Author Topic: I.F. fuel pump placement (question about distances)  (Read 3386 times)

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Offline Jonny Hotnuts

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I.F. fuel pump placement (question about distances)
« on: May 25, 2008, 11:35:21 PM »
Firstly I am going to speak of hose sizing in ID (and approximated), I can’t remember what AN size they are.


Last year our entire fuel system was located entirely in about 4’ from fuel rail to tank.
This year our cell is located in the front of the car. We have a high pressure FI fuel pump with bypassing regulator.

Last year we used 1/2” ID SS hose from the tank, to the pump, to the regulator and from regulator return to tank. We used a 3/8 (?)ID hose on the high pressure side to the fuel rail.


My question is:

Is it OK to mount the fuel pump and regulator close to the tank in the front of the car and a 10' (or so) high pressure line to the fuel rail.

For some reason I think it is recommended that you mount the regulator as close to the motor as possible. THis would mean that I would have to have a 2 runs of larger diameter hose (unless I change fitting sizes, this means getting rid of about 250$ worth of Aeroquip fittings and buy about 200 worth of smaller fittings to suit the new hose)
But of the flip side 2 runs of the larger hose alone will cost about 200 (as apposed to one run of smaller).

The current motor is 1.5 but want the fuel system able to run the turbo motor (500 hp)

Will running a smaller hose to the front be bad for the motor or should I keep the fuel system in the rear and by proxi retain the weight to the back half????

jonny_hotnuts@hotmail.com

"Sometimes it is impossible to deal with her, but most of the time she is very sweet, and if you caress her properly she will sing beautifully."
*Andres Segovia
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Offline Rex Schimmer

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Re: I.F. fuel pump placement (question about distances)
« Reply #1 on: May 26, 2008, 03:16:32 PM »
Jo9nny,
Put the pump close to the fuel tank, pumps like to make pressure not suck. Make the pump connection to the tank 1/2 inch (-8 SAE) Do not put a filter in the suction line, make sure your tank is clean before you run the pump. Then use -6 (3/8) or -8 for the run from the pump to the fuel rail, this is the line you need to put the fuel filter in, this it high pressure and you want to protect the injectors. Then run the fuel line from the filter to the fuel rail, on the other end of the fuel rail put your pressure regulator, this way the fuel pressure is set after the filter and most important the fuel flows thru the fuel rail to the regulator and back to the tank. If your pressure regulator has two ports then the connection is from the far end of the fuel rail to the regulator and from the regulator back to the tank. If your regulator is a three port I would suggest that you plug one of the thru ports and then plumb same as a two port regulator. You want the fuel to run thru the fuel rail and not have a plug at one end with the fuel coming in the other, you will get an air bubble in the rail and the cylinders on that end will be lean. Do not bring the return fuel into the tank close to the pump inlet port as this can cause aeration of the fuel casuse the pump pressure to be eratic. For your return line I would go with either -6 or -8, another way is to use aluminum tubing and 37 1/2 degree AN flares. Pretty easy to bend, makes a nice looking installation, and reduces the amount of SST hose ($)you need.

Putting the fuel cell in the front helps keep the C of G forward which is good for stability.


Rex
Rex

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Offline Sumner

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Re: I.F. fuel pump placement (question about distances)
« Reply #2 on: May 26, 2008, 04:10:21 PM »
Jo9nny,
Put the pump close to the fuel tank, pumps like to make pressure not suck. Make the pump connection to the tank 1/2 inch (-8 SAE) Do not put a filter in the suction line, make sure your tank is clean before you run the pump. Then use -6 (3/8) or -8 for the run from the pump to the fuel rail, this is the line you need to put the fuel filter in, this it high pressure and you want to protect the injectors. Then run the fuel line from the filter to the fuel rail, on the other end of the fuel rail put your pressure regulator, this way the fuel pressure is set after the filter and most important the fuel flows thru the fuel rail to the regulator and back to the tank. If your pressure regulator has two ports then the connection is from the far end of the fuel rail to the regulator and from the regulator back to the tank. If your regulator is a three port I would suggest that you plug one of the thru ports and then plumb same as a two port regulator. You want the fuel to run thru the fuel rail and not have a plug at one end with the fuel coming in the other, you will get an air bubble in the rail and the cylinders on that end will be lean. Do not bring the return fuel into the tank close to the pump inlet port as this can cause aeration of the fuel casuse the pump pressure to be eratic. For your return line I would go with either -6 or -8, another way is to use aluminum tubing and 37 1/2 degree AN flares. Pretty easy to bend, makes a nice looking installation, and reduces the amount of SST hose ($)you need.

Putting the fuel cell in the front helps keep the C of G forward which is good for stability.


Rex

Good stuff Rex, but personally I'll take exception with the no pre-filter.  I'm running an ......



......80 micron pre-filter right before the pump and......



.................. 10 micron filter after the pump between it and the regulator.  I agree with you want the pump as low as possible and my return line comes into the other side of the tank and returns all the way to the bottom of the tank on a line inside the tank.  All of my lines are -8AN  in anticipation of JH loaning me his 500+ HP 'busa  8-) .

Most of the info I've found from the pump manufactures and others recommends the pre-filter to protect the pump.

c ya,

Sum

Offline Rex Schimmer

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Re: I.F. fuel pump placement (question about distances)
« Reply #3 on: May 26, 2008, 04:29:21 PM »
Sum,
I still don't like inlet filters! 80 microns catches small children, birds and rocks! it is the 10 micron and smaller stuff that will wear out your pump and injectors.

A comment on your pressure regulator arrangement. Your regulator is a three port style, the inlet port and the outlet port are in line and straight thru the return port is tee'd  off of the inlet/outlet leg and bleeds off the required fuel to maintain the pressure that you set. Now looking at your set up I would assume that the outlet port of the regulator would go to the fuel rail and that the fuel rail will have a plug in the opposite end. This WILL trap air in the far end of the fuel rail, and although it will eventually desolve into the fuel it will casuse your system problems and it will not compensate for any pressure drop in the 10 micron filter. I would strongly suggest, as I did to Jonny, that you take the fuel line from the pump directly to the filter and then directly to the fuel rail and that the regulator be connected to the far end of the fuel rail. This insures that the pressure in the fuel rail is always what you set it at regardless of any pressure drop across the 10 micron filter and any possible line losses and it also assures that you never have an air lock in the fuel rail. Again, as I told Jonny, you simply connect the far end of the fuel rail to one of the inline ports of the regulator and then plug the other port and run the return port back to the fuel tank.

Like your blue lines!!

Rex
Rex

Not much matters and the rest doesn't matter at all.

Offline Sumner

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Re: I.F. fuel pump placement (question about distances)
« Reply #4 on: May 26, 2008, 05:19:54 PM »
Sum,
I still don't like inlet filters! 80 microns catches small children, birds and rocks! it is the 10 micron and smaller stuff that will wear out your pump and injectors.

A comment on your pressure regulator arrangement. Your regulator is a three port style, the inlet port and the outlet port are in line and straight thru the return port is tee'd  off of the inlet/outlet leg and bleeds off the required fuel to maintain the pressure that you set. Now looking at your set up I would assume that the outlet port of the regulator would go to the fuel rail and that the fuel rail will have a plug in the opposite end. This WILL trap air in the far end of the fuel rail, and although it will eventually desolve into the fuel it will casuse your system problems and it will not compensate for any pressure drop in the 10 micron filter. I would strongly suggest, as I did to Jonny, that you take the fuel line from the pump directly to the filter and then directly to the fuel rail and that the regulator be connected to the far end of the fuel rail. This insures that the pressure in the fuel rail is always what you set it at regardless of any pressure drop across the 10 micron filter and any possible line losses and it also assures that you never have an air lock in the fuel rail. Again, as I told Jonny, you simply connect the far end of the fuel rail to one of the inline ports of the regulator and then plug the other port and run the return port back to the fuel tank.

Like your blue lines!!

Rex

Thanks for the input.  I'll let you know if I have any problems with the filters.  The 80 is just suppose to help stop the rocks and birds from getting into the pump and the 10 will help with the injectors like you mentioned.  The GSXR-750 I'm using is setup to run as a dead head system from the factory.  It could be converted like you mentioned, but since I'm running it stock this year if running it at all I'll leave it that way and will put my time into just trying to finish the car.  When the 'busa motor goes in it will be plumbed like you mentioned.  I guess life is just full of compromises on this stuff.

What is everyone else doing that actually has a car/bike that is running??

c ya,

Sum

Offline maj

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Re: I.F. fuel pump placement (question about distances)
« Reply #5 on: May 26, 2008, 06:31:18 PM »
I like a flow thru fuel rail, esp on the bikes that can have fairly high under tank temps.
I also like some sort of coarse filter before the pump , made a 3" x ~3/8  ~80-100 micron strainer that is silver soldered inside the an6 tank fitting on  my racebike ,

Offline Stainless1

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Re: I.F. fuel pump placement (question about distances)
« Reply #6 on: May 26, 2008, 06:52:14 PM »
Sum and Jnuts,
For motor feed we have a Holley Red gravity fed from the tank with a -10 or 12, it pumps the fuel thru a 10 micron to the EFI fuel pump using a -8.  The EFI pump outlet is a -6, feeds the fuel rail, a -4 is attached to the other side of the rail and goes to the rising rate regulator.  We used this same system with the G motor NA and now it is on the H turbo motor.  
We had a fuel system issue caused by not feeding the EFI pump enough electricity for the turbo pressure requirements.  It would start to choke a little at the 55-60 psi range.  Our previous fuel system ran fine with #18 wire, the new pump requires about 20 amps to make 100 PSI (if I remember the spec sheet).  Changing to #8 and a 40A relay made it work great (we think).  We will see how it works on the Dyno, the white one....  8-)
Stainless
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Offline 38Chevy454

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Re: I.F. fuel pump placement (question about distances)
« Reply #7 on: June 03, 2008, 03:47:38 PM »
 
We had a fuel system issue caused by not feeding the EFI pump enough electricity for the turbo pressure requirements.  It would start to choke a little at the 55-60 psi range.  Our previous fuel system ran fine with #18 wire, the new pump requires about 20 amps to make 100 PSI (if I remember the spec sheet).  Changing to #8 and a 40A relay made it work great (we think).  We will see how it works on the Dyno, the white one....  8-)

That is a real important point.  The fuel pump needs maximum voltage so it does not start to require even more amps.  Remember the Volts x Amps = Watts (power) equation, so when your power is the same and voltage drops, the amps have to increase.  Causing the fuel pump to run hotter and increasing problems.  Good reminder for all.
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