Cold Air Intake VS. Air Filter

[snowman9711]

What is the difference between getting a cold air intake as apposed to an air filter, because I see that alot of people on the forums have drop in air filters. Can you have both or only choose one. Which one is better performance wise.

[Boostin FD]

Many threads on this issue... Just search bud.

[tibra1]

[snowman9711]

well can someone just answer my question?

[Merlosso]

I'm not aware of any "cold air intakes" for the M3. Those are made for cars with restrictive air boxes that draw air from the hot engine bay. The intake on the M3 is about as open as it gets with all of the air coming from outside so really all you need is a drop in filter.

Take a look at the image in this post and you'll see what I mean:

http://www.m3post.com/forums/showpos...5&postcount=17

Note that there is very little power to gain from a filter but it will make it sound a little throatier.

[1sikbmr]

The factory air box on the M3 is probably the best design on the car. It has multiple points where cold air can get to the engine. Now the filter that they put is very restrictive so just a simple swap of the filter can gain some good numbers.

[THE TECH]

Originally Posted by tibra1

+1

[tibra1]

Originally Posted by snowman9711

well can someone just answer my question?

No

[CanAutM3]

Originally Posted by snowman9711

What is the difference between getting a cold air intake as apposed to an air filter, because I see that alot of people on the forums have drop in air filters. Can you have both or only choose one. Which one is better performance wise.

The M3 has a very well designed cold air intake from the factory.

is your friend here.

[crabman]

In a CAFE and escalating performance levels market OEMs have pretty much taken away the low hanging fruit so the days of mounting new cans or air filter housings (CA or not) and seeing worthwhile gains are pretty much gone on most cars. If you open up your hood and take a gander at the filter housing and its design a relevant degree isn't required to see its pretty darn good. IMO get the filter only if you want the slight increase with induction sound, otherwise skip both.

[1sikbmr]

Originally Posted by crabman

In a CAFE and escalating performance levels market OEMs have pretty much taken away the low hanging fruit so the days of mounting new cans or air filter housings (CA or not) and seeing worthwhile gains are pretty much gone on most cars. If you open up your hood and take a gander at the filter housing and its design a relevant degree isn't required to see its pretty darn good. IMO get the filter only if you want the slight increase with induction sound, otherwise skip both.

Actually there are some gains to the filter as well. Not much but it's there. The factory filter is very restrictive especially if you have an older year.

[Leonardo629]

M3 comes with a cold air intake from factory, gains have been seen with aftermarket high flow filter and bigger elbow tube..

[tom @ eas]

Originally Posted by Leonardo629

M3 comes with a cold air intake from factory, gains have been seen with aftermarket high flow filter and bigger elbow tube..

Exactly. The airbox leave very little on the table for improvement.

~10-12hp gains can be seen switching to the the Macht Schnell S2 intake, which retains the factory airbox.

[pbonsalb]

And those gains are from (1) scoops, (2) a supposedly higher flowing but actually physically smaller filter and (3) a slightly smoother molded plastic pipe to the engine inlet. Of these, scoops are highly questionable since there is already adequate air inlet and any extra air is not rammed in, but rather follows the path of least resistance and escapes through the hood vent. Less restrictive filters probably do flow better, and bigger ones than the Afe are available as drop in filters to the stock airbox and that fit on the stock inlet pipe. That leaves the smoother molding of the Afe inlet pipe. The stock pipe is so big that I really have a hard time believing there are gains to be had here.

[Verify]

Originally Posted by crabman

In a CAFE and escalating performance levels market OEMs have pretty much taken away the low hanging fruit so the days of mounting new cans or air filter housings (CA or not) and seeing worthwhile gains are pretty much gone on most cars. If you open up your hood and take a gander at the filter housing and its design a relevant degree isn't required to see its pretty darn good. IMO get the filter only if you want the slight increase with induction sound, otherwise skip both.

Tell that to new 5.0 owners...

[DiavelM3]

Originally Posted by tom @ eas

Exactly. The airbox leave very little on the table for improvement.

~10-12hp gains can be seen switching to the the Macht Schnell S2 intake, which retains the factory airbox.

Tom,
Aren't these intakes (Including the OEM intake) designed to move air into the intake system more efficiently while the car is in motion (Not a RAM air system but similar)?
Also, at what point would you do a tune (ECU tune like a Dinan)? After an intake, pulley, exhaust mod? Or would you do a tune after doing just an intake mod like this?

[Lorde]

Looking at the diagram, the stock airbox draws air from intake at the grille, intake at the driver side air duct, and drivers side hood "vent". All connect to the air box.

[sin911]

Originally Posted by Snig

Looking at the diagram, the stock airbox draws air from intake at the grille, intake at the driver side air duct, and drivers side hood "vent". All connect to the air box.

I don't know if the hood vent is actually supposed to draw more air in. Aerodynamically it will not be exposed to much air pressure. I think it is an actual vent for the excess air in the box.

[m3an]

Originally Posted by sin911

I don't know if the hood vent is actually supposed to draw more air in. Aerodynamically it will not be exposed to much air pressure. I think it is an actual vent for the excess air in the box.

yes, air is drawn through the front of the car and the hood vent allows for the air to leave the box. I would think that if it was closed up and a proper ram air setup utlized you would (at maybe over 100 mph) be forcing a slight amount of positive pressure on the airbox which would 100% be power making and noticeable. Keep in mind the bottom of the airbox also has a hole in it to drain water from that hole in the hood.

[tom @ eas]

Originally Posted by DiavelM3

Tom,
Aren't these intakes (Including the OEM intake) designed to move air into the intake system more efficiently while the car is in motion (Not a RAM air system but similar)?
Also, at what point would you do a tune (ECU tune like a Dinan)? After an intake, pulley, exhaust mod? Or would you do a tune after doing just an intake mod like this?

The stock airbox is very efficient, I have a hard time seeing any improvements being made. The plastic construction goes a long way to prevent thermal conductivity (ie: heatsoak). However, the connecting elements (filter, charge-pipes) are where the primary gains are being seen. On the software end, you should be on 231E.

Pulleys are different - they free up power rather than gain (less parasitic drag on engine). The end result is the same. you really can't go wrong.

On the exhaust side, catalytic converters rob HP on the M3 - as they are very restrictive. Switching to HFC or removing them altogether will show sizable gains and possible shave some unneeded weight.

[Ioannis]

so which one is better for the car talking about air filetrs and if it will benefit the car ?