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E39 performance air filter

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Evening all,

I've been looking at various air filters for the E39. Sellers claim they add BHP (normally minimal), better fuel consumption and make the car sound nicer when putting your foot to the floor.

I'm interested in the 'sound' enhancing factor. Do these filters really give a better sound to the car? If so, can anyone recommend any particular makes?

I look forward to your comments.

Sam

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Evening all,

I've been looking at various air filters for the E39. Sellers claim they add BHP (normally minimal), better fuel consumption and make the car sound nicer when putting your foot to the floor.

I'm interested in the 'sound' enhancing factor. Do these filters really give a better sound to the car? If so, can anyone recommend any particular makes?

I look forward to your comments.

Sam

Unless you are going down the induction kit and heat shield route, then there will be no difference in noise (ie: you use a replacement panel filter).

As for the ebay (just an assumption :lol: ) claims about better fuel consumption, etc....bollocks.

Unless it's heat-shielded properly, you won't get any better performance either - if anything, it'll be worse as it'll be sucking in hot air from the engine bay.

A proper induction kit with shield to feed it only cool air can make a marginal performance increase, but the additional noise is probably adding to the placebo effect of the modification to be honest.

The main restriction to airflow on the 523s and 528s is the inlet manifold and throttle body anyway, so putting a slightly more free flowing air filter prior to these elements really won't achieve a great deal.

Personally, I didn't go the induction kit route on my 5, even though i did on the 3, because the induction roar suited a tweaked 3 series coupe.....I thought it'd sound out of place on an e39 so didn't bother. After doing the inlet manifold and throttle body, I put in a K&N panel filter replacement.

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I am also running a K&N Panel Filter on mine.

Most performance filters are oiled.

There have been some reports that this damages the MAF.

However, I have had mine on for over 2 years now and its fine.

I think the damage has been caused due to people re-oiling them and over oiling them again.

I have never oiled mine again since new.

Performance wise, I found no difference to engine sound.

The car seemed to rev a bit better though but thats about it really.

When I first put it in - I thought what a waste of £35!

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I'm a skeptic. Filters limit the air flow because they are filters. It's easy to make a filter which is less restrictive but it's probably doing less filtering. In an era when car manufacturers are under immense pressure to achieve high mpg and low emissions it's probable they've made a careful filter selection. However, like everything it's a compromise as some people drive in a dustier environment than others. I tend to stick with standard air filters but make sure they stay clean. (Occasional remove, brush out or blow through backwards with an air line, and refit. Change at recommended interval.)

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This subject always gets a lively response.

True that standard filters are more restrictive than some performance filters but they do have a finer filter size. The performance types have bigger 'holes' so flow more air and use oil to attract particles rather than just catching them.

Running a classic with a K&N is fine, tolerances are coarser and you don't tend to do the high miles. I use K&N's with my 1973 MGBGTV8 and a K&N panel filter in my 528iSE (with the inlet trumpet removed). I do have a proper CAI filter kit for the 528 and yes it does make an awesome noise, it's the £80 per year my insurer wanted that got me to remove it! :x

If paper eliments were so good why do F1 teams use a K&N type panel filter, must flow better.

If you want some noise do something with your back box, much more rewarding! 8)

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Not numbered. The trumpet is next to part 7 and is held by two spring latches, one external (you can see the square hole above item 7 on the main housing) and the other is a bit awkward to get to but is on the inside opposite, you'll see.

The trumpet not only aims all the crude at the centre of the filter, which is crap, but also severly restricts the amount of air entering the airbox. I stopped at removing the tube duct 18 but some people have removed it and recommend it. Instead, they have fitted a hose from the spoiler grill area up to the airbox giving a good cold air supply which carries positive pressure; the standard system is a negative supply because it has to pull the air in.

The other item I removed was the silencer 12, I did have to turn an aluminium blanking plug to block up the hole in the inlet duct. I might point out the silencer had to be removed for the CAI kit.

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Did these DIY mods give any noticeable sound gains? I have removed some of the cold air ducting but found no noise difference at all...

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Did these DIY mods give any noticeable sound gains? I have removed some of the cold air ducting but found no noise difference at all...

With the silencer removed you do get a bit more noise and there was certainly a performance pickup when the trumpet was removed; using the K&N panel filter. On full chat there is more throttle noise but not nearly as much as from the CAI below.

http://i196.photobucket.com/albums/aa21 ... P00897.jpg

http://i196.photobucket.com/albums/aa21 ... P00893.jpg

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Thanks for the feedback guys... looks like I'll sack the air filter idea.

Someone suggested changing the back box for an improved sound? Has anyone 'upgraded' their back box on here? Can anyone recommend a good make/supplier at a decent price? Does changing the exhaust involve modifying the rear bumpber at all?

Thanks

Sam

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Thanks for the feedback guys... looks like I'll sack the air filter idea.

Someone suggested changing the back box for an improved sound? Has anyone 'upgraded' their back box on here? Can anyone recommend a good make/supplier at a decent price? Does changing the exhaust involve modifying the rear bumpber at all?

Thanks

Sam

I have a Scorpion back box which has twin 3" tailpipes. These are cut up into the bottom of the bumper stopping at the groove. Personally I feel the car needed tailpipes and when I fitted the towbar (removable hitch type) the removal of the standard twin backboxes seemed a good way to save weight and get my tailpipes. :D

http://i196.photobucket.com/albums/aa21 ... C_0351.jpg

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well i've just blocked off the intake silencer( bodged with some leccy tape, i know i know :-)) and removed the trumpet and it sounds oh so nice :-) just hope the tape doesn't get sucked into the intake!

No performance gains at all, maybe a little worse than before...

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well i've just blocked off the intake silencer( bodged with some leccy tape, i know i know :-)) and removed the trumpet and it sounds oh so nice :-) just hope the tape doesn't get sucked into the intake!

No performance gains at all, maybe a little worse than before...

Shouldn't do anything detrimental to it's performance or the running. Might need the odd moment for the computer to suss the extra air but, you're trying to make a noise with it rather than drive it normally! :lol: Take it out on the road and crank it up to 6000 and you'll hear it crawl more, it changes the exhaust note too but that's much better with the back box done. :D

You need a 48mm dia plug to sort the silencer hole bodge, I turned mine from aluminium. Have you still got the paper element in or have you fitted the K&N?

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On 5/9/2007 at 5:01 PM, rtfacts1 said:

Not numbered. The trumpet is next to part 7 and is held by two spring latches, one external (you can see the square hole above item 7 on the main housing) and the other is a bit awkward to get to but is on the inside opposite, you'll see.

The trumpet not only aims all the crude at the centre of the filter, which is crap, but also severly restricts the amount of air entering the airbox. I stopped at removing the tube duct 18 but some people have removed it and recommend it. Instead, they have fitted a hose from the spoiler grill area up to the airbox giving a good cold air supply which carries positive pressure; the standard system is a negative supply because it has to pull the air in.

The other item I removed was the silencer 12, I did have to turn an aluminium blanking plug to block up the hole in the inlet duct. I might point out the silencer had to be removed for the CAI kit.

Very interested to understand this Airbox mod, I did a similar thing on my previous Seat Cupra airbox by smoothing the internals as I didn't want the downside of heat soke by using a cone filter. 

Your topic mentions numbers but no pics. Perhaps you could elaberate ?

Thanks 

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5 minutes ago, domin8or said:

Very interested to understand this Airbox mod, I did a similar thing on my previous Seat Cupra airbox by smoothing the internals as I didn't want the downside of heat soke by using a cone filter. 

Your topic mentions numbers but no pics. Perhaps you could elaberate ?

Thanks 

 

Have a look at my CAI effort in my projects; on last page I think

 

I've now sourced an undamaged OEM intake box; but will leave it as it is for now, not notice any issues with heat soak at all seeing as the filter fits into the air feed tube

 

Remove the resonator with a Z3 3.0i intake pipe as well; makes it look a cleaner system then  IMO

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45 minutes ago, domin8or said:

Very interested to understand this Airbox mod, I did a similar thing on my previous Seat Cupra airbox by smoothing the internals as I didn't want the downside of heat soke by using a cone filter. 

Your topic mentions numbers but no pics. Perhaps you could elaberate ?

Thanks 

 

Click on the link in my sig below pal

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On ‎5‎/‎9‎/‎2007 at 1:23 PM, rtfacts1 said:

If paper eliments were so good why do F1 teams use a K&N type panel filter, must flow better.

 

 

At a guess:  they are putting out over 900bhp so their appetite for air is huge, much more than your standard road car.

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On 7/3/2018 at 6:33 PM, domin8or said:

Very interested to understand this Airbox mod, I did a similar thing on my previous Seat Cupra airbox by smoothing the internals as I didn't want the downside of heat soke by using a cone filter. 

Your topic mentions numbers but no pics. Perhaps you could elaberate ?

Thanks 

This thread is over 11 years old! :shock: 

talk about a thread from the dead.....

Wow! 

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Ok, so full mod done, as I had a dodgy intake pipe to change anyway.

IMG_0714.thumb.JPG.c42960eb9dbb6372f0acb74081945f9d.JPG

So I ordered a new intake pipe (before I read you can get one without the connection for the resonator, however at least I can change back if required), Next was to find something to blank the resonator connection,so into the shed I went, and found an old bearing end cap, perfect, so a wee coat of paint & a jubilee clip and we're sorted.

IMG_0715.thumb.JPG.9f2dd85ad481667303a0193465000eb4.JPG

Fitted this onto intake pipe,using a wee bit of waterproof grease to help with fitting as was nice & snug (45mm internal size).

IMG_0718.thumb.JPG.67ce0eb833ec8891c3747095eff6be1f.JPG

Job done,fitted back in car,can hear a bit more induction noise,will know better when car all done & ready for use as my daily.

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