Young Performance

CcanDo,
It seems you know a lot about the Dodge problem. Mine got me this past Christmas eve driving to New Orleans to spent Christmas with our families. We found a dealer ship in Bum Phuck Nowhere to fix it on Christmas Eve. They charged me $1800 to put the new lift pump in the tank and at the time, I was glad to pay it.
Eddie

stevesxm

your examples all make perfect sense. and my real world experience above 900 hp is zero. i think the key to any of this is always to simply solve what the problem actually is and the rest will take care of itself. if you have 1500 hp then you need x lbs of fuel per hour to feed it. that defines the pump output required. once you know that you figure out how to get that many lbs x 2 out of the tank , the specifics of which are determined by the physical layout. you know as a matter of fact , that vane pumps don't lift well so you scout around and find a pump that lifts what you require and size the pickup tube accordingly. and you are done.

we aren't going to the moon and we aren't doing anything that hasn't been done a trillion times by a trillion guys and we aren't dealing with a lot of different variables. the answer is , as always " the combination" . for example... i use a carter electric pump for a lift pump. i don't remember the numbers but i think it was 5 gal/min at free flow. that lifts roughly 30 " thru a 3/8 tube... all factory hardware. a 3/8 tube has an area of .11 sq in. . now if i put a 5/8 pickup tube in there the area becomes .305 sq in. thats 3 times the area. that means that that pump now has to lift 3 times the weight of fuel 30" that it did before. maybe it can, maybe it can't... but the point is that if it CAN'T that means i have a problem on low fuel level which is completely self inflicted. . does that mean the pump is bad ? no. it means that the combination of components that i have selected for the installation is not correct for the installation. the error lay with my selection of a pick up tube that is 800 % larger than what my motors need.

if i had 1500 hp per side then maybe the 5/8 tube might be necessary along with a suitable pump that can lift that particular column of fuel.

thats all im saying. every element in the system needs to be correct for the application. everything " more" than that is just wrong for some reason. you can often get away with it and things seem to work ok but if done properly the results would be better... less heat, less electrical strain, relief valves not working at 100 % open 100% of the time... that sort of thing.
and often you DON'T get away with it. you change something based on some folklore or voodoo and end up with unintended consequences that you then start chasing like ghosts.

keep it simple. don't invent a problem just so you can invent a solution.

CcanDo

A couple more points:

1. Fuel doesn't know the pickup tube ends at tank top. The pickup tube effectively ends at the high point in the fuel line attached to the tank mounted pickup tube. And, only then if the distance to pump from that high point is close by,all subject to fitting restriction. As the fuel line inside diameter would increase after the tank mounted pickup tube, more suction will be required.

2. Stainless Steel Industry standard has 1/2" tubing from 0.035" to 0.083" wall thickness, creating an ID of 0.430 to 0.334". The flow difference is substantial and augmented by PSI. Note: as a flared sharp edge or sharp 90* fitting exists that area becomes an orifice.

3. The Seal Industry refers to gasoline as sour, meter and aviation. Acceptable seals for all three is either Leather (Thiokol impregnated ) , Teflon 120 or Viton. However, Viton may be questionable for high Ethanal content.

CcanDo

Eddie, the Dodge Cummins is an example of how a simple problem has been complicated for their engineers and frustrating for their customers.

Ford and Gm has had their challenges as well.

I'm of the opinion, the safest boat fuel system includes an in tank pump and engine and/or electric pump.

We opened up the aluminum tanks and fitted oversize aircraft fill caps to allow mopping access at the tank floor. The cap is large enough to allow installation of an electric pump.

Presently, fuel can go to an engine driven CV billet pump (which we helped design) or an electric pump if the engine driven pump should fail. Beyond the emergency safeguard, the electric pump is used to prime, then come on automatically at 3,000 RPM holding 7 PSI by itself or in concert with the engine driven pump. The electric pump will also operate when switched to "ON".

BenPerfected

Geez Cat.... NASA has been having fuel problems on the Space Shuttle program. I am absolutely certain you could help them with improving the reliability of the entire program. I know they still have an adhesive concerns with the tiles at re-entry.
I do really like the our CV fuel pumps (7 lbs green spring), should have know you had a part in the design...thanks!

CcanDo

Ben, have a little respect for your elders, you might be old and crazy someday, yourself.

As for NASA, that crew seems have their hands full, at least with shuttle craft. So, shall we joint venture that deal ?

Glad you like your pump...kind of pricey, now Holley is offering a billet at a similar price. Have you seen anything about the CV you didn't like ?

BenPerfected

When we bought our CV FP's, they didn't offer them with the overflow fitting in case of a ruptured diaphragm. We drilled and tapped ours. Today, I think this is either an option or they now ship them with a 1/8 NPT plug for easy rigging.
When we got our CV pumps a few years ago, we ordered them with an set of extra springs. We never changed the springs until this last winter. Our fuel pressure is now back to a rock solid 7 lbs.
If you have 600- 800 HP carbureted and want simple without a regulator or return line, I would argue the these pumps are low installed cost and easy to rebuild.

stevesxm

with all due respect, the configuration is , for all practical purposes, irrelevant. it is simply a force and weight balance. if you make 1 lb of suction force you can raise 1 lb of fuel. if the tube is small, it can raise it a long way because 1lb of fuel extends a long way up a small tube. if it is a large tube you can raise it only as far as 1 lb of fuel will fill the tube and no further. bends and necks and percieved restrictions will effect ultimate flow rate only as they will create internal drag with uses up energy etc etc.. and it all slows down but realistically these considerations shouldn't be a factor in an intellegent design. if you design a system that has 100 feet of line, 25 right angle bends, 6 filters and dead squillel in it, then yes... you will need a much stronger pump than if you kept the pumps very close to the tank and kept the suction lines as short as possible and sized appropriatly for the job... and then left the pressure side of the pump do the job that it is much more able to do which is push the fuel upstream.

this is the old anchor joke... you know the one, ... the sea scout is being tested and the instructor asks " what do you do when a storm comes up from the south ? " throw out a southerly anchor the scout answers... what do you do when a storm comes from the north ? " throw out a northerly anchor... what do you do when a storm then comes from the west ?" throw out a westerly anchor the scout says... then the instructor says " well tell me where you are getting all these anchors from" and the scout says " the same place you are getting all the storms.

the answer to this question is always the same. and no matter how many bizzare or inefficient configurations and scenarios that are suggested as reasons why one solution or another may not work, it always comes down to the same thing and nothing else...

you need a pump that will raise ( at a minimum ) the WEIGHT of the fuel in the total plumbing before the pump, to the maximum height that the pump is from an empty tank at a sufficient rate to supply the motor at wot. no more. no less.

that leaves you no margin for failure or safety but thats the answer. and its always the answer no matter what the hardware you choose to emplyy or the logic that drives you to select it whether that logic is correct or not. if you figure you need a 4" pick up tube because you absolutely have to have a flow rate of 750 gals per minute then that selection forces you to also select the pump that will raise that column to the height of where the pump is to be located. the two componets are inextricably linked in the selection process.

2. Stainless Steel Industry standard has 1/2" tubing from 0.035" to 0.083" wall thickness, creating an ID of 0.430 to 0.334". The flow difference is substantial and augmented by PSI. Note: as a flared sharp edge or sharp 90* fitting exists that area becomes an orifice.again... the size of what they make is meaningless. all that matters is the id relative to what you need as a function of the published flowrates for that dia at the pressure you want. if you need, 30 gal/hour at 42 psi, you go to the chart and it tells you the size or you can do the math yourself. and then if you put a lot of bends and kinks and 90's in it , then you allow for those restrictions in the sense that they really do change anything and select accordingly.

MER Performance

I have been using nothing but, the CV Products billet Fuel pump on all my builds that require a mech. pump either on the block or pump mount. The only problem they have had with them is the check valve disk,wearing the edges out and the disk gets off center. I agree with CcanDo, Issues with electric vane pumps trying to pull a vac. is not the proper application of use. All the boats we are dealing with are guility of this. Pumping to a sump tank is far better or installing it in the fuel tank the eletric pump as on aircraft is the correct installation. An access panel can be install in the tank, getting the marine oems to do it, thats the hard part. Now the cost of the fuel pump is going to go up, since it will be submerged in fuel. You thought marine prices are high, wait until you get the a/c pricing. I'am a A&P Mech, took that knowledge to what I do today.

MER Performance

CcanDo, I knew there was more to you, when you questioned me on my thread: Hi Rev Hydraulic Lifters & 20w50 Oil. You are serious, you helped CV develope that pump. They always make it sound like all the engineers are in-house.BIG PAYROLL for Mr. Vickers, thats why; the prices are so high.