IS K&N AIR FILTER BAD FOR E30'S?

[j4ttluv]

I recently went to a bmw specialist, because as of late my car jerks violently when i put my foot down on the accelerator and eventuaLLY STALLS OR EVEN JUST THE CAR WONT START, NOW IVE CHANGED THE ICV AND PROBLEM STILL PERSISTS BUT WAS TOLD BY THE BMW SPECIALIST THAT K&N AIR FILTER ARE WORST AIR FILTERS TO GET BECAUSE THEY IMPREGNATE OIL ONTO THE AIR MASS FLOW METER AND CAUSES PROBLEMS FOR THE CAR AND HAS INSISTED THAT GETTING A COLD AIR INTAKE IS THE BEST OPTION AS K&N JUST SUCKS IN HOT AIR..IS THIS TRUE OR IS THE MECHANIC JUST TRYIN 2 SQUEEZE MY POCKETS FOR THE EXTRA PENNIES?? NE HELP OR EVEN NE HELP ON WHY MY CAR JERKS WHEN I PUT MY FOOT DOWN??

[Morat]

CAPS LOCK OFF PLEASE.

Try cleaning up your MAF and see if it helps. Cone filters are reckoned to be a bad thing unless properly heat shielded and not really worth it even then. Panel filter if you must, OE filter works very well as it is.

[GrindCulture]

I run a K&N panel filter in the standard airbox as my car had no air filter at all when I got it . No idea if it actually does anything to the figures, but it certainly feels a bit more punchy. Plus you wont need to replace it.

[oylegate]

You could cause a problem with the inake leaning out the mix and causing pinking. This is especially prevalent on older cars with crusty injectors.

[Fushion_Julz]

Nothing wrong with K&N...even if they don't offer any more performance they are "for life" and will be cheaper than paper elements in the long run...

E30s don't have MAF...they have an AFM (well, standard ones do, in any case)...Oil won't really affect the operation of these as it can't get into the potentiometer housing from the airflow path...

Panel types of filter that fit the standard airbox are better than cone types unless you construct a proper cold air feed...

[mattyray]

whats the best way to construct a proper cold air feed anyone?

[ed325i]

If its for a cone filter something like this.

[GrindCulture]

The original BMW airbox is pretty good at feeding cold air anyway, seeing as it's situated just behind the light, and if you have all the correct plates and tubes etc. there aren't really many ways that hot air can get into the airbox.

[mattyray]

i have a cone on str8 of the afm with no heat sheild was like this when i got car! is sucking all that hot air in damaging my car im sure its down on power?

[GrindCulture]

If it's a branded filter like K&N you could probably sell it, go to a scrappy or scout ebay for a proper airbox and do it that way. Unless you like the noise/appearance of the cone filter, then build a proper heatshield like ed demonstrated and see if that makes any difference.

[march109]

Your problem does not sound to be linked to the airfilter at all.

In fact it is a common problem experienced by many zoners including myself, the easiest thing to check are the rubber hose for splits between the filter and the throttle body, and the intake gasket.

Sounds like you have unmetered air leaking into your engine causing it to sort of bunny hop.

There a re a few similar threads on it.

However believing you never need to change your filter again because it is K&N is doubtfull to me at best. A paper filter is the best part of £4 and it actually FILTERS the air entering your engine. I know what I would rather use.

[mattyray]

i had the rubber hose of couple of weeks ago to clean it didnt notice any splits! when u say intake gasket im guessing its where the throttle body connects to the head would it be a good idea to whip it off and put a new gasket on i imangine they dont cost much?


also i dont have any of the original air box at all.

[78dude]

There have been issues where the oil who is on the KN filter have been trowed into the Air Flow Meter and you have then end up with an engine who dont run propperly! I had KN fliter on a Citroen XM 2.1 TD and it worked perfect for that car

[mattyray]

is it called the inlet manifold gasket i may need?

[Brianmoooore]

One of the inlet manifold gaskets may or may not have failed, but it would be sensible to actually check before you change them! There's no point and no gain in changing a perfectly serviceable gasket, or any other part, for that matter.
No E30 owner with anything like a standard engine has ever achieved any noticeable gains by replacing a CLEAN standard air filter with a K&N or any other make panel filter, cone filter, or whatever!
There are unsubstantiated reports of MAF assemblies being damaged by oil from 'reusable' or 'lifetime' filters, but since your car does not have a MAF (BMW specialist????), it's definitely not the problem with your car!
The biggest problem with these aftermarket filters is that they don't actually do a good job at what they are there for.

[markus_74]

I believe that replace the standart OE filter with cone filter will make me difficult to wash my engine bay, cause the water will splash the cone filter

[j4ttluv]

ok thats kool, ive just bought the standard bmw air filter from German swedish n french and am going to see if that will make any difference as its just the standard flat panel filter, ive also cleaned out the AMF so fingers crossed it doesnt bunny hop any more.thanks for the advice guys and if nothign still works i will be back to let y'all kno...cheerz!! WESTSIDE RYDERZ M4

[j4ttluv]

oK IVE JUST REALISED SOMETHIGN LOOKING AT THE AIR FILTER SHIELD PIC, I DONT HAVE THE cONE AT THE START OF THE INTAKE PIPE, I JUS HAVE A PIPE WICH OPENS WIDE LIKE A TRUMPET INSTRUMENT AND THATS IT BUT NO cone SHAPE FILTER:s...IM CONFUSED NOW...LOL

[e30bmlover]

i have a k+n panel filter in my b25 and it has made a little difference... i might take it out though... my thoughts about filters and performance parts are...... bmw spent millions developing these cars... so why change it?
i also have a spare k+n cone filter for a b25 ( it will never be attatched to my engine)