Fuel Rail And Fuel Pumps

[Amaru]

Just a curiosity question (would ask mechanic but he is on holidays)...

If I am fitting a dual entry fuel rail, and the pump setup includes a Bosch 040 in tank and two external 044's, how are they plumbed up to the rail? One line running from each 044 to each end of the fuel rail and relief from the middle?

Are there any better or alternative ways of doing this?

Thanks

[djr81]

Just a curiosity question (would ask mechanic but he is on holidays)...

If I am fitting a dual entry fuel rail, and the pump setup includes a Bosch 040 in tank and two external 044's, how are they plumbed up to the rail? One line running from each 044 to each end of the fuel rail and relief from the middle?

Are there any better or alternative ways of doing this?

Thanks

<{POST_SNAPBACK}>

At the risk of asking a stupid question (There are no stupid questions, only stupid people ) why do you want to fit up two feeds to the fuel rail? When you use pumps in parallel (other than positive displacement pumps) you get a very small gain in flow for a huge gain in cost/power consumption etc.

Mostly fuel setup are as in the photo - with two pumps picking up from the tank & pumping to another small tank which is then always full. The third pump picks up from there & keeps the fuel rail pressurisedl at all times.

Edited January 31, 2006 by djr81

[Abo Bob]

He is talking about a pretty high power situation.

The only one I have seen like this is plumbed the way you mentioned nik.

You didn't mention a surge tank but I presume it's in there.

[Amaru]

Hi,

Thats why I am asking, as im not sure how it works. Currently there is the standard GTR pump in tank lifting to a surge tank, with a single 044 from the surge tank to the standard fuel rail.

Have since bought a HKS dual entry fuel rail and some pumps, my thinking was the 040 in tank pumping to the surge tank and the twin 044's pumping from the surge tank. Just not quite sure how they connect up to the fuel rail... do you join the two feeds together then split them again and feed it in to each end of the rail, do you keep them seperate from the 044's into each end of the rail?

Just trying to learn a bit, as for actual fitting, thats what I am paying the mechanic for

[djr81]

[Beer Baron]

do not go too overboard with the fuel unless it is an all out race/drag car as otherwise you will find you are pumping a lot of fuel around unnessesarily. this has the negative effect of heating the fuel (as it passes through the rail/engine bay) and eventually you have a whole tank full of hot fuel. which can hurt performance.

if it was me i would join the two pumps to a common line (possibly with a check valve after the outlet of each pump) then when that single line gets to the engine bay you split it in two and run a feed at each end and the reg/return from the middle. will you really need 3 044 pumps though? what size injectors are we talking about?

[Amaru]

Injectors are currently 700cc, probably need to go up in size as they will be too small.

Any other suggestions on pumping the fuel around for this power level? Bits and pieces I have to work with are: standard fuel rail, bosch 040, two bosch 044's, surge tank, hks twin entry fuel rail, standard fpr, sard fpr (the big RJ one).

[Beer Baron]

i don't think you will need that much pumping power to supply 700cc injectors. surge tank is definately a good idea (and make a large one if you are going to be doing extended WOT driving). sard fuel reg is a good idea too, and i really like the idea of twin feed rails as i'm sure you get much more even distribution of fuel throughout the 6 ports. some larger fuel lines could be a good idea too. i would think you could just use the GTR pump to fill the surge tank then use a single 044 to pump fuel to the engine bay then have a split with the two lines heading to each end of the rail, run the feed for the reg off the middle and return the fuel from the reg to the surge tank.

[Sydneykid]

The numbers tell the story.............

700 cc's X 6 = 4.2 litres per minute = 252 litres per hour

At 13.8 volts a single 044 will move 330 litres per hour at 73.5 PSI

So it will support 6 X 900 cc injectors at 2.4 bar boost with standard fuel pressure (36-38 psi)

So using 2 X 044's would lead to excessive fuel flow, even at 100% injector duty cycle. As BB quite rightly points out, that means hot fuel going around and around for no good reason.

cheers

[Amaru]

Cool so the general consensus is to run the single 044 from the surge tank and split it near the fuel rail for entry at each end.

Thanks for all the info

[PHaT MR30]

cool, i might just do this with my twin entry rail, means i can run the Reg off the middle outlet.

Sydneykid YOU are a wealth of knowledge!

[Beer Baron]

cool, i might just do this with my twin entry rail, means i can run the Reg off the middle outlet.

Sydneykid YOU are a wealth of knowledge!

<{POST_SNAPBACK}>

it;s the only smart way to run a twin entry rail. as far as i know that is the main advantage of a twin entry - more even flow to all injectors.

[PHaT MR30]

so what should i use to split the fuel line into two? a Y adaptor???

*sorry to steal thread amaru*

[Beer Baron]

yep, places like earls will have little fuel distribution blocks, or simply Y pieces you can use.