stock airbox is the best option.

[LowR3V'in]

Hi, just wanted to say that I had to use a cone filter for some reason
and first thing I noticed that street driving it'll go right up to 150*F but will
go down to about 130*f on a long straight cruise staying at that temp.

Compared to a constant 85*F to 90*F with a stock box.

How about restrictions?
The stock air box has no restriction over a cone filter. Vacuum was the same give or take 1-2kpa with
a cone and even just open throttle body.

So just posting to say get a stock airbox if you're using a cone filter at the end of your afm. :)

[ttrousdell]

The increase in air flow through a cone style air filter is small. It doesn't produce that much hp gain and you have to suck hot air (less dense) from the engine bay unless you fab some kind of barrier between it and the rest of the engine bay. I kept my stock air box and it fits nicely once you move the coil a few inches back.

[Jb325is]

I run the stock airbox too, just watch the plug wires with it. My #1 wire arced off the heat shield on the bottom side of the airbox

[LowR3V'in]

The increase in air flow through a cone style air filter is small. It doesn't produce that much hp gain

Doesn't produce any horseopower and 0 increase in airflow.

[mr.vang]

so you did some kind of temp testing? can you take out the high beam and see if there is any temp/vacuum difference at high speed?

[LowR3V'in]

Like ricer style?
I don't have the setup anymore but if you're breathing in underhood air everywhere
except just high speed freeway runs what's the point really. Pure rice man, you get NO power over the stock airbox. Best thing you can do is put some heat shielding around it
from where it goes over the engine.

Heat won't effect vacuum so it'll still be the same. The throttle body is somewhat of a restriction though but can't really do anything about that.

[Doughnut]

Nah, cone filters are the best when I put mine on I got instant 20+HP gains, sounds like a turbo when you r3v the engine, I'm going to make a kustom intake with two! cone filters!!

Stock air boxes are shit.

[devon.818]

does this applie if you have a MAF conversion?
i have maf conversion and kamotors intake, my temp stays right between the 1/2 and 1/2 way mark on normal days, stays at just to the left of the half way on HOT HOT HOT HUMID days. then creeps to half way if i sit in traffic.


stock air box for stock motor.

[StereoInstaller1]

WTF does coolant temp have to do with intake temp? I mean, yeah, of course the temps will rise if it is hotter, but that is just retarded.

Get a thermocouple and test it if it really matters that much...but cone filters are retarded anyway.

[Earendil]

does this applie if you have a MAF conversion?
i have maf conversion and kamotors intake, my temp stays right between the 1/2 and 1/2 way mark on normal days, stays at just to the left of the half way on HOT HOT HOT HUMID days. then creeps to half way if i sit in traffic.

And the "wtf" post of the day goes to...

Devon, I think you misunderstood the OP. He had a temp sensor sitting inside the stock airbox. He isn't talking about the coolant temp :)

[Earendil]

Nah, cone filters are the best when I put mine on I got instant 20+HP gains, sounds like a turbo when you r3v the engine, I'm going to make a kustom intake with two! cone filters!!

Stock air boxes are shit.

And how did you measure that "20+" ? Butt dyno?

I do remember reading that the little "Cone" inside the stock airbox is required to get the air flowing properly. Turns out Engineers know what they're doing
A person actually ON a dyno measured an 8-10hp drop when that internal cone was removed. No citation, I'm too lazy to use google.

[devon.818]

And the "wtf" post of the day goes to...

Devon, I think you misunderstood the OP. He had a temp sensor sitting inside the stock airbox. He isn't talking about the coolant temp :)

hahahaha oh thats cool.
actually makes me want to test my intake now.

sorry guys, ignore my bullshit post!

[CorvallisBMW]

I use the stock airbox. Not only does it keep intake air cooler, it looks better than a bright red stubby phalice.

[Doughnut]

And how did you measure that "20+" ? Butt dyno?

I do remember reading that the little "Cone" inside the stock airbox is required to get the air flowing properly. Turns out Engineers know what they're doing
A person actually ON a dyno measured an 8-10hp drop when that internal cone was removed. No citation, I'm too lazy to use google.

When I had the stock airbox on and I street raced my buddy in his Subaru STi I could never win.
But since I put the cone filter on I blow past him every time, I can go 20kmph faster that him and 1HP is equal too 1kmph so YOU do the math.

BMW Engineers had no idea...

[VinniE30]

When I had the stock airbox on and I street raced my buddy in his Subaru STi I could never win.
But since I put the cone filter on I blow past him every time, I can go 20kmph faster that him and 1HP is equal too 1kmph so YOU do the math.

BMW Engineers had no idea...

Wow you can really beat a stock sti with an m30 e30? Impressive. What's your setup? mods? weight?