The Diesel Garage banner

High Flow fuel pumps

5K views 47 replies 19 participants last post by  Lowboy 
#1 ·
What is everyone running? We did 2 stock pumps in tandom at BTS but I'm dropping 40lbs of fuel pressure at WOT. I need to figure out the best way to solve this, I'll let the system we installed on the truck incase of a failure I'll be able to get where I need to be.
 
#2 ·
I don't have any experience with them but I think most upgrade to an Aeromotive pump if changing from the stock one.
What does your current system consist of?
By tandem do you mean both pumps drawing from a 1/2" hose or dual 5/16" then back into a 1/2" hose? The reason I ask is with 300 hp I cant imagine 2 pumps not keeping up. Maybe you have a restriction somewhere between the pumps and the fuel inlet to the heads.

I recently installed a complete fuel system on my OBS and with stage 1 injectors I don't drop more than 2 psi at WOT. This is with 1 stock SD pump.
 
#3 ·
Diesel Dog said:
What is everyone running? We did 2 stock pumps in tandom at BTS but I'm dropping 40lbs of fuel pressure at WOT. I need to figure out the best way to solve this, I'll let the system we installed on the truck incase of a failure I'll be able to get where I need to be.
What you need is a lift pump feeding a high volume pump. Talk to Dennis at ITPdiesel.com. He can help you.
 
#4 ·
Aeromotive 11108 Marine feed my BD's! Give me a call I can tell you about my setup if you interested.
 

Attachments

#5 ·
Are there any advantages to running two stock pumps in parallel?

Dual fuel pickups into stock pumps into single bank of cylinder heads into single regulator into single return.

Logic goes like this:

If the stock pump is good to 70+psi for stock injectors, then I think it would take a whole lotta fuel (at least double) to drop pressure when feeding half the cylinders.

Of course, I have no idea what your injectors flow and since I'm not looking at big squirt sticks then :shrug:

prt
 
#6 ·
my thoughts exactly

plainredtruck said:
Are there any advantages to running two stock pumps in parallel?

Dual fuel pickups into stock pumps into single bank of cylinder heads into single regulator into single return.

Logic goes like this:

If the stock pump is good to 70+psi for stock injectors, then I think it would take a whole lotta fuel (at least double) to drop pressure when feeding half the cylinders.

Of course, I have no idea what your injectors flow and since I'm not looking at big squirt sticks then :shrug:

prt

Thats what I was thinking. Theoretically with 2 pumps you should be able to supply 2X the fuel volume at the same pressure. Give us a detaied description of how your fuel system is routed with line/fitting sizes. I would bet the problem lies there.

I am not wanting to talk you out of a new pump or a lift pump, I think they are great - just a little pricey.
I was trying to
figure out the best way to solve this
 
#7 ·
First off, don't pay any attention to my sig. as it no longer applies, I've just got home and haven't updated. :poke:


The fuel systems that BTS has used and is useing on thier trucks are done like this:

In tank filter mod.
External filter
Replace the steel lines to a new SD fuel pump
Plumb the new pump directly into the existing pump
Wire them together


The new pump and the old pump are using the same size fuel line as stock, just doubling the preasure
This setup has worked well for them in the past, just won 't seem to work on mine. We bypassed the external filter thinking that was the problem but it did not help.
We really needed to get home and couldn't fool with it any longer at thier shop.

I'm now running 530's and the fuel preasure will drop from 70psi to 20psi at WOT. ( this is observed on the dyno, watching the fuel preasure gauge under the hood)


Thanks for all the help and info, Keep it coming!!
 
#8 ·
Ok first off you are probably using way too much fuel be using the stock fuel lines and regualtor system. I am not speaking from experience but just a good possibility.
The other thing that comes to mind is the check valves and screens in the fuel inlet fittings. If one or both of these is plugged it would not allow enough fuel to pass through at WOT.

If I were to run 2 pumps I would not run them in series as you explained. They will probably produce more pressure that way but what you are needing is VOLUME and it will only increase slightly. If you have 2 lines feeding them (5/16 min.) and 2 lines from the pumps to the heads you will be doubling the volume capability as compared to stock. You could also have a 1/2" line from the tank to a filter and come out of the filter head with 2 5/16 lines. Same thing could be done on the pressure side with a final filter - 2 5/16 lines in and 1 1/2" line out to the engine.

I just got done with the fuel system on my OBS. Check out my pics by clicking the link in my sig. And also see my thread in the 7.3 forum - Finaly got some pics. I have part numbers for all the parts I used and these could all be used with a dual pump setup like I am talking about.

Here is an ITP regulated return kit

I would suggest getting something of that sort on there whether a kit or a DIY system. I think Beans has a kit as well.
 
#9 ·
Due to the design of nearly every electric fuel pump made (and many mechanical pumps), if you increase the fuel pressure, you DECRESE the pump's FLOW CAPACITY. Fuel pumps are rated in GPH, LPH or lb/hr at a given pressure. There is a formula that gives the new flow at the new pressure.

If the pump will flow 255L/hr at 60 PSI, and you increase the pressure to 120 PSI it flows less. The amount less (or more if at lower pressure) goes as: new = rated (flow) times the square root of the pressure at rated (flow) the rated flow divided by actual pressure. Rated pressure is 60 psi ,flow is (assumed) 255l/hr.

Doing the math on it:
New flow => 60/(60+60) = 0.5 (ratio of old to new), we take the Sq Rt of this = 0.707 and multiply by the rated flow (255l/hr) to get 180.28l/hr.

So, we increased pressure, but DECREASED the peak flow capacity of the pump by nearly 30%.

To increase total fuel flow, especially with larger injectors (high power applications) you need a pump RATED for more flow, or more pumps.

If you do the math again, with to pressure pumps in series (one after the other) we find that the pressure is doubled, and the flow remains the same because the pressure drop (change actually) accross each pump is still at or below the rated pressure. 0->60 = 60 psi increase, 60-> 120 = 60 psi increase. What we did not accomplish is to increase the flow capacity of the pump(s), but we did increase the flow capacity of the supply system somewhat.

The REAL trick is to keep the stock pressure but increase flow capacity with the power levels. To give an example, let's say the stock power is 250 WHP, and we now make 500 WHP. We need to FLOW twice as much fuel. Most likely, the stock pump CAN keep up with demand, if the rest of the system can as well. If the stock fuel lines are 3/8" (0.375") ID, the cross-sectional area is pi*r^2 = 3.14 * (0.375/2)^2 = 3.14 * (3/16)^2 = 3.14 * 0.035" = 0.110 sq-in. To maintain flow at twice the power, the line now NEEDS to be 2 * 0.110 sq-in, or 0.220i sq-in.

What ID? 0.220/pi = r^2 = 0.0703. Remember is was r^2, so we need to find the sq-rt ( x-^2), and 0.0703-^2 = r = 0.264", d = 0.528" ~(17/32").

Most turbo-diesels have a BSFC of something close to 0.45. That's how many POUNDS of diesel it takes to make on HP (per hour). To figure out if the pump can support this, more math. 255l/hr =~ 67G/hr. Diesel weighs ~7.2lb/G, so 7.2 * 67 = 482.4 lbs/hr which if we divide bt 0.45 gies us HP/hr = 482.4/0.44 = ~1071 HP/hr.

Fuel supply size is one of the most often overlooked factors in making power.
 
#10 ·
John, I like you and all... But can you speak english??? LOL

I get what your saying but the math is killin me!!! What size fuel line is it? :kissazz:
 
#11 ·
LoL!!!

Sorry man... certain people on the board refuse to believe anything if it contradicts "conventional wisdom", so math is a requirement as "proof".
 
#13 ·
OK, so math is required to prove it works, but if it can be made to work without all the math repeated every stinkin' time somebody wants to put a fuel system on their trucks then we're a step closer to getting a user-friendly DIY/hybrid fuel system. :poke: (that's not meant as a slam John, I just agree with CSIPSD on the whole math thing).

I like ITP's reg return and it's the core of my regulated return fuel system, but I didn't have the $ for a full high flow fuel system so I started collecting parts. I have a FluidAir/Parker store close by so lunchtime every couple of weeks I go hang out and test-fit things. I still spent a nice chunk of change with a couple of vendors on here even when some of the "big ticket" items were available locally.

My thinking (and it's design theory at this time) goes something like this -

1. 5/8" pickup into #6 fuel line into Dahl 100 into stock pump into #6 fuel line to head on one side

2. Repeat for the head on the other side

3. Modify reg return fuel lines as (if) needed and route return through stock fuel bowl (with/without factory filter installed?) into regulator into return line into fuel cooler into tank.

I don't know if this will work with your injectors as they are hungry little fellers. If the flow rate is greater than double the AD's you pulled out it may not work, but if it doesn't exceed factory flow rates at 65-72 psi I think you should have a working fuel system. The only other variable I would consider is whether or not to put a post-pump filter on (that was the with/without factory filter question above) to prevent damage in the event one of the pumps decided to blow chunks through those 'spensive squirt sticks.


I know folks have done similar installs and as far as I know there's not a vendor out there who sells a system just like this; but it just seems like a decent logical answer when the parts end up costing about the same as one of the high-flow fuel delivery systems available.

Just a thought.


prt
 
#14 ·
Diesel Dog said:
Whats getting me though is that this same system is working well on other high HP trucks with the same type of injectors. :shrug:
I really think you need to examine every hose, connection, and possible restriction point especially the check valves/screens in the fittings in the heads - I am pretty sure the SD's have those also. You could have a hose pinched partially shut somewhere.

John - thanks for the great mathmatical explanation. That is the same thing I was trying to get across.
 
#15 ·
Diesel Dog said:
Whats getting me though is that this same system is working well on other high HP trucks with the same type of injectors. :shrug:
How many trucks have they tried this setup on? Most of the truck I know have some form of a regulated return setup w/ larger lines and SX or Aeromotive type pumps.

Dave
 
#16 ·
D2HP said:
How many trucks have they tried this setup on? Most of the truck I know have some form of a regulated return setup w/ larger lines and SX or Aeromotive type pumps.

Dave

They have it on 3 or 4 that we talked about. Patty's truck is running 530's with bigger nozzels than I am and they don't have any issues with it. Greg (Dockboy) is useing this same setup also with no issues.
 
#17 ·
Anyting bigger than 0.25" (-4 Aeroquip) to the HEADS is utterly pointless, unless you are adding even more bends then the factory did :poke:
 
#18 ·
I know hooked to the sled I have no drop in pressure, but my system is way overkill.
 
#19 ·
Let me throw this out as I just thought of it.

If we don't have the regulator for the MAP sensor set right could it be defueling at WOT and only allowing 20psi ?

I haven't felt the defuel on the road or even noticed it while driving but you sure can watch it while on the dyno.
 
#20 ·
I really don't think the defueling is going to affect fuel pressure. I would guess that it would just pull back the amount of fuel that the computer is telling the injector to let out. More or less the same as backing off the pedal.

I agree with John 1/4" line is the absolute max necessary for feed to each head unless of course you have the heads off of the truck and drill out the 1/8" pipe thread feed ports and tap them for 1/4" pipe thread.
 
#21 ·
I run 2 superduty pumps in series, with an aeromotive regulator, stock selector valve, with no tank mods. I run 3/8" hose from the selector valve up to a T which splits into 2- 3/8 hoses taht feed each head, then i just feed the heads with the 1/8" pipe fittings on the back. 63psi on a long wot pass with 238cc hybrids. Havent got around to checking fp with the 275cc bd's yet.
 
#22 ·
I ran a FASS 150/150 with a modified pump motor as a stand alone pump.
-8 from the bottom of the tank to the pump....-6 to the stock secondary fuel filter housing...-4 to the heads.
Stock regulator is gutted but I use the stock return line through an SX adjustable regulator.
Idle PSI is about 52...ramps up to 70ish at WOT.

We did virtually the same system on David Lott's red truck....except it doesn't use a boost feed. It maintains 60 PSI or so at any throttle position.
 
#23 ·
I went with MagnaFuel stuff......... probably overkill.

-12 from the tank to pump, -10 to the fuel log, and -8 to the heads. Like I said, more than enough.LOL



Here's a shot of the fuel log without the n2o solenoids hiding everything. Sweet regulator.


And the good stuff:


:sly:
 
#24 ·
Diesel Dog said:
Greg (Dockboy) is useing this same setup also with no issues.
If you mean the twin stock pumps, no he isn't. Greg was running a single SX pump (if I'm not mistaken) until it took a crap on the way to the last "Smokin' in the Smokies" event. Since then he's had the Aeromotive A1000 out of Jodys truck (until he damaged the engine recently at the track). The A1000 is on the way back to Jody and when the truck comes back to life it will have my new pump setup installed.
 
#25 ·
racehauler said:
I agree with John 1/4" line is the absolute max necessary for feed to each head unless of course you have the heads off of the truck and drill out the 1/8" pipe thread feed ports and tap them for 1/4" pipe thread.

There is not enough meat in the head to drill the 1/8 inch holes out to 1/4. If you wont the better route, you run the fuel lines from the dual pumps to the end of the fuel rail in the back of the head where it is drilled all the way through the head. Now you have a much larger opening and no drilling required. Just plug the 1/8 inch holes and forget about them as feed holes. You can run your regulated return off of the front 1/8 inch holes and your done.

FOMOGO
 
#26 ·
ITPDiesel said:
If you mean the twin stock pumps, no he isn't. Greg was running a single SX pump (if I'm not mistaken) until it took a crap on the way to the last "Smokin' in the Smokies" event. Since then he's had the Aeromotive A1000 out of Jodys truck (until he damaged the engine recently at the track). The A1000 is on the way back to Jody and when the truck comes back to life it will have my new pump setup installed.

I was under the impression he was running the twin SD pumps, sorry about that!

Dennis, I sent you a PM about the new pump, not looking for a beta tester are you? :sly:

I promise to give it a good work out :poke:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top