To: Torque - BMW Forum

d3ity · 05-15-2004, 11:13 PM

Well, Building your own intake might not be as hard as it seemed!

I found a plan...

http://www.bimmermagazine.com/Technical/Intake.htm

Ok, so now the question becomes, where can I find a decent can style air filter that will not allow tons of shit into my engine, yet still provide good preformance?

Torque · 05-15-2004, 11:58 PM

ford focus svt filter looks like k&n filters. i dont know if it's better any.

d3ity · 05-16-2004, 12:04 AM

The quest for the perfect filter begins.

Also, another thing, What would make an effective heat shield?

Torque · 05-16-2004, 12:11 AM

i would probably start out with just a half of a larger can or sheet metal bent under 90 degrees. important thing is finding the filter... rest is pretty simple. i mean you can swap the new shield in after you make it in like 2 minutes.

d3ity · 05-16-2004, 12:34 AM

I was also thinking, once we get the cold air intake completed, how could we get more cold air to the filter, I'm thinking it may be possible to fit some sort of "scoop" down in the undercarrige area, mount it low on the front spoiler where it could get some decent airflow, then use tubing/piping to get the air sucked in from there back up toward the cold air intake. The only issues there would be the tubing would probably require cleaning, but its nature would probably not allow excessive dirt/debris into the intake area...

I'm gonna hammer out some sort of design on paint right now for such a device, some sort of shield might be helpful for keeping shit out of it, but it'd really just be for a little extra flow, so it couldn't really hurt anything. Forgive the overall shittiness of the design, but it gets the concept across.

Ok, finished that Idea, Tell me what you think of that, the way I see it, the cooler the intake air is, the bigger the gain we recieve.

Also, based on the air filter dispute, we basically want a filter that's more restrictive from the K&N, but less restrictive than the normal BMW one.

So my question becomes, do any BMW's use a conical air filter as OE?

d3ity · 05-16-2004, 12:50 AM

The short answer is No, no BMW's use conical air filters stock, now the question becomes, what kind of filter do I really want to use, and how much will it cost me to get one.

honestly i'd like to see an analasys of the AMSOIL filters and exactly what they filter out and show as flow rates...

Another option that i hadn't looked at is purolator, i use them in my e24 with fair results.

I cant find much info on the purolator, but I'm thinking this right now, so I may as well say it.

Either way I go it's going to be a trade off, Sure, the K&N filter allows more crap in my engine, but it has a higher flow rate than the stock filter, the AMSOIL filter has a similar flow rate, and similar filtration issues. If i go with a restrictive filter, I sacrifice some preformance, but gain a cleaner engine, which will give me better preformance in the long run. What I'd like is something in between the AMSOIL/K&N filter, and the BMW OEM Filter.

ghead

ghead I'd also like something relativley affordable, but the problem is finding what I need first, so i guess i can't really be picky.

SOOOOOOOO basically i've come to the conclusion that...

A. Preformance filters will allow too much debris into my engine
B. Stock filters are too flow restrictive to provide adequate preformance
C. I'm going to autozone tomorrow and reading some boxes of air filters that are lying around.

Torque · 05-16-2004, 12:53 AM

i like the idea of a scoop, but it wouldn't be easy. you would need a perfect design for air to be pushed to the proper side, and we are not engineers. also it would add wieght and would be too complicated to create piping that runs to it.

some people take their driver's side high beam out and stick the filter right behind the hole.

d3ity · 05-16-2004, 01:09 AM

The scoop idea shouldnt add that much more wieght provided you made it out of lightwieght components (plastics) and used sort of a cone shape to focus air into a point in the middle of the "dish", then simply pipe it back up into your engine compartment using some tubing..

God damn a dyno would be VERY helpful right now. But what the hell, i'm gonna try it, I figure, I keep the weight of the scoop down to a reasonable 4-6 lbs... I could get away with it... Taking out my spare tire would more than compensate for the additonal weight of the scoop.

Torque · 05-16-2004, 01:15 AM

I'll look around some auto parts stores tomorrow for stuff that could be used for all this.

going to sleep now. 2:10 am man

d3ity · 05-16-2004, 01:17 AM

good point!

Alas, i was at Advanced Auto today.

They have cone filters from Purolator, but they do not have any information on them.

Honestly, I think we may have to use K&N Filters. But I'm still looking for the perfect air filter.

The quest for the holy filter continues.

Might have something here... www.greenfilters.com

I've kept playing with the scoop idea, it looks fesiable, as long as I find a strong lightwieght plastic to make it out of, i have a hookup on the plastics end so I may be able to come up with something, I also need some sort of metal screen to keep shit out of it. a small stone getting sucked into it and flying into your filter would be a bad thing.

But once we find a filter I'm definatley gonna start construction of my intake and scoop.

Alin10123 · 10-23-2004, 01:40 AM

Quote:

Originally posted by d3ity@May 16 2004, 01:50 AM
The short answer is No, no BMW's use conical air filters stock, now the question becomes, what kind of filter do I really want to use, and how much will it cost me to get one.

honestly i'd like to see an analasys of the AMSOIL filters and exactly what they filter out and show as flow rates...

Another option that i hadn't looked at is purolator, i use them in my e24 with fair results.

I cant find much info on the purolator, but I'm thinking this right now, so I may as well say it.

Either way I go it's going to be a trade off, Sure, the K&N filter allows more crap in my engine, but it has a higher flow rate than the stock filter, the AMSOIL filter has a similar flow rate, and similar filtration issues. If i go with a restrictive filter, I sacrifice some preformance, but gain a cleaner engine, which will give me better preformance in the long run. What I'd like is something in between the AMSOIL/K&N filter, and the BMW OEM Filter. ghead ghead I'd also like something relativley affordable, but the problem is finding what I need first, so i guess i can't really be picky.

SOOOOOOOO basically i've come to the conclusion that...

A. Preformance filters will allow too much debris into my engine
B. Stock filters are too flow restrictive to provide adequate preformance
C. I'm going to autozone tomorrow and reading some boxes of air filters that are lying around.

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Um... amsoil's filters actually filter a lot better than the K&N filters. If you hold a K&N filter up to the sun, you can actually see light poking through the pores. But amsoil uses foam to catch the big particles and oil to catch the little particles. It's cleaner and it flows the same if not better than K&N. In a 4runner, my buddy ran some dynos on his, the K&N actually showed a decrease in power for him and an increase in an amsoil. Look on www.amsoil.com
They actually haev charts of the filter tests.

d3ity · 10-23-2004, 09:27 PM

Ahh, back from the grave.

Sadly, my scoop/K&N cone were both lost with my green 525i

I need to get around to making another one sometime soon. I'm using a K&N drop in right now. I'll definatley test the amsoil filters when I get around to it.

sp0rky · 10-26-2004, 01:54 AM

Making an intake for these cars is not a difficult task at all...

About filters, though.... Anything OEM from ANY company is a good filter.
K&Ns are good too, but on these cars be VERY careful not to over-oil anything, because that will kill your AFM rather fast and your car will start to idle / run terrible.

sp0rky · 10-26-2004, 01:58 AM

Thats another thing...

dont use foam filters if you drive aggressively or are exposed to severe weather changes - as they get brittle, your engine starts sucking in peices of them and they start to get smaller and smaller as a result until they filter less and less

About seeing the pores in the K&N, thats okay. Many filters are like that. If you look even closer, though - there are fibers which catch the dust. And remember, a K&N doesnt work on the pleats / fibers alone, they have to be oiled which causes the the fibers to be sticky.

I made my intake for mine over a year ago and it adds good performance in the UPPER RPM, takes away from torque NOTICEABLY, though. But I love it and the sound is great. I have a custom heat shield and the air is ducted from the side of the grill by the headlights to the filter (small opening, but does introduce colder air)

Remember to shield these from rain, that'll muck em up real bad real fast and winter driving will NOT be fun, I promise you that.