K&N Fitted - do I benefit?

[MattieT]

Hi, I have bought a 1991 320 Baur and it is totally standard part from the K&N air filter.
I have concerns as the car is very slow and sluggish through the gears and only really lifts when on the mororway as speed. I also note that the exhaust is totally shot to pieces and this has the original CAT in the mid section.
QUESTION -
1. Is the K&N providing any value to me in any way?
2. Should I swap it back to factory?
3. Is the exhaust causing the issue because it is knackered?

[Cloggy Saint]

1. No
2. Yes
3. 320s are slow and sluggish at low revs

[rotta]

the cat could of broken down ect i had this on a previous car and by the time it was nearly dead it wouldnt pull the skin off a rice pudding, all you will gain from the k&n is some more induction noise no performance benefit best way to do this is original box and ram pipe and a high flow panel filter

[daimlerman]

320i is a very short stroke engine,so it develops it's power above 3000rpm.

[macas]

I know cone filters are shite.....because of heat from the engine etc,but what about proper induction kits like tge bmc type with the fresh air feed?...what are those like?

[rotta]

things like the gruppe m stuff and full carbon boxes on s50, 52, 38 ect work and do make numbers but i dont see you getting anything from an open unshielded cone, you could always fab something up to enclose the filter away from the engine temps and feed it nice cold air that would work.

[bosers]

I like to use the standard air box with a bmc panel filter, they seem well made and good quality. The first car I used one on, an Audi 80 sport, I definitely noticed a performance boost.
Having had one on a 320 and 325i I still think they're better than the paper ones but less noticeably, but they do last for years as you can clean them.
And yes, it's all above 4k for fun in the 320i.