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Discussion Starter · #1 · (Edited)
Hi,

So, I spent some time replacing the pre filters in my sytec bullet filters and cleaned out the post filters.

This is the state of the paper filter that came out: -



Disgusting!

This could be the reason why the fuel pressure was dropping at high rpm/boost on the dyno after there was some residual heat in the system but I'll keep track of it because there could be a number of other reasons. I didn't bother changing the lift pump filter as I think that these don't tend to get that dirty and it's not been in long.

So that paper filter in the image is 8 microns which was sitting before the 044 bosch pump. This isn't really ideal, as I've subsequently found out that it can cause the pump to work quite a lot harder and could limit life (probably causing some level of vapour lock as well). What I've done is dropped in a stainless steel 55micron pre filter into the sytec bullets and cleaned up the post filters. The 044 pumps have a 20micron filter built in and the post filters (35micron) should hopefully catch anything if the pump decides to go bang (my injectors are more expensive than the pump)

The ID1000s I have should have 7micron replaceable filters in the adapters which I should actually check because I haven't checked since they went on! There's nothing filtering to that granularity before though so maybe I need to have a think about putting something before the greddy fuel rail.

Hoping someone can do a sanity check on what I've done here as I hopefully should have all bases covered: -

injectors - safe 20 micron post pump then 7micron filtered per injector
pumps - safe - filtered from lift pump - filtered at 55micron, filtered on the pump at 20micron
possible improvement - 8 micron fuel filter on each entrance to the fuel rail? (seems a bit over the top)

Sound ok? Most of this is self taught and DIY in spare time.

Thanks!
 

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I've never been a massive fan of fuel filters.
Why not just use the injector filters?
 

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Discussion Starter · #4 ·
The goal would be to stop larger debris prior to the injectors; moreover, the injector adaptors with the built in filters are quite expensive!
 

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Where is the debris coming from? Can you tackle that?
 

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Discussion Starter · #6 ·
I was under the impression that fuel was generally quite dirty (grimey/foreign objects/etc)

It's either putting trust in the corporations that sell fuel, or accepting that there may be debris and filtering it yourself.
 

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Quite a few modern cars do not have fuel filters.
 

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Discussion Starter · #8 ·
That's interesting to know, I wasn't aware of that. Perhaps I'm being a little over cautious.
 

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It's a double edge sword. Pushing fuel through a filter reduces flow and increases back pressure. Both undesirable.

Just my two penny's worth.
 

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Discussion Starter · #10 ·
I appreciate your view! I'll monitor how it goes. I was a bit worried about not having anything less than 20micron before the injectors.

Thanks for the feedback! I've got to pop out so won't be able to reply until later if anyone else posts.
 

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Discussion Starter · #12 ·
So I've made a mistake in what I wrote..

The injectors don't actually have the 7micron adapters and the bosch 044 pumps only have the 20micron filter if they're in-tank.. doh!

That means that I'm only filtering the fuel to 55micron granularity pre-pump.

I appreciate that people are suggesting not to use pumps but I saw: -

Fuel System Filtration : Injector Dynamics Support

Does this not imply that I really 'should' be using that 8micron filter pre-pump?
 

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Post pump really.. If you do run an 8 micron filter get a huge one (the more filter area the less restriction to flow).

My stock GTO filter was nearly the size of the oil filter..

I go down to 20 microns post pump and just called it a day at that, my Bosch ev14 930's have filters but doubt they are 8 micron..
 

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If you really want to go mad I can sort you a 1 micron filter and alloy holder/bowl assy.

Total overkill on petrol injectors though dude.

Petrol can laquer and drop the lubricity improver out of solution but it will have been been through 1000s of heat and pressure cycles to ever be that bad.

Same for old/stale fuels.

The petrol top/side feed inj have a gauze filter on the inlet prior to the pintles , again will catch all debris large enough to cause an issue.

My 5yen..... HTH
 

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Hi,

So, I spent some time replacing the pre filters in my sytec bullet filters and cleaned out the post filters.

This is the state of the paper filter that came out: -



Disgusting!
You think that is bad lol.

 

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i think the key here is to change the filters on a more regular basis the same as oil,as i don't believe manufactures when they say that the oil is good for a year,as surely it depends on how you use your car and how hard you drive your car.so on that basis i change my oil and filters a lot more than suggested,especially when they are paper.

just my opinion mind you.

simon
 

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Discussion Starter · #17 ·
eek, that does look bad and yes, changing regularly seems to be key.

I'm going to drop the 35 micron filter in today after the pump as these injectors don't have the filter mesh and ID do quote that anything above 35 can damage them.

Better to be safe I think but for me, I think the 7 micron behind the pumps was the problem with the fuelling
 

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Discussion Starter · #18 ·
So I've had word back from an e-mail I sent to injector dynamics and they have stated that 35micron post pump filters are not enough to protect the injectors even though the article below says anything OVER 35micron will cause injector damage.

I do have the blue adapters but I can't be sure whether or not they contain the 7micron basket filters. I suppose my safest option is to take the fuel rail off and inspect the adapter personally.

http://i.imgur.com/XwgVgfm.jpg

It does seem, upon reading, Fuel System Filtration : Injector Dynamics Support, that they do recommend very fine filters before the injectors.

"Recommended filter quality: nominal rating 5µ, minimum 82% capture efficiency according to ISO/TR
19438; dirt particles >35µ are not permissible. The basket filter in the injector serves only to catch
residual particles. Nonconformance of the recommended filter quality can cause damage to and failure of
the components"

Thoughts?
 
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