Author Topic: Using Other Stock BMW Air Filter Boxes? (Read 3278 times)

bmwman91 · « **on:** May 11, 2012, 05:05:43 PM »

So I am hoping to keep a very stock look on the motor I am having built, and one area of concern is the air filter. Being that my new motor can flow close to 50% more air than a stock M42, I am thinking that using the stock air box might not be great for power. Considering how much time and money the new motor is costing, it seems silly to risk power losses from the use of the stock intake when a big cone filter is cheap & easy to fit in there. A stock M42 does just fine from the stock air box & AFM, but this built motor will be getting one of my custom MAF conversions since I think that a somewhat more free-flowing sensor would be beneficial there.

Sticking an open element filter on is no problem. But, a nice stock look (and the fact that the stock airbox IS a cold air intake) would be awesome. I sort of doubbt that the stock size paper panel filter will be good for that much more air flow. Something like an M30 filter might be better. Has anyone ever swapped in the air box from a larger motor?

DesktopDave · « **Reply #1 on:** May 11, 2012, 05:51:46 PM »

Not me, but I have an M20 box I can take some measurements from. I'll bet it's the same box.

I also have an M30 box on my 633CSi, but it's a very different sort of beast...not suitable for mounting in the e30. An e34 535i would likely be a good bet.

MLM · « **Reply #2 on:** May 12, 2012, 05:40:14 AM »

Just bought a 318ti yesterday and noticed the filter box is alot larger than the one in my IS, both e36 m42's. the filter is as wide as it is deep.

I know you have an e30 but the k&n from the 36 318is filter went into my e30 air 318i housing no problem.

At a guess i would sat the TI airbox would drop in with no mods (same mounts + location as e30 chassis) and gain you approx a 50% filter area increase.

bmwman91 · « **Reply #3 on:** May 12, 2012, 05:40:19 PM »

Thanks for the input guys.

Would any of you be able to take some pictures of the aforementioned air boxes from the E34 535i & E36 318ti? Even in-car pics would be fine.

The 318ti air box actually sounds like a good idea since it used a MAF and has a little velocity stack thing & resonator on it that was designed to help a MAF cope with the M42's unique intake quirks.

MLM · « **Reply #4 on:** May 12, 2012, 07:22:27 PM »

Sure can take a picture for you.

I dont seem to be able to upload pics here. It may be because im newish with a low post count, or im ballsing it up somehow. Is there somthing I should know or do?

Failing that PM me your email and I will send direct.

DesktopDave · « **Reply #5 on:** May 12, 2012, 08:48:23 PM »

Attachments are disabled for some reason. I use Photobucket & paste the thumbnail HTML directly into my posts.

bmwman91 · « **Reply #6 on:** May 12, 2012, 10:58:39 PM »

Any chance that someone could get me the dimensions of some of these air filter panels?

The 318ti box looks neat, but the side inlet might complicate things. I saw some pics of the E34 535i box on eBay and it might be a better candidate.

MLM · « **Reply #7 on:** May 13, 2012, 02:31:28 AM »

The TI filter is 235 x 235 mm. Its a M42 engine with normal door style AFM,

bmwman91 · « **Reply #8 on:** May 13, 2012, 03:56:00 AM »

Aaah, so it's a 1995 model? Thanks for the measurements! I will scour eBay for some pictures!

MLM · « **Reply #9 on:** May 13, 2012, 04:55:59 AM »

Actually its 96... I thought the change over date was in 95 too...

Oh well another M42 in the family