87 White E30

[87 bmw 320i]

hey guys... im a new 1 to this forum and i think its great!!! anyways i was wondering if theres any point of putting a air filter in my 87 320i bmw. is there any suggestions that u guys hav???thanks

[325eXTATIC]

Originally posted by 87 bmw 320i@Aug 23 2005, 04:33 AM
hey guys... im a new 1 to this forum and i think its great!!! anyways i was wondering if theres any point of putting a air filter in my 87 320i bmw. is there any suggestions that u guys hav???thanks

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Air filters are VITAL to keeping your intake tract clean and preventing grit from getting into the cylinders and scoring them up causing you to lose compression (among MANY other issues!) If you are looking to improve airflow into the engine which can improve throttle response and power (a little bit) I would recommend something like a K&N high flow filter kit. They cost a bit more than a stock filter, but allow more airflow and you can "recharge" the filters whenever you want... They are cleanable filters, so you get a LOT of mileage out of one filter!
If you have a dirty filter, it is a good idea to at least get a new stock one if you can't afford a K&N or whatever, because the dirt trapped in the filter is robbing you of some airflow, and can reduce overall performance, so at the very least, replace your stock air filter every 3-5000 miles.
There are a few cold air induction kits out there for our cars, but honestly, the BMW intakes are not very restrictive, so you won't get too much of an improvement out of the $2-300 you would spend.

Hope this helps!!!

Josh W.

[offabroadway]

only 5000 miles on an air filter? used that doesn't seem right. I though it was something like every twelve months or 12,000 miles?

[325eXTATIC]

Originally posted by offabroadway@Aug 25 2005, 01:08 AM
only 5000 miles on an air filter? used that doesn't seem right. I though it was something like every twelve months or 12,000 miles?

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I admit, I am overly protective, and I think you are right on the 12000 mile thing, I actually use K&N filters, and I "recharge" them about every 5000 miles, since it costs next to nothing to do that, and it keeps the level of protection high. To be honest, I am willing to bet that more than 25% of the cars on American roads have NEVER had their air filters replaced. Sort of the "Out of Sight, out of Mind" mentality.

Josh W.

[DJProfessor]

after seeing a friend who religiously cleaned and oiled his K&N (every other oil change i believe, and he was doing oil changes at 2,500) on his older toyota supra and when he took out the motor to do a rebuild/upgrade and he looked at the impellers on the turbo and there was scars on it and such from where crap had gotten by the air filter i will never run with a K&N.......i mean think about it, why does it flow so good? it does because it is not filtering as much as the paper elements. and honestly if you took a new paper element and breathed thru it there really isn't that much restriction. my bmw project is going to be running the stock air box and stock element but i am running some duct work so that it gets a nice "ram-air" type charge. and honestly that's the best thing you could do for performance and still keep the engine as clean as possible.

[325eXTATIC]

Originally posted by DJProfessor@Aug 26 2005, 11:32 AM
after seeing a friend who religiously cleaned and oiled his K&N (every other oil change i believe, and he was doing oil changes at 2,500) on his older toyota supra and when he took out the motor to do a rebuild/upgrade and he looked at the impellers on the turbo and there was scars on it and such from where crap had gotten by the air filter i will never run with a K&N.......i mean think about it, why does it flow so good? it does because it is not filtering as much as the paper elements. and honestly if you took a new paper element and breathed thru it there really isn't that much restriction. my bmw project is going to be running the stock air box and stock element but i am running some duct work so that it gets a nice "ram-air" type charge. and honestly that's the best thing you could do for performance and still keep the engine as clean as possible.

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To some degree, I don't disagree DJ. On forced induction motors in particular, I think that is the case, because of the MUCH larger volume of air being pulled through the K&N element, more goo will get through. For any forced induction system, I usually wouldn't recommend an oiled gauze filter, but for our relatively limited lung capacity M20's, I don't think there is much harm. It keeps the big stuff out that could score my cylinder walls and reduce compression, and that works for me! Besides, we don't have delicate impellers rotating at nearly the speed of sound to beat the crap out of with microscopic schmutz.

Just one man's opinion...

Josh W.