How to: Survyor2's 750+rwhp dual pump 1/2" fuel system

[survyor2]

As requested, I did a write up on my new -8 (1/2 inch) fuel setup using a Bosch 044 fuel pump and a Walbro 255 fuel pump. I plan to use this to get me to 600rwhp. If you followed my other thread, I hit 540ft-lb torque then ran out of fuel when I got to 5000 rpm. Here is everything you need.

Front to back:

Stock fuel rail
copper washer (back of fuel rail)
-8an to 14mm x 1.5 male/male (back of fuel rail)
-8an 90degree female/hose end (back of fuel rail) (note: you can use a 180degree fitting here if desired)
-8an SS line 8.3 feet (fuel rail to fuel filter)
-8an hose end/female (fuel filter)
-8an to 3/8" male/male (fuel filter)
Mallory Ignition 3160 fuel injection filter (3/8"plug x2 to plug input #2 and output #2)
-8an to 3/8" male/male (fuel filter)
-8an 45degree hose end/female (fuel filter)
-8an SS line 2.5 feet (fuel filter to bosch fp)
-8an hose end/female (bosch fp outlet)
-8an to 12mm x 1.5 male/male (bosch fp outlet)
copper washer
Bosch 044 300lph fuel pump
copper washer
-8an to 18mm x 1.5 male/male (bosch fp inlet)
-8an hose end/female (bosch fp inlet)
-8an SS line 2.4 feet (bosch fp to fuel tank)
-8an hose end/female (outside fuel tank)
-8an 90 degree bulkhead union male/male (taps into fuel tank)
copper washer (outside fuel tank)
copper washer (inside fuel tank)
-8an bulkhead nut (taps into fuel tank)
-8an 45degree female/female (bulkhead to walbro fp)
-8an to -6an male/male (bulkhead to walbro fp)
-6an 45degree to -6 barb female/barb (bulkhead to walbro fp)
-6an intank fuel line w/ 2 clamps (bulkhead to walbro fp)
Walbro 255lph fuel pump

I needed 15 feet of the -8an SS hose and only need a few inches of the -6an hose. Brackets for the hose length (Summit racing SUM-G1883) are needed paired with self tapping screws. Bulldog #10x3/4" 6 pack from Walmart worked great. I also ordered Summit Racing fuel pump relay kit (SUM-890023).


I started at the fuel rail using a copper washer, 14mm fitting and 45 degree fitting:

The high speed grinder tool cuts the braided line without fraying it much. Be sure to clean the inside of the tube out. The rubber dusts gets in there:

Hose ends onto braided line:

Installed on fuel rail:

Secure hose brackets along bottom of body:

Mallory filter with 3/8" fittings and hose ends. Outlet is a straight hose end and the inlet is a 45degree hose end to clear the subframe. Because their are 2 inlets and 2 outlets, 3/8" plugs are needed for 1 inlet and 1 outlet.

Bosch 044 fuel pump with copper washers and 18mm and 12mm fittings:

I used a 2.5 inch silicon coupler as insulation:

Braided hose from fuel filter to fuel pump with straight and 45degree hose ends:

Fuel pump with straps and 2 self tapping screws. I used 2 existing bolts to hold down the other end of the straps:

 

[survyor2]

Braided hose from fuel pump to top of fuel tank. 2.5 feet in length with 2 straight hose ends:

The final and most complicated piece is the fuel tank hanger. I removed the hanger with my Walbro 255 installed:

Fuel pump removed:

Use cutting tool to remove the stock outlet hard line. Most of the lines just break off when you cut the welded clamp:

Drill out the stock outlet to the size of the bulkhead fitting. Install the bulkhead fitting with 2 copper washers. One washer inside and one washer outside. The bulkhead nut goes on the inside. The nut is so close to the hanger that you must turn the bulkhead fitting on the outside to tighten. Next is the 45degree bend. A straight fitting will hit the hanger. A -8 male to -6 male fitting is next and then a -6 45degree barb. Next is the -6 fuel line from the barb to the Walbro with 2 new clamps. Once all the fittings are finalized, I used red loctite on the bulkhead nut

Torque everything down. When I reinstalled the Walbro fuel pump hanger, the bulkhead nut hit the side of the fuel tank. I had to notch out some of the metal. I had to fill the tank with water to remove the gas vapors and then dremel a notch. It took 2 days for the tank to dry out after I emptied the water. I had to trim the gasket also.

I already have an aftermarket fuel pressure regulater installed. This would be a requirement. Basicly I have a -6 90degree fitting on the front of the fuel rail 12mmx1.5 going to a -6 45degree fitting via a -6 braided hose. This goes to my AFPR. The oulet is a straight -6 braided line clamped to the stock return line. You would need at least 680cc injectors to make use of this much fuel.



---------- Post added at 08:40 AM ---------- Previous post was at 08:38 AM ----------



Wiring:

Summit fuel pump relay kit (SUM-890023). 30 amps should be enough to support both pumps. The bosch 044 draws a maximum of 15 amps and the walbro 255 draws a maximum of 12 amps. Not to mention that someone on the ls1 forums is running two bosch 044s off of one 30 amp fuse and has never blow a fuse or had any issues.

Relay wiring: Red wiring from battery to 30amp circuit breaker to relay. Grey wire is grounded. Purple wire from relay to Bosch fuel pump.

Bosch 044 fuel pump wiring: Purple wire from realy to Bosch fuel pump then Bosch fuel pump to fuel pump wiring harness for Walbro fuel pump. Black wire from Bosch ground post to ground.

Walbro fuel pump wiring. Purple wire from positive post on Bosch fuel pump to black wire on chasis harness side of gray plug. Yes, black is the power wire. Now, run the yellow wire from the relay to the other end of the black wire on the chasis harness side of the gray plug. The yellow wire is now sourced from the stock fuel pump relay.

Install tank and plug in the gray plug (fuel pump) and the white plug (fuel level sender). Install access door in trunk.



---------- Post added at 08:41 AM ---------- Previous post was at 08:40 AM ----------



Why go bosch + walbro inline instead of Aeromotive A1000 or dual parallel?

The bosch and walbro fuel pump won't fit in the tank.

Think of each pump having a low pressure side (inlet) and a high pressure side (outlet). The low pressure side of the in-tank pump is at about zero psi, the high pressure side will only be at a few psi since the Bosch 044 pump is not providing any real restriction. Then, the Bosch 044 pump with the inlet, at a few psi, can push more fuel at higher pressures than it would be able to otherwise. Basically, the "boost" from the in-tank pump shifts the Bosch fuel pump's entire output curve up, especially critical at the higher pressures.

"Basically a positive displacement fuel pump creates flow and the fuel pressure regulator causes a "restriction" after the fuel injectors to create pressure. Fuel flow (volume per time) is independant of fuel pressure (force per area).

The in-tank pump is creating low pressure and high volume. Then the Bosch 044 pump would create higher pressure and have to work less to make higher volume. This gives the Bosch 044 pump the capability to create higher flow than it normally would.

Imagine a single intank pump setup. Imagine you've found a way to pressurize the gas tank. This increase in static pressure would push the fuel into (and through) the in-tank fuel pump easier, meaning the in-tank pump would not need to work as hard to create the pressure required by the fuel pressure regulator (it would draw less current that it did before you pressurized the tank). This would give that same pump the ability to create more flow at higher pressures when the output would typically fall off. See this graph to illustrate how a pumps output decreases as pressure increases and how the required current (how hard the pump is working) increases as pressure increases.

Source: http://www.jayracing.com

i also wanted to post this graph for people thinking of going A1000 external. Yes it will flow more at low boost but when I start getting up to 30psi of boost (40 base + 30 = 70 psi fuel pressure), things change. Note that this is for single fuel pumps. I'd love to have a bosch + walbro flow chart.

And mostly important, I went with this setup because its PROVEN many times to work. And is highly recommended by people I trust on and off the internet.

Dennis

 

[IJ.]

A few questions, How did you come up with the 750+rwhp figure?

Are you running any sort of Fuel Temp compensation to cope with the density change once it's heat soaked the contents of the tank?

Are you going to replace those ugly horrible straps on the Pump?
(Aeromotive make some really sweet T Bolt clamps for the Tsunami pumps that might work with the silicone wrapped Bosch)

 

[survyor2]

The specs on the bosch 044 are 685hp alone. The specs on the walbro 255 are 640 hp. I've read lots of forums to find out the maximum horsepower capibilities of the walbro with the inline bosch fuel pump. Some claims were conservative, some were more than 750. Check out the "DG Motors 750 hp fuel system" available for Evos. That kit includes the in-tank walbro 255 and bosch 044 fuel pumps along with 1000cc injectors. My -8an line would even flow more than that kit's -6an lines. My point is its advertised as a "750hp kit".

No type of fuel temp compensation. In all my research and looking at many other setups this issue never came up with people with bosch and walbro setups.

Straps are ugly, yes. But I don't care, I can't see them.

 

[Sinistr]

Looks like a pretty nice setup, but do you suppose that the results would be the same with a Denso+Bosch, as opposed to the Walbro+Bosch?

 

[IJ.]

The specs on the bosch 044 are 685hp alone. The specs on the walbro 255 are 640 hp. I've read lots of forums to find out the maximum horsepower capibilities of the walbro with the inline bosch fuel pump. Some claims were conservative, some were more than 750. Check out the "DG Motors 750 hp fuel system" available for Evos. That kit includes the in-tank walbro 255 and bosch 044 fuel pumps along with 1000cc injectors. My -8an line would even flow more than that kit's -6an lines. My point is its advertised as a "750hp kit".

No type of fuel temp compensation. In all my research and looking at many other setups this issue never came up with people with bosch and walbro setups.

Straps are ugly, yes. But I don't care, I can't see them.

Settle down Dennis they were just questions....

Was just curious if you'd found a formula that took the higher than ambient inlet pressures for the 044 into account and it had spat out 750rwhp....

At low injector duty cycle you still have xxLPM fuel flow, if it can't go into the injectors it goes down the return to the tank after picking up heat in the fuel rail and engine bay, I found after a 2 hour drive my AFR's would drift due to the tank heating up, I designed my fuel system around this issue to minimise the effect but a LOT of OEM cars run a fuel temp sensor in the rail and have a compensation table set up to make allowances for it.

I was just asking as I know it's an issue and was again curious.

Pump straps, personal choice if you're happy with them cool, I was going to offer a couple of the Tsunami brackets I have left over here after selling my dual Tsunami's and replacing then with Mk4TT Denso's but it seem's I've managed to somehow rub sand in your vag so forget it...

 

[becauseican]

Is fuel heating a common problem with the Bosch's in general or just the Booster pump style fuel system?. I just know from experiance that a friend of mine that had the Denso intank and the Bosch 044 inline that after about 30 min on the dyno the fuel was heated up and the fuel tank itself was hot and it made for difficult tuning !!. I feel that an inline fuel cooler similar to the one B&M sells to be a good idea, just not sure if it would be best on the inlet line or after the rail in the return line? I will be installing my inline 044 in the next week here.

IJ, would the AFRs lean out when it heated up?

 

[IJ.]

Randy: If it were just leaning out that would have been fairly easy to tune around but for me it was drifting all over the place to the point I suspected a dying or fouled 02 sensor

I put this down to 2 factors at play, 1 was the heat (after 2 hours driving tanks was very warm to touch) and then an inconsistent rise in Tank pressure as I still use the factory charcoal canister/vapour return system with the big fuel tank.

What I've come up with is parallel Pumps/Lines and run a check valve/non return in each line, I have the ECU set to run both pumps while cranking then switch to one at 50% speed for idle/cruise, only time pump to kicks in is on boost then it ramps in at the same rate as pump #1 coming up from 50% duty to 100% following boost so there's no rich spike. (I'm using the fuel temp channel in the ECU for something else as I've run out of inputs and fuel temp compensation adds another layer of complexity to the tune)

Doing it this way means the return line barely flows anything at idle/cruise and once on boost the bulk of flow goes to the injectors, I like the idea of a cooler but am freaked out at the idea of having fuel out in the airflow in case of accident.

Might be worth testing the 044 to see if the Walbro can push through it while it's off??
(pretty sure it's a gerotor pump so might work)

You could then shut it down when it's not needed and cruise on just the walbro.

 

[suprasom]

great Info

 

[survyor2]

Hey IJ. Sorry you misread my tone. No attitude here at all. I'm happy to hear all comments and questions. You've helped me many times in the past and I apprepiate that. I'll keep an eye out for the heatsoak. I'll run some of my own tests and observations. Just saying nobody has even mentioned or hinted at this issue from my research. I'll use more smiley faces from now on.

Dennis

 

[IJ.]

Hey IJ. Sorry you misread my tone. No attitude here at all. I'm happy to hear all comments and questions. You've helped me many times in the past and I apprepiate that. I'll keep an eye out for the heatsoak. I'll run some of my own tests and observations. Just saying nobody has even mentioned or hinted at this issue from my research. I'll use more smiley faces from now on.

Dennis

No probs Dennis, probably just me being a crotchety old fuck again :: IJ. ::

The effect is real trust me on this one, guess I notice these things as I'll spend weeks working on my road tune and data log hours and hours to disect each evening, couldn't isolate this issue till I stopped for fuel one day and touched the tank then it all fell into place.

 

[MDCmotorsports]

Can we get this into a stick for "how to"?

Indeed a great write up. Not a fan of how you mounted the Bosch pump, but done well none the less.

 

[IJ.]

I would prefer to wait and see how it behaves in use on the road and on the dyno before making it an article as I believe there will be a few issues and it may need some detail changes.

 

[BlackDevilSupra]

If the intent is to extend fuel pump life, then one could consider installing a heat sink type cooler to cool the fuel returning to the tank - like this Derale Flow Through Heat Sink Cooler. But for overall engine performance and HP, focus more on maximizing the cooling of the charged air, rather than trying to chill the fuel. Furthermore, "heated" fuel contributes to better overall vaporization of the injected mist which is an ideal engineering situation for FI systems, but can contribute to vapor lock. So, I would just ignore any intended modifications to cooling the fuel, and rather direct all focus on cooling the incoming air via more efficient IC or with water / meth inj system.

 

[NashMan]

I would run split lum on your fule lines under your car

but that is just me

 

[NTRA08]

on the stock fuel rail for a 7mgte what is the fpr looking thing in the back. And do I need it if I have done fuel upgrades

 

[TurboStreetCar]

Fuel Pulsation Damper. Its a good idea to keep if possible. If not run full rubber lines (not braided) or run an aftermarket one.

When the injectors close a water hammer effect is inflicted upon everything in the pressure side of the fuel system. Id imagine it would be rough on the pump, injectors and regulator. Not to mention any seals or fittings.

 

[Zazzn]

I'm running daul walbro's side by side T'd in to a -8 feed line. I have a -8 feeding the rail and a -6 leaving the rail going to a stock return line.

My setup is
-8 lines for the feed, dual walbros Y piped, -6 return off the rail with a a1000 returning the fuel though the stock lines.

I've had no issues so far with my setup.

I'm not a fan of running 2 pumps inline to be honest, parallel but not inline. Can you do away with the walbro all together and just use the Bosch?

 

[becauseican]

If the intent is to extend fuel pump life, then one could consider installing a heat sink type cooler to cool the fuel returning to the tank - like this Derale Flow Through Heat Sink Cooler. But for overall engine performance and HP, focus more on maximizing the cooling of the charged air, rather than trying to chill the fuel. Furthermore, "heated" fuel contributes to better overall vaporization of the injected mist which is an ideal engineering situation for FI systems, but can contribute to vapor lock. So, I would just ignore any intended modifications to cooling the fuel, and rather direct all focus on cooling the incoming air via more efficient IC or with water / meth inj system.

Its not that the goal is to cool the fuel for performance reasons, its that the fue gets over heated to the point it changes the tune (AFR's) like IJ pointed out. When we were tuning the car I mentioned before, we had it dialed in, then the AFR's started going all over the place, after we had it tuned perfect. We were unsure why this happend so we shut the car down so it would cool off, then while checking over the car we touched the fuel tank and it was HOT to the touch.

IJ what do you think about putting a stock type Fuel pump resistor on the Bosch pump, so its only running 9V for light load then switches to 12V for boost, this way the pump would still be flowing (and the intank would be able to "push " through it without problem), but it wouldnt be re-circulating all the fuel from the tank though the system over heating it. I am not sure how the Bosch pump would respond to the lower voltage but the Denso pumps can do it.....or one could mount an external type cooler in the area bleow the rear seats and run some ducting to guide air to the cooler...just throwing ideas out there as I will be installing my Bosch pump next week.

 

[IJ.]

Randy: I think/feel you might have to take it down lower than 9v to reduce the flow as having the Walbro as a pusher it changes everything but yes something like that might work, you run standalone though don't you?
(never tried to PWM my Bosch pumps so aren't sure how they respond)