In Tank Bosch 044 Fitting

[SmbFD3S]

Decided in the end to upgrage to the Bosch 044 and use this in tank.
 
First of all would like to say thank you to Jon at AtomicRex for supplying the parts and being on the end of the phone to discuss the setup and possibilities
 
This is the original fuel pump still on the bracket and the 044 next to it for comparison.  Have had the sock and adaptor already fitted in the photo.

 
Now the stock fuel pump is held in position with a bottom bracket and the outlet is a push fit with an O ring into the metal pipe that you see here

 
The pipe has to be cut in order to fit the 044 due to the size and then a piece of in tank hose can be used.  This has to be able to cope with being immersed in fuel.  Also got this from Atomic Rex
 
You want to cut the pipe about 2-3 inches from the top of the bracket (enough to get a good fit with a fuel pipe)
 
Now the Bosch 044 come with a fitted check valve on the top. This makes things a little bit awkward to fit. You have to put on a banjo fitting and from there you connect the fuel pipe to the bracket plate pipe you\'ve just cut.
 
Not pretty but looks like this

 
You can remove the check valve and fit an AN adaptor and feed straight up to the pipe but this means that fuel pressure can flow back through the pump which is not advisable.
 
There is also a fitting in Australia and the US called a Speedflow link here
http://www.furiousperformance.com.au/store/index.php?main_page=product_info&products_id=421
or
http://www.jayracing.com/index.php?main_page=product_info&products_id=227
and i may upgrade to this someday but when i spoke to Jays Racing the shipping alone was 38 dollars!!!
 
Anyway, moving on...
 
The standard wiring on the pump is 16 gauge, and this is unlikely to be able to cope with the new pump being as i\'ll be running 10 gauge from the battery to a new relay to feed it.
 
You can "unpin" the blue plug in the photo below, so i did this and got 2 new pins from Maplin and connected 12 gauge cable up.  The photo shows the original cables...

 
Next, i wanted to try and mount the pump as low in the tank as possible. Measuring from the top of the tank (where the bracket sits) the bottom of the tanks in built swirl pot, if you can call it that, is pretty much bang on 300mm.
 
I therefore decided to mount the pump so the bottom of the sock was at 290mm from the bracket.  This means there is some space underneath for it to "suck" but low enough for me to be happy with. Photo shows the top of the tank to the swirl tank.


 
I wanted to test the pump just to make sure it worked basically so hooked up the standard wiring to it and switched the ignition on, still using the 20amp fuse.  Fuel pump fired into life and primed successfully.  I shorted out the F/P and GND in the diagnosics to keep the pump running wo i coul dmeasure the amperage through the circuit.
at 13.4v i was seeing 15amps through the standard wiring and the standard earth cable within the loom was getting "warm".  This clearlyshows the standard loom was not up to the job.

With the fuel pump mounted and working i moved on to feeding new cables to it.  For this i used 10 gauge. This is fed from the battery to the boot and connects to a relay.  The original cables that fed the pump are cut and used to feed the switching relay so that it acts like stock i.e. fuel pump primes throgh the timing circuit.
 
At the fuel pump connector end i cut the red/white wire and ran a new 10 gauge wire from the relay and soldered this to the original wire (which is approx 12 gauge anyway and wouldn\'t make any difference over the short length)
 
The earth wire was cut at the connector and conencted to the bodywork via another 10 gauge cable.
 
Here is the circuit diagram i followed.

 
If you wanted to bypass the stock relays and still have the pump switched on ignition, you could sourc a 12v feed from something say like the cigarette lighter.  However, remember that this would not be timed therefore priming all the time on 2 ignition switch, just a thought. i.e. as below

 
I mounted my relay within the tool compartment in the boot for easy access should i need to replace it. I went for the Bosch 40amp so there is less likely chance of overheating it.
 
I have shorted out the speed relay using 2 spade connectors and some 10 gauge cable within the engine bay so that the "new" relay sees the full voltage and is bypassing the resistor. One less thing to go wrong as below...

 
With the new wiring in place and everything setup i measured the current again through the pump and at idle was seeing 8.8A at 13.6V. This was with the pump and the fuel cold tho so i would expect this to rise when warm.  I am sure the lower current is the result of the higher gauge wiring and ability to flow more current.
 
Put everything back together and went to get some fuel as the fuel light was on.  However this did prove that the Bosch 044 can flow even at about empty so thats always good to know.
 
Filled up and went for a drive, and everything seems to be good.  Fuel pressure is set to 40psi at the moment at idle (Vac line removed) and the car is now ready to me mapped
 
Hope this helps someone or just a good read for others
 
Again thanks to Jon at AtomicRex who had to put up with me moaning
initially that i didn;t think it would work, but after he setup a test rig at his own place/expense this gave me confidence
 
Cheers
 
Scott

[AtomicRex]

Excellent write up Scott
 
Well done for persevering with the set up

[SmbFD3S]

All worth it Jon and nowhere near as noisy as i thought it was gonna be, can\'t even here it inside the car

[philiwily]

Nice write up, cheers mate

[RobbieRX-7]

Nice write up man. Will come in use for lots of owners! This should be moved into technical stickies section!

[REW_D]

Hi Scott, I\'m just in the process of installing a Bosch pump in-tank and i\'m also doing the rewire.  I needed to ask you a couple of things and i\'ve sent you an email to see if you can help me out...
 
 
Cheers

[AtomicRex]

If Scott isnt able to help...you can always email or call me
 
Always happy to help

[DR SCHNITZEL]

I might get rid of my Walbro and get one of these as ive been told the walbro is a POS. Its 30% smaller that the standard pump!!! nice write up

[chrisJDM]

great write up

[Mehdi]

Excellent write up Scott..  I have fitted Bosch pump on my car , and have rewired everything similar to yours.
 
The bit I missed is the wire inside that tank, from the blue connector to the pump. I am guessing this is necessary to get the full current to the pump.
 
Did you have to get wire with any particular insulation, as I am wondering if petrol will deteriorate the rubber over time? If everyone just uses a wire with normal insulation good for taking 30amp, and had no problems, then thats what I will do.

[SmbFD3S]

Thanks for the comments mate
 
I\'ve since changed the connectors and got a wiring kit from Atomicrex but you\'ll have to either drill the top plate or buy a new one from Jon at Atomicrex.  This comes with the necessary cables, connectors and hermetically sealed grommet in which to use.
 
Just for interest i am also going to be changing the fuel pick up sock to something else as i had severe fuel starvation the other day on left handers as i only had a quarter tank (due to no swirl pot obv)  If you keep the tank above a quarter for everyday use it\'s fine.

[Mehdi]

Funny enough I also had starvation issues which confused me for a long time when it used to cut out. After realising this I had to measure the bottom of the tank properly, and take my time and position it low as possible but still with enough gap to suck the fuel.
 
I would also say keep at least half a tank if you are going to drive it hard. Worked for me.
 
I am also considering putting a Walbro instead as I am running less then 400bhp. It wont need the amount of current needed by Bocsh. I would still run the direct circuit through it (close to 13.6V) which will ensure maximum flow

[SmbFD3S]

I\'m also running less than 400bhp on standard twins, but with 4 x 850 injectors at 43psi.  No point changing for the Walbro IMO as you\'ll be no better off, the fuel circuit will still flow the same as the Bosch and you have the wiring to support it so it wont be an issue.  If you are running Stock fuel pressure\'s or just above the pump is nowhere near working it\'s limit anyway so it\'s not gonna be at maximum power usage

[Mehdi]

Cool .. i guess we are at the same level...
 
Ok.. the trouble is somehow not enough current is going to my Bosch. I have changed my wires and relays so many times with so many combinations. At one point it worked perfectly, and the car seriously flew.. ok.. well fastest i driven a car.. where the front wheels seem to lift
 
So its getting kind of hard to make the pump work right, cause it needs the current, where as any other pump which doesn\'t need much current will work fine on the same curcuit. But I probably also need to sit and fiddle some more with volt and ammeters to see if there is some weak spot.
 
So might try rewiring from blue connector to pump.. which maybe the causing the issue, as I never changed it   (But may not solve the problem as the connectors may also limit the current)
 
I am not too keen on changing the plate as well..  so if I can\'t get Bosch to work properly.. my backup plan will be the Walbro, wont be a better pump then Bosch.. but hopefully so long at it works

[SmbFD3S]

Interesting....
 
Have you wired it how i have above?  If all you\'re doing is switching a relay from the factory wiring then as you prob know you\'ll be getting direct current from you\'re newly installed 10 gauge cable to the pump.  
 
The voltage drop over 10 feet or so of cable (assume your battery is in the engine compartment still) will be next to nothing in the 10 gauge, which is why it\'s used and could actually carry up to 100A over 10 feet (in open air) so wouldn\'t worry about that.  You could actually use 14 gauge cable if you\'re battery was in the boot and this would be fine in theory and is the size of the cable connected in the original blue clip.
 
I had the original cables connected from the plate to the pump for about 8 months, ran 12 times down Santa Pod and has always been fine, and i only have a 20A fuse in now, so it\'s obv never taken any more than 20A.  
 
Did notice the other day however how loud the pump was after driving around for about 3 hours on throttle in the 28 degrees it was outside lol..... Fuel was pretty warm so the pump must have been....