Fuel Filter

Patrick · #1 10th April 2006, 14:11

What fuel filter are you using?

I've got one of these from CBS -

I am wondering if its suitable for fuel injection consider I was a little off the mark with the pump!

The new pump as a 12mm input which is far too big for the filter anyway so I am looking at alternatives. I have found this but its a tad expensive!! :

https://www.burtonpower.com/dets_pro...=80014&PSet=98

But thats got me thinking - does it need 12mm pipes? The stock E30 system uses 8mm through out including the pump and fuel filter (its a giant over size one)

holgate86 · #2 10th April 2006, 20:28

Hi Patrick,
The fuel filter at the top of your page is for carb systems which only run at low pressure. If you are using an external fuel pump then you require 2 filters, one on the inlet port and one on the pressure side. The inlet filter protects the pump and the pressure filter the injectors etc. I found it difficult finding an inlet filter as most vehicles have them built into the pickup pipe in the tank, I stumbled on an ideal filter on an old AUDI 80 or 100 which had a 90 degree bend and pipe size of about 12mm and was only about £5.
The choice for pressure filter is easier, just take a look through a filter catalogue and pick the one that suits your application. I have piped my latest kit in hard nylon pipes so used a filter to match with push fittings.

hth

Brian

Patrick · #3 10th April 2006, 20:47

Hi Brian,

thanks for the info, this is getting more confusing! I wish I had a build manual with this sort of info in it!

Do you have any links or part numbers for the audi filter? Can you suggest a good place to get a high pressure filter? The only place I've found that lists them so far is burton power.

Thanks, Patrick

EDIT I've had a bit of a look on eBay there a few BMW specific high pressure filter on there so I'll probs get one of those.

EDIT2: I've had a bit of a look on http://www.gsfcarparts.com/ - is that audi filter on there? I've had a quick look but cant see anything that seems to fit.

peterux · #4 10th April 2006, 21:40

Hi Patrick,
I over indulged when it came to this. I picked up one of these.........

http://images.google.com/imgres?imgu...NA:en%26sa%3DN

But K&N don't seem to list them anymore and the end fittings cost me a small fortune!

I suggest you use the standard fuel filter as fitted to the original car. You can pick these up at any Halfords, or GSF, KMS, etc.

regards

Peter

Patrick · #5 11th April 2006, 07:13

Sounds like a plan, standard fuel filter it is

Just need a pre pump one now!

Patrick · #6 18th April 2006, 08:41

Brian - could you point me in the right direction for a pre pump filter on http://www.gsfcarparts.com/ please?

MartinClan · #7 18th April 2006, 10:11

I am also confused. Why use two filters? If you filter the fuel before the pump why do you then need to filter it again after? I don't see how the pump itself can introduce any muck into the fuel - unless you have to allow for particles of the pump vane wearing off - but surely these will be absoluletly miniscule.

Anyone?

Cheers

Robin

Patrick · #8 18th April 2006, 10:15

I had a look at the donor in tank pump and that has a fine mesh at the bottom of it to stop big particles - thats the only pre pump filtration I could see.

holgate86 · #9 19th April 2006, 17:14

Hi guys,
I will try and get the part number for you, it might require me getting under the Sportster which is not at home at the moment.
The reason for two filters is the prefilter just protects the pump from large dirt particles which could seize rotor, smaller particles are still allowed through which would damage the injectors etc so that's why a main filter is required, in fact there is even tiny filters in every injector.

cheers
brian

Patrick · #10 19th April 2006, 17:57

Quote:

Originally Posted by holgate86

in fact there is even tiny filters in every injector.

Thanks Brian

I guess that explains the reduction in flow rate on injectors as they age.

Patrick · #11 20th May 2006, 08:07

I got myself an Audi 100 fuel filter, but its got M14 threads on it (one side M12 in the filter with m12 to m14 adapter), and I cant find any 12mm fuel pipe unions for it

I've managed to find M10 unions with 12mm pipe connections though.

I can probably make adapters for the M12 end, but ive not got an m14 tap.

peterux · #12 20th May 2006, 22:54

Hi Patrick,
try Raceparts, they are fast mail order but the solution might be a tad expensive.

The only solution I can see is an 'M14 to JIC -6' adaptor and then add a 'JIC -6 push on hose' fitting.
http://www.raceparts-direct.com/prod...etric+Adaptors

Maybe give them a call, as they have a huge range of bits.

good luck, Peter

Patrick · #13 21st May 2006, 09:01

Thanks, I'm starting to think I should have just bought the expensive filter

all the bits and pieces are starting to add up.

peterux · #14 21st May 2006, 09:39

I know what you mean, it's all the little joiners, adaptors, clips, bolts, etc that add up !

Anyway, better get on, it's 'fitting the fuel gauge day', today.

Peter

Patrick · #15 22nd May 2006, 13:14

sod it, im buying the expensive one... atleast in future the filter paper will be cheap....

I had trouble with the fuel level sender gasket not sealing. I've used Hylomar blue: https://www.burtonpower.com/dets_pro...=90004&PSet=98 - although I've not tested the tank for leaks since I put that on,

MartinClan · #16 22nd May 2006, 16:22

Hey Patrick

I contacted FSE (01784 493555) (www.fuelsystem.co.uk) they supply nothing but fuel related components - in fact I suspect this is where Marlin get their pumps from. I asked for some technical advice and they were very helpful.

In the end I have decided to use their (FSE's) fuel swirl pot. It has a built in filter and looks like a properly engineered bit of kit. All I will need is a very fine post high pressure pump - pre injectors filter for which I intend to use the standard BMW one (about £5)

The guy at FSE told me that I didn't need a filter to protect the low pressure pump as it already has a gauze filter built in that is adequate. (This wasn't just bull as he asked me what type of low pressure pump I was using just to be sure)

So my final system will be:

Fuel tank
Red top low pressure pump (from Marlin)
FSE swirl pot
High pressure pump (from Marlin)
BMW filter
Injectors

Anyone want to buy my Marlin made swirl pot - going cheap

Robin

Patrick · #17 22nd May 2006, 18:45

I've already ordered, doh ! I guess we shall see what its like without the swirl pot. I still have a low pressure pump if I change my mind!

On the plus side I got the coil overs today & the door back from Marlin, although im leaving un packing the door till the weekend

peterux · #18 22nd May 2006, 20:43

OK, so we will have three different 'testbeds' to compare!

I am using Facet Redtop low pressue pump,
Marlin Swirl pot (mounted upside down, becuase it fitted better that way!),
K&N high pressure filter
and an FSE high pressure pump.

One things for sure, I won't be short of fuel pressure!

Thanks for the tip about the fuel sender sealing ring. I never did get to that this weekend as I got distracted fitting my coil, engine loom (again) and battery clamps.
Started de-rusting the old BMW horns. Not sure they are worth the effort but they still work great, so thought I would try to save them. One of the few non-BMW or Bosch parts. They are made by Fiamm, Italy. So I guess the Germans don't do horns??

happy building,

Peter

Patrick · #19 24th May 2006, 19:01

Small follow up on the fuel sender, just the blue stuff didnt seem to do it - probably didnt use enough. So now I've used the blue stuff with the rubber gasket which has done the job