainsaw motor ?

Why would a perfectly sane truck owner feel the need to replace a simple, $110 electric pump that will run for years and years with a belt driven mechanical pump ? Can you give me any sane justification for that ? Do the gasoline EFI engines run belt driven fuel pumps ? NO. They run electric fuel pumps.

"Being that the engine powers them they are ideal for pumping fuel without making the heat of an electric."

Did you say heat ? Are you saying heat is an issue ? Are you trying to tell me that your belt driven fuel pump, the one with about 50 pounds of belt side thrust on 2 bearings is going to heat up less than the 25 watts of wasted electrical power the Walbro *might* have ? Don't even start on that topic.

"And unlike electrics there are larger pumps available with the same design capable of up to 23 gallons per minute. Which would be quite silly but it proves the point that the mechanical pump is already to rock to the next level."

The next level ? Please show me ANY Cummins engine that needs more than 100 GPH. If you could find me such an engine my response would be to put 2 Walbros in parallel. It would cost about $250. They'd be good to 80 PSI, as usual. Would take about an hour to install. No belt. No belt drive. No cutting the fan blades.

"Is the Walbro pump rated for diesel?"

Yes.

"I personally think Stoddard was used since it is a thicker fluid and thus will make higher pressure than gasoline."

Put a Walbro on a Cummins and start turning up the pressure. I'll bet you wreck something before you stall the Walbro.

"What is the in-rush/initial amp draw of this pump?"

Probably depends on the whole fuel and electrical system dynamics. Is there a backpressure on the pump to start, is the regulator open or closed ? What is the inductance and capacitance of the motor supply circuit, what are the closing characteristics of the relay contacts. What is your point here ?

"I ask because if it is more than the stock pump and you don't use a relay… just like the 2nd gen trucks the power that feeds the pump is unfused directly from the ECM. And others have found too much draw will kill the relay inside the ECM."

ECMs don't use relays for controlling the fuel pump. The Cummins ECMs do something called pulse width modulation. That is a digital power control technique and it works with transistors, or more specifically, something called an open collector output. It doesn't work with a relay. Relays don't operate fast enough. They are electo mechanical devices. PWM needs digital semiconductor devices.

"Has your truck been outside during a freezing night since this pump was installed?"

Yep. It has been out in 20 below. And it pushed fuel through the Powerstroke fuel filter at that temp at 60 PSI nonetheless. Wanna try that with a carburetor pump ? Hmmm.... (I edited this. I had 40 below here, but that would have been an exaggeration. I started the Powerstroke when it has been 20 something below.)

"As for the flow test I did them with a stock pump (not that that matters.) And the numbers where way way below your estimate. Since you don't feel like doing a flow test I understand completely as I don't want to share my R&D numbers."

So you are saying the engines are flowing less fuel than what I am saying ?

OK... this thread

https://www.dieseltruckresource.com/...ad.php?t=76473

states that the valve cover sticker, as specified by Cummins in the emissions tests, which have to be +/-5%... for a 305/555 engine that makes 305 HP at 2900 RPM has a fuel delivery rate of 114 mm^3 per injection event at WOT.

So...

114mm^3 x 2900 RPM/2 x 6 injectors x 60 min/hour = 59.5 litres of fuel per hour.

= 15.72 gallons per hour. Fuel weighs 7 pounds per gallon, so this is 110 pounds.

Our engine is making 305HP, so the BSFC is 110/305 = 0.3608 lbs per HPHR.

Now... the 305 is better on fuel than most, even better than some of the 1st gens. (Oh.. I can see the arguments starting now...) I've run this calc for about a dozen Cummins engines and they have a BSFC of anywhere between 0.350 to 0.390 at WOT at rated HP.

I'd say that my fuel requirement calculations are pretty close.

On the modded engines I move the BSFC number up because they are wasting a lot of heat out the exhaust.

"As for the stock filter housing cracking at 100 psi."

I said the LID cracked, not the housing. LID. L-I-D. LID.

"Not true but the only way you would know that is if you are hard headed enough to make/buy a billet fuel filter cap, it was my finding that the OEM seal/cap leaked anything above 30 psi."

Well.. a guy happened to install a Walbro on his 2nd gen truck this week and accidentally set the pressure to 30 PSI. He did not complain of leaks or a cracked lid. Prior to this, another gentleman ran his at 60 for a while and did crack his <plastic> lid.

I don't know what mine cracked at because I was getting my engine running at the same time I cracked it. Yes, not only was I messing with a new fuel system, but also a new clutch, transmission, throttle control (that I wired, none the less), cooling system, etc. I was experiencing sensory overload when my fuel filter lid started spewing fuel.

That was the birth of the CP3 bypass.

 

Superduty, my truck goes in this week for this mod. One last question though. I'll be running the simple bypass with a pressure gauge pre-filter to monitor back pressure. At what pressure would you reccomend to change the filter?

 

I don't know. Is your filter clean ? I'd watch the backpressure on it from clean and see how it goes up as it gets dirty.

We will have to get some experience with our filters and figure out when to change them.

 

Of corse it will have a clean filter installed when I get the work done. I think I'll try 20# and see how fast it gets there.Where I work, we monitor the vaccum side of the supply system, as all our boilers, pump engines, and gen sets have the filters mounted before the pump. We are trained to change the filters at 15-20in. of vac. so I figure 20# is a good start on the pressure side.

 

I reccomend that you put a pressure guage both before and after the filter. Reasoning behind that is you can monitor the pressure difference across the filter and know how well your filter is performing.

 

Superduty,
Well this is the largest reply I have done...

Sure. Except that some of us have been running it for 5 years. It has been a long month ! The Walbro 392 is thus older than the FASS or the BullyDog. And if you count the car sales, the Wablro probably outsells those pumps by 10:1. So the Walbro is more than a fad or "flavor of the month" as you call it. So how long has it been used in a Cummins application? It took the FASS a couple years before the threads started getting upset about it.

"The only CP3's that I have heard of failing where the ones that where modified. CP3's have proven to be much more reliable than the VP-44 and more forgiving as a 44 wouldn't tolerate 60 psi of pressure."

As far as I am concerned, the jury is out on the CP3 and if it does fail it could be due to debris or fuel. A number of CP3s experienced seal failures in 3rd Gen Engines and Drivetrain when the weather got cold. I suspect but cannot prove that those failures were lift pump related. Time will tell.
You seriously feel that the leaking seals had something to do with lift pumps? I don’t considering the leaking pumps a failure. Even the Chevy’s were leaking and as we know they don’t even use a lift pump. Seems to me that Bosh overlooked something in the seal. The maximum pressure limit of the VP44 is irrelevant. DO YOU PEOPLE READ MY POSTS ? HOW MANY TIMES DO I HAVE TO SAY THAT THE WALBRO WILL RUN AT THE PRESSURE THE REGULATOR IS SET FOR !!!!!!
That’s great so if a regulator was to stick will Walbro replace a broken VP44?The Walbro is CAPABLE of 80 or 100 PSI. Most owners will probably set it to run at 15ish PSI at the injection pump, which probably means 20 to 25 PSI at the lift pump, depending on filter cleanliness, etc.
According to your chart it is capable of over 130 psi.
It is just like your Cummins. I makes 250 or 305 or 325 or whatever HP it is rated for. Does that mean it ALWAYS runs at that power ? NO. Same thing with the Walbro.
I gave up on electric pumps a few years ago. Just like in the aircraft world I use them as a backup but I run a mechanical for a primary pump. "This forum had a thread about using a bung w/ fitting on the bottom of the tank to lower the inlet flow restriction to the pump."

I don't have a clue what you are talking about and it doesn't matter as far as the Walbro is concerned. The Walbro has no problem with getting enough flow. Being that it is rated for 80 PSI, it has enough pressure to push or pull way more fuel than is needed.
You are saying so but the required pull at higher horsepower seems to take out all but the overkill electric pumps. Your rating is nice but real world is where it is at. "Yet after all the explanation the answer is still you must need more pressure and flow."

NO! I am arguing the following:

a) one DOES NOT need a 150 GPH FASS to feed these engines
I agree but overkill has a history and piece of mind in the muscle truck world. Most resist the sickness but few stay stock.b) I feel it is advantageous to run the full lift pump flow through the stock filter and by the injection pump, not divert a bunch of fuel back to the tank at the lift pump. Thus my setup takes more lift pump pressure because it pushes more fuel through the stock fuel filter and lines.
That’s cool but even with the FASS diversion isn’t it still pushing the same or even more than your pump the way you are regulating it?
c) the pumps people are now selecting are operating on the verge of being over loaded. Why not select a pump that operates at 25% of its rated pressure rather than 110% of its maximum pressure ?
This sounds good but how did you come up with 110% of maximum?At this point I have to say that I am getting tired of repeating the same arguments OVER AND OVER to people who are not reading what I have previously written. Very simple reason so many vendors have not lived up to their claims.
"Peirs's truck just dyno'd 685hp with a FASS a couple weeks ago and it was reported he had good pressure through out the run."

Good for him.

"Are you making that much power?"

NO. And what would it prove if is did ? I've gone to great lengths to show that even the Walbro delivers way more fuel than even this engine would require. People need to stop believing the BS that the spin doctors put out there regarding fuel pump requirements and start using a scientific approach to figuring out what they do and don't need for a fuel pump.
It would prove that your pump will support that much hp. Slide rules and calculators are nice but the BS stops in the real world.685HP x BSFC of 0.5lbs/HPHR / 7 pounds per gallon = 49 GPH. At 20 PSI, the Walbro delivers 70 GPH.

That is what people need to know and understand. They don't need to to know what brand of pump he used, nor how big his lines "needed to be". They need to understand the numbers and the issues.
What we understand is he made 685 hp.
It might prevent situations like this:
https://www.dieseltruckresource.com/...ead.php?t=89977
What was the above situation?"If not this should be a good example that a FASS even if it falls off volume wise quicker than the pump you listed is more than worthy to feed a CR?"

That doesn't prove a darn thing. A FASS, probably rated at 150 GPH, probably with special lines and a bunch of fuel system voodoo like special banjos and some sort of a special kit feeds an engine 49 GPH of fuel. WOW ! We are supposed to be impressed by that ??? That is supposed to prove something ? Give me a break !
You got me I don’t know about voodoo fittings. Once again it did it in the real world. Anyone that understands diesel engines can sit down with a calculator and say that engine needs 49 GPH (plus lube can cooling flow) and select a decent pump. And if they want they won't need to spend $600 and they won't need special lines or voodoo connectors or any of the rest of that crap. No magic. No hero worship. You can buy it on Ebay for $110. They will ship it for another $9. Get it ?
What I get is you have a steak in these. That’s cool. Hero worship? No not from me. But I have respect for anyone that takes their truck to the leading edge. And in this case the pump that was used was the one that you are so unhappy with.

 

All the engine needs is 49 GPH (plus cooling and lube flow). It doesn't need 150 GPH. It isn't friggin magic. It is magic if you try to do it with the wrong pump and then set about compensating for that. But lots and lots of over the road trucks make 5-600 HP these days and they are not running a 150 GPH FASS fuel pump.
How many of them road trucks are using the Dodge Ram fuel tank? Sounds silly but you really should prove your case before selling other systems so short.
"I feel fuel volume should be related to need."

Me too.

"Not constant pressure/flow like an electric pump. As far as pressure vs. volume, the mechanical pumps I use run 35 percent above the pressure chart you posted at all pressures until 100psi only because I felt no reason to test above 100. Mechanical pumps only consist of 10 parts, very similar to the oil pump in the engine. They are brutally simple and use carbon steel gears powered by a ½"steel shaft."

Oh man... give me a break. 49 GPH at 20 PSI is less than 1/25th of a HP. It is less power than a food processor. Does your food processor use an electric motor or a chainsaw motor ? Truth is I use the chainsaw motor for my blender and yes sir it has outlasted several electic blenders.
Why would a perfectly sane truck owner feel the need to replace a simple, $110 electric pump that will run for years and years with a belt driven mechanical pump ? Can you give me any sane justification for that ? Do the gasoline EFI engines run belt driven fuel pumps ? NO. They run electric fuel pumps.
Sure that’s easy the mechanical one will outlast the motor and like I mentioned earlier it is simple to rebuild.No I haven’t noticed any EFI motors running a belt driven pump. Seems like it is mainly used in the drag racing world. I know several that wish they did though as most them cars have the pump in the tank.
"Being that the engine powers them they are ideal for pumping fuel without making the heat of an electric."

Did you say heat ? Are you saying heat is an issue ? You got me on that one I missread an earlier post. Are you trying to tell me that your belt driven fuel pump, the one with about 50 pounds of belt side thrust on 2 bearings is going to heat up less than the 25 watts of wasted electrical power the Walbro *might* have ? Don't even start on that topic.
Why not start that topic? There is no reason to set a synchronous drive systems to 50 pounds of side belt thrust. Nice twist though. And yes it will run cooler than your pump.
And unlike electrics there are larger pumps available with the same design capable of up to 23 gallons per minute. Which would be quite silly but it proves the point that the mechanical pump is already to rock to the next level."

The next level ? Please show me ANY Cummins engine that needs more than 100 GPH. If you could find me such an engine my response would be to put 2 Walbros in parallel. It would cost about $250. They'd be good to 80 PSI, as usual. Would take about an hour to install. No belt. No belt drive. No cutting the fan blades.
Cutting fan blades?
"Is the Walbro pump rated for diesel?"

Yes.

"I personally think Stoddard was used since it is a thicker fluid and thus will make higher pressure than gasoline."

Put a Walbro on a Cummins and start turning up the pressure. I'll bet you wreck something before you stall the Walbro.
Well that’s nice.
"What is the in-rush/initial amp draw of this pump?"

Probably depends on the whole fuel and electrical system dynamics. Is there a backpressure on the pump to start, is the regulator open or closed ? What is the inductance and capacitance of the motor supply circuit, what are the closing characteristics of the relay contacts. What is your point here ? Read original next sentence below.
"I ask because if it is more than the stock pump and you don't use a relay… just like the 2nd gen trucks the power that feeds the pump is unfused directly from the ECM. And others have found too much draw will kill the relay inside the ECM."

ECMs don't use relays for controlling the fuel pump. The Cummins ECMs do something called pulse width modulation. That is a digital power control technique and it works with transistors, or more specifically, something called an open collector output. It doesn't work with a relay. Relays don't operate fast enough. They are electo mechanical devices. PWM needs digital semiconductor devices.
Ok if you goto the wiring diagram 8w-30-48 you can see the circuit. Inside the ECM they call it the Fuel Pump Relay Control. But if you reread the comment above, I am asking if it is ok to hook up the pump to the factory wire or is a relay needed. If it is not needed will Walbro buy a replacement ECM if it takes out the semiconductor you spoke of?

"Has your truck been outside during a freezing night since this pump was installed?"

Yep. It has been out in 40 below. And it pushed fuel through the Powerstroke fuel filter at that temp at 60 PSI nonetheless. Wanna try that with a carburetor pump ? Hmmm....
Hmmm How did were we doing it before you?
"As for the flow test I did them with a stock pump (not that that matters.) And the numbers where way way below your estimate. Since you don't feel like doing a flow test I understand completely as I don't want to share my R&D numbers."

So you are saying the engines are flowing less fuel than what I am saying ?
Yes on the 04 that I tested the numbers where lower, though there are other factors that may of contributed to that.

OK... this thread

https://www.dieseltruckresource.com/...ead.php?t=76473

states that the valve cover sticker, as specified by Cummins in the emissions tests, which have to be +/-5%... for a 305/555 engine that makes 305 HP at 2900 RPM has a fuel delivery rate of 114 mm^3 per injection event at WOT.

So...

114mm^3 x 2900 RPM/2 x 6 injectors x 60 min/hour = 59.5 litres of fuel per hour.

= 15.72 gallons per hour. Fuel weighs 7 pounds per gallon, so this is 110 pounds.

Our engine is making 305HP, so the BSFC is 110/305 = 0.3608 lbs per HPHR.

Now... the 305 is better on fuel than most, even better than some of the 1st gens. (Oh.. I can see the arguments starting now...) I've run this calc for about a dozen Cummins engines and they have a BSFC of anywhere between 0.350 to 0.390 at WOT at rated HP.

I'd say that my fuel requirement calculations are pretty close.
Works for me.
On the modded engines I move the BSFC number up because they are wasting a lot of heat out the exhaust.
Sure you can't find a formula for that one too?"As for the stock filter housing cracking at 100 psi."

I said the LID cracked, not the housing. LID. L-I-D. LID.
Well if you goto thread #247 you wrote that the filter would take 100 psi of pressure but the housing would crack prior to that.
"Not true but the only way you would know that is if you are hard headed enough to make/buy a billet fuel filter cap, it was my finding that the OEM seal/cap leaked anything above 30 psi."

Well.. a guy happened to install a Walbro on his 2nd gen truck this week and accidentally set the pressure to 30 PSI. He did not complain of leaks or a cracked lid. Prior to this, another gentleman ran his at 60 for a while and did crack his <plastic> lid.
Believable as I only pressurized one filter assy and like I stated above it leaked from the cap at 30psi. I didn’t see the need to make a mess.I don't know what mine cracked at because I was getting my engine running at the same time I cracked it. Yes, not only was I messing with a new fuel system, but also a new clutch, transmission, throttle control (that I wired, none the less), cooling system, etc. I was experiencing sensory overload when my fuel filter lid started spewing fuel.

That was the birth of the CP3 bypass.

All righty then, like I said earlier it is nice to see new ideas / mods. Even though you may not like what others are running several others too have fixes at the hp range you are at and been running them longer in this application. I have watched several new products come into this market. I remember when FASS was going to save the day by getting rid of micro-bubbles. Then the Powerdog was going to make that look like a POS. Now we have the Walbro, that’s cool. Instead of dazzeling us with your overview step up and fully test it in a few different Cummins. Actions speak much louder than words here. FWIW I hope it works out for you guys. But so many already have a proven solution that works for them that they may not be interested in a new flavor.
Gotta get to work,

Opie