intake piping

[Christo19]

what do you guys use for intake piping? I want to make a good cold air intake, and i would like the filter to end up behind the drivers side headlight. I dont want to go buy all that crome stuff from auto parts stores, costs to much and just not bmw worthy.

thanks
--Christo

[epmedia]

Check this thread - go to the link and notice the battery re-locate as well (unless you already did).

[Christo19]

what link?

[epmedia]

what link?

Oh Crap... Sorry about that..
This thread links to another site, that just shows some pics.
http://forums.bimmerforums.com/forum....php?t=1381047

I think the FAQ that JRCook put together on the e21 home page may also show some info.

[Christo19]

well how to i get or make that tubing

what do you think about haveing a exhaust shop bend some stainless steel piping ?

[milotrain]

Few things.
1. If you can't weld then making a CAI without using a bunch of silicone elbows will be difficult.
2. For a CAI system aluminum is sufficient and much cheaper than SS.
3. If you are going to pay someone to bend tubing then you should make sure that they mandrel bend it. (what mandrel bent tubing is) If this is what you want to do then mock up your CAI with PVC or similar in the size you want so you can take it to a shop and have them match its shape.
4. If you can weld then you can buy mandrel bent pieces like Us and elbows from suppliers like jegs and summitracing.
5. If you have an OA torch around and you are super old school and cool you could sand bend tube. See attached.

[Christo19]

ha i wish i could do #5, that would be pretty sweet, on monday i'll go talk to some shops and will try and get an aluminum one made

thanks

[milotrain]

Why not just lop the air box off the current intake tube, stick a silicone elbow on it and then another pipe to get you to a filter behind the headlight?

[Christo19]

i already have a big k&n air filter, and the elbo i have has a big crack

[DrewDude320i]

I have a TEP intake tube that I'm no longer using - I could sell it to you if you're interested. you'll have to move your battery to the trunk to use it, though.

[Layne]

5. If you have an OA torch around and you are super old school and cool you could sand bend tube.

Or you could buy the pre-made steel mandrel bends and just OA weld them together with about 1/10 as much difficulty.

[epmedia]

5. If you have an OA torch around and you are super old school and cool you could sand bend tube. See attached.

I did that in the '80s on a few pipes when I built a header exhaust for a '74 X19 Fiat. I kinked a few pipes though (scrap), cause I did not have a torch (just a stick welder). I lived on a sand top mountain, so it was sort of convenient.

[Christo19]

bad news, no one in my town does mandel bending, the pre made bends cost alot, if i just use big pipe will it be ok?

[milotrain]

Or you could buy the pre-made steel mandrel bends and just OA weld them together with about 1/10 as much difficulty.

See #4

However sand bending is just really damn cool. I don't think there is any reason to do it unless you feel like it, I can't really get behind a performance increase of not having seems at the welds.

bad news, no one in my town does mandel bending, the pre made bends cost alot, if i just use big pipe will it be ok?

It will weigh a ton. Buy Dude's TEP CAI and move the battery. Cheap and better than other alternatives it would seem.

[Christo19]

the pre made steel mandrel is not cheap, thats the problem, the guy i talked to today said he could bend 1/8 in thick aluminum pipe.

i'm waiting for the picture of the TEP intake, so we will see.

My battery is in the trunk

[milotrain]

http://www.summitracing.com/parts/HOK-12599HKR/

http://www.mandrel-bends.com/catalog...pler-1230.html

Use these two and a straight pipe. Not too expensive.

Milo

[jrcook320]

Here's the CAI I bought off ebay back in the day. It's very similar to the TEP unit. It's pretty simple, especially if you can weld. Two mandrel bends, a coupler, a mounting tab and a filter. You COULD buy two 3" mandrel bends and 2 couplers if you can't weld. Just cut them to fit and clamp them together as needed.

[bmac320i]

why run it behind the lights, go under the alternator and get some cold air

[jrcook320]

why run it behind the lights, go under the alternator and get some cold air

Explain why the air under the alternator is colder than the fresh air coming in through the grill?

the air under the alternator likely just traveled through the radiator, radiated off hot pavement and is further heated by a hot motor. There is no ambient temp air there. I'm not trying to be rude, I may be missing what you're thinking.

[Christo19]

i want my filter to end up so that the filter is in th same position as your new one jrcook, because i would like to make a air dam like yours as well

[DrewDude320i]

The TEP one puts your filter in the exact same place. I'll get you pictures tomorrow.

[epmedia]

i want my filter to end up so that the filter is in th same position as your new one jrcook, because i would like to make a air dam like yours as well

Excellent choice on JRCook's mod:

The hot pavement and water puddles are two, very important things to consider, which many folks forget about. Bottom line is - behind the head light, a box, and battery re-locate for e21s. I've never done it myself, but others have tested with guages and provided facts on similar setups.

[Layne]

The TEP one puts your filter in the exact same place. I'll get you pictures tomorrow.

Do not sell that thing, Drew. I think it can work temporarily as your turbo intake, otherwise you have nothing.

[bmac320i]

Explain why the air under the alternator is colder than the fresh air coming in through the grill?

the air under the alternator likely just traveled through the radiator, radiated off hot pavement and is further heated by a hot motor. There is no ambient temp air there. I'm not trying to be rude, I may be missing what you're thinking.

Sorry. ment more air .

[jrcook320]

I added a bunch of stuff to the faq thread including this thread. The faq was incredibly deficient on this topic.