Let's talk: high HP fuel systems

[BrokenTsi]

My current setup is a bosch 044 in tank with -8an to a -8an fuel filter, and then to the stock fuel rail, and an aeromotive afpr with a stock return line.

I have not maxxed out this setup, I'm not sure what its capable of, but I know I want to re-do my fuel system in a few months for next season.

I want to sump the stock tank with 2 -8AN fittings to feed dual bosch 044's to each side of the fuel rail. Then return from the center of the rail to the FPR.

For those who are running external pumps, where did you mount them (1g)?

For those who have made a sump, what are the dimensions?

I would like to wire these straight to the battery with a fuse and switch. Is a relay really necessary?

How do you wire them so that if one pump fails, it shuts off the other pump?

I'm open to all suggestions.

 

[mike96]

I want to sump the stock tank with 2 -8AN fittings to feed dual bosch 044's to each side of the fuel rail. Then return from the center of the rail to the FPR.

is that even possible??? i understand what you are trying to accomplish in doing it this way by maximizing the amount of fuel flowing to the injectors by cutting your fuel circuit in 2. but... unless 1G rails are different than 2G rails (which i don’t think they are) there are only 3 bolts holding the fuel rail to the head which would mean you would lose one by cutting the rail to add in a pair of AN fittings. unless you are going to fab something else to help hold the rail down that seems kind of un safe. don’t forget you will defiantly need to upgrade the return line, i highly doubt the stock one will keep up with that much fuel.

I would like to wire these straight to the battery with a fuse and switch. Is a relay really necessary?

i don’t think you would really want it done any other way. if i am not mistaken the factory ecu turns the stock relay off when the engine isn’t running just in case something happens. you don’t want your fuel pumps to continue to run if a fuel line ruptures and your engine dies due to lack of fuel... that would be really bad if you hit the wall...

How do you wire them so that if one pump fails, it shuts off the other pump?

pressure switch??? that way if the one pump quits it will shut off power to the other one, may be? i will have to think about that one for a minute.

 

[ramsack]

There are 3 bolts holding all 4g63 rails to the head, and he doesn't have to cut the rail in 2. He could just drill a hole and have a bung welded onto the rail in the middle of it for return. This is a good idea. Each feed only having to supply 2 injectors in theory, makes it so you don't have to get a HUGE rail and have a pressure loss at the last injector. A pressure switch would only work to shut one pump off if you are maxxing out a single pump. It would then be too late. There are most likely circuits out there that can sense current usage and shut off one of the pumps.

 

[BrokenTsi]

Think about it like this. Are your fuel pumps on when the key is on but the engine is off? I would think its the same thing as having a switch. Turn the key on, arm the switch. What about when you turn on your fuel pump thru Ecmlink? Engine still isnt running, but the lines get pressurized. Unless I'm mistaken.

I would of course upgrade my return line, but I dont think its necessary honestly.

I can either weld a bung onto the back of a stock fuel rail, or just get an AEM rail that already has it on there. It would still be the same amount of fuel pressure regardless of how many pumps I have. Again, correct me if I'm wrong.

I suppose I could run 2 pumps in line with a Y block for the fuel rail. I just don't want to use intank pumps anymore. I think I would benefit with a fuel sump on the stock gas tank. When I have 1/4 tank of gas, it actually cuts out under acceleration sometimes. When I go to the track, I just bring a 5 gallon drum/can of race gas with me on a near empty tank.

I also want a failsafe for the fuel pumps in case something happens. Its easy when my only pump dies. The car stops running, .

 

[ramsack]

The AEM rail is smaller than stock in case you didn't realize. And the port you are talking about is right on the normal return end. It is only 1/8" NPT. Likely to create too much of a pressure difference between the regulator and the rail itself, so the rail would be a higher pressure.

 

[BrokenTsi]

The AEM rail is smaller than stock in case you didn't realize. And the port you are talking about is right on the normal return end. It is only 1/8" NPT. Likely to create too much of a pressure difference between the regulator and the rail itself, so the rail would be a higher pressure.

Alright, then another fuel rail with better options will work. I just kinda threw AEM out there off the top of my head, but if it doesnt work, it doesnt work.

I know someone makes a fuel rail that will accomodate a -8an feed and at least a -6an return.

 

[DGajre777]

Alright, then another fuel rail with better options will work. I just kinda threw AEM out there off the top of my head, but if it doesnt work, it doesnt work.

I know someone makes a fuel rail that will accomodate a -8an feed and at least a -6an return.

A stock 1G rail is a little bit "open" compared to a 2G rail which is tapered towards the middle. If you compare the two, the 1G is " || " while the 2G is a little bit like this " )( "

Here's a fuel rail where you can use an -8an on one side and a -6an on the other side. Fuel Rail by Race Components Inc.

 

[mike96]

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Think about it like this. Are your fuel pumps on when the key is on but the engine is off? I would think its the same thing as having a switch. Turn the key on, arm the switch. What about when you turn on your fuel pump thru Ecmlink? Engine still isnt running, but the lines get pressurized. Unless I'm mistaken.

the way i understand it is that the fuel pump doesn't turn on until you actually start cranking the engine, if the engine stops running for any reason and the ECU stops receiving a cam/crank signal the pump quits running. reason is if something happens like i mentioned earlier you don't end up with a engine bay full of fuel and then accidentally try cranking the engine over and start a fire.

I would of course upgrade my return line, but I don't think its necessary honestly.

interesting thing is every other car i have ever worked on the return line was bigger than the pressure line. the size of the return on a DSM its tiny. i don't think there is any way it would return the amount of fuel the duel 044's would pump out. just my opinion anyway.

I can either weld a bung onto the back of a stock fuel rail, or just get an AEM rail that already has it on there. It would still be the same amount of fuel pressure regardless of how many pumps I have. Again, correct me if I'm wrong.

yea welding a bung to the middle of the rail would do the trick. it would basically be the same as what the Subaru guys do to their cars being that they have 2 fuel rails the factory runs them in series, they re-plumb them to run in parallel. your setup would basically be the same only you would have the two pumps. yes fuel pressure would be the same only you would have twice the flow of fuel.

I suppose I could run 2 pumps in line with a Y block for the fuel rail. I just don't want to use in tank pumps anymore. I think I would benefit with a fuel sump on the stock gas tank. When I have 1/4 tank of gas, it actually cuts out under acceleration sometimes. When I go to the track, I just bring a 5 gallon drum/can of race gas with me on a near empty tank.

definitely sounds like you could use a sump or maybe bet rid of the factory plastic baffle and shove a bunch of racing foam in the tank that might help with the starvation.

I also want a failsafe for the fuel pumps in case something happens. Its easy when my only pump dies. The car stops running, .

basically here is what i was talking about with the pressure switches as a fail safe. if you look at the crappy diagram i drew you see the way it is wired if "pump a" stops working the switch on that fuel line would shut off power to "pump b" and if "pump b" shuts down then "pump a" loses power.you would need a check valve in line to keep one pump from accidentally pressurizing the switch and keeping power running when there is a failure, but i think you have the idea. only problem you would have is that you would need a way to run power to the pump to get the fuel lines pressurized to start with. like maybe a relay that is active only then the starter is running, then once the car starts the switches would run power to the pumps and keeps the car running.


my pic isnt working...

 

[BrokenTsi]

Thanks for the info. It seems like there are easy provisions for the fuel rail in this setup. So thats taken care of.

Oh, BTW, 1g's have steel tanks. So welding on a fuel sump is easy. Don't 2g's have plastic tanks?

I have a basic re-wire on my bosch 044 with a relay, and the relay gets power straight from my battery. I suppose for dual pumps, I would upgrade that relay and wire them together?

Let's talk fuel pumps. Maybe this setup is overkill. If I ran an inline feeding another inline and wired them to ONE relay maybe that will do the trick. Keeping cost down would be nice, so how about two in-line walbro's? 2 bosch 044's arent out of the question tho. Is there an affordable single pump that will handle the fuel pressure I would need?

 

[habitatguy187]

Let's talk fuel pumps. Maybe this setup is overkill. If I ran an inline feeding another inline and wired them to ONE relay maybe that will do the trick. Keeping cost down would be nice, so how about two in-line walbro's? 2 bosch 044's arent out of the question tho. Is there an affordable single pump that will handle the fuel pressure I would need?

I wrote out a long post for this thread yesterday questioning the overkill of this setup, but when I hit "submit" tuners went down and it didn't save anything


So anyway, you could get a eliminator fuel pump, or you could just get another bosch and put it inline with the one you already have. That would be more than enough fuel and it'd be cheaper.

However; if you can do the dual-feed setup for a reasonable price I would do it if I were you, I always hated this article from vfaq concerning fuel pressure drop off. - http://www.stevetek.com/R-FuelSys.html

 

[TSimage]

I too wrote out a rant that didn't get submitted. Basically questioning why you are attempting to reinvent the wheel. Kind of like the blind leading the blind. I definitely got a chuckle out of reading ramscaks reply.



This is a pressurized liquid system, you need not worry about anything "tapering" off towards the final injector, this just doesn't happened on a properly setup system. These aren't intake manifolds and weir not talking about gas volume in a large plenum... And rest assured that the Magnum and AEM rails are upgrades and make it very simple to run -10an lines.

For your setup you can run it 2 ways.

1) 2 -8an fuel lines from tank to 2 prefilters and then into your 2 boschs. Y the boschs into a -10an line and run that to your final filter and then go directly into ONE SIDE of the fking rail. I'd recommend a -8an return into your AFPR and then back to your tank.

Or my setup:

2) 1 -10/12an line into one prefilter, Y'd into -8ans directly tot he 2 pumps which are then Y'd back into a -10 (the rest of the system runs as described above)

I'm not sure what you plan on accomplishing or gaining with the odd way you are wanting to run it but do yourself a favor and don't. Many have made much more power than what you are planning to with even less. The dual Bosch setup I mentioned is good for 1000hp all day long. Just use what works and go with it. You wont be doing anything worth hacking everything up as you described. Most likely you would be just fine adding an in tank Walbro to your fuel setup before your Bosch and calling it a day.

 

[BrokenTsi]

I too wrote out a rant that didn't get submitted. Basically questioning why you are attempting to reinvent the wheel. Kind of like the blind leading the blind. I definitely got a chuckle out of reading ramscaks reply.



This is a pressurized liquid system, you need not worry about anything "tapering" off towards the final injector, this just doesn't happened on a properly setup system. These aren't intake manifolds and weir not talking about gas volume in a large plenum... And rest assured that the Magnum and AEM rails are upgrades and make it very simple to run -10an lines.

For your setup you can run it 2 ways.

1) 2 -8an fuel lines from tank to 2 prefilters and then into your 2 boschs. Y the boschs into a -10an line and run that to your final filter and then go directly into ONE SIDE of the fking rail. I'd recommend a -8an return into your AFPR and then back to your tank.

Or my setup:

2) 1 -10/12an line into one prefilter, Y'd into -8ans directly tot he 2 pumps which are then Y'd back into a -10 (the rest of the system runs as described above)

I'm not sure what you plan on accomplishing or gaining with the odd way you are wanting to run it but do yourself a favor and don't. Many have made much more power than what you are planning to with even less. The dual Bosch setup I mentioned is good for 1000hp all day long. Just use what works and go with it. You wont be doing anything worth hacking everything up as you described. Most likely you would be just fine adding an in tank Walbro to your fuel setup before your Bosch and calling it a day.

I'm liking the way you run your fuel system. I know I could just toss another bosch 044 inline and call it a day, but I really don't want to use the stock sending unit at all. I would much rather weld on a sump to the stock tank. Thanks for your input.

Can you give me a brief layout of how you have it wired?

 

[TSimage]

I'm liking the way you run your fuel system. I know I could just toss another bosch 044 inline and call it a day, but I really don't want to use the stock sending unit at all. I would much rather weld on a sump to the stock tank. Thanks for your input.

Can you give me a brief layout of how you have it wired?

They are wired together into one large relay that way if something happens to the relay, they both shut off. Problem is I assume that if one pump died on me that the other would keep running but I'm not worried about that in all honesty. Both pumps are new with only testing time on them and I keep a heavy eye on my WideBand at all times (almost too much)

 

[ceedawg]

Many have made much more power than what you are planning to with even less. The dual Bosch setup I mentioned is good for 1000hp all day long. Just use what works and go with it. You wont be doing anything worth hacking everything up as you described. Most likely you would be just fine adding an in tank Walbro to your fuel setup before your Bosch and calling it a day.

I guess this was the answer I was looking for. I'm only trying to make at least 500whp+ on pump 93 and was wondering if my present setup which is a -8 setup from the fuel rail to the tank,stck return, with 950 cc inj and wired walbro255 pump setup was efficient enuff. I am hoping not to have to goto a dual fuel pump setup.

 

[2gGSX]

I guess this was the answer I was looking for. I'm only trying to make at least 500whp+ on pump 93 and was wondering if my present setup which is a -8 setup from the fuel rail to the tank,stck return, with 950 cc inj and wired walbro255 pump setup was efficient enuff. I am hoping not to have to goto a dual fuel pump setup.

That should be more than enough.

 

[Slippi84]

I too wrote out a rant that didn't get submitted. Basically questioning why you are attempting to reinvent the wheel. Kind of like the blind leading the blind. I definitely got a chuckle out of reading ramscaks reply.



This is a pressurized liquid system, you need not worry about anything "tapering" off towards the final injector, this just doesn't happened on a properly setup system. These aren't intake manifolds and weir not talking about gas volume in a large plenum... And rest assured that the Magnum and AEM rails are upgrades and make it very simple to run -10an lines.

For your setup you can run it 2 ways.

1) 2 -8an fuel lines from tank to 2 prefilters and then into your 2 boschs. Y the boschs into a -10an line and run that to your final filter and then go directly into ONE SIDE of the fking rail. I'd recommend a -8an return into your AFPR and then back to your tank.

Or my setup:

2) 1 -10/12an line into one prefilter, Y'd into -8ans directly tot he 2 pumps which are then Y'd back into a -10 (the rest of the system runs as described above)

I'm not sure what you plan on accomplishing or gaining with the odd way you are wanting to run it but do yourself a favor and don't. Many have made much more power than what you are planning to with even less. The dual Bosch setup I mentioned is good for 1000hp all day long. Just use what works and go with it. You wont be doing anything worth hacking everything up as you described. Most likely you would be just fine adding an in tank Walbro to your fuel setup before your Bosch and calling it a day.

Not true Tim ZImmer maxed it out at about 780whp with a s400sx.

 

[diambo4life]

I would definitely add another 044 or Walbro 392 and set it up in a parallel configuration. That would be overkill and good for a decent amount of power especially on gasoline.

FWIW, my external pump is mounted on the firewall.

 

[spoolin ddub]

I had a inline 044 and a supra pump intank. Decided to run intank 044 to inline 044. But If you are going to redo everything keep it simple. Sump your tank stay with 8an lines and just go single like a magnafuel pump.

 

[slowgsr]

I use full blowns twin parallel 255lph walbro's. -8 feed, -6 return though a fuel lab filter, the rail is a FIC unit and the injectors are FIC 2150s. I run gas and these injectors idle awesome. Stock tank, I want to switch out to the JM fab 1g stock location fuel cell though.

Keep it simple, my setup is good for a ton of power. For wiring.. I ran a 8ga wire from the battery fused at 40amps, and I use a heavy duty automotive relay (40amp) and its switched by the factory signal wire.

The twin walbro setup in the stock tank on a hanger, is just so friggen easy. I just can't run 80psi of base pressure with the pumps, but the combination of dual walbro's in parallel and my 2150s I don't need to, it will still support.. enough... ha.

 

[Slippi84]

I have one external Magnafuel pump with -10an feed and -an return with two inlines filters and a jmf fuel cell and I may need more injector but I will never need a bigger pump or lines unless I want to chase brent

 

[BrokenTsi]

Right. But you kinda skipped all the inbetween fuel setups since you havent really had the chance to test out anything yet. So for some, your setup just may be way too overkill. Most of us have been adding on to the stock fuel system.

I bet I'll run 9's on the stock gas tank with the bosch 044 in the tank.

 

[TSimage]

Not true Tim ZImmer maxed it out at about 780whp with a s400sx.

Oddly enough I have seen people make more power than Tim using the same setup and less...


There are lots of variables in every system but that is on the low side power-wise unless you are referring to an auto. And in an Auto 780 is good for 8s so its all good either way.

On a side note.

780whp = roughly 1000hp, once again proving my point however we wont bicker over trivial numbers. I wanna do 8s/9s and dual Bosch are the setup of choice on many platforms including our own to achieve my goals. I'll be just fine, I'm 100% sure of it. Push come to shove I still have my Mag and Aero pumps.