aFe intake for Z4M - a MUST mod

[thekurgan]

Originally Posted by erhanh

As far as I know, the DME can adapt itself to these sort of changes (and it should if you think about the weather temp difference between summer and winter, or the elevation changes etc).

That's what I was thinking, temperature shouldn't be that large of an issue, but overall airflow and expected airflow from the stock airbox could be the issue. I'm only basing this on the SIB stating that if the charcoal filter is removed, airflow is disturbed and strange things happen. Would like to hear a sound clip from this thing in action though.

[GP20]

It's not just a matter of putting insulation around the box. With the AFE intake you lose the ram-air effect which essentially acts like a very very tiny supercharger, especially at higher speeds with higher air pressure. This is the main reason that intakes like the AFE actually loses power compared to the stock airbox. Now if you can find a way to seal the box...

[hansaysso]

Originally Posted by GP20

It's not just a matter of putting insulation around the box. With the AFE intake you lose the ram-air effect which essentially acts like a very very tiny supercharger, especially at higher speeds with higher air pressure. This is the main reason that intakes like the AFE actually loses power compared to the stock airbox. Now if you can find a way to seal the box...

would this still be the case when something like an AFE intake is combined with the RPi intake scoop?

[Serious]

Originally Posted by GP20

It's not just a matter of putting insulation around the box. With the AFE intake you lose the ram-air effect which essentially acts like a very very tiny supercharger, especially at higher speeds with higher air pressure. This is the main reason that intakes like the AFE actually loses power compared to the stock airbox. Now if you can find a way to seal the box...

The point of the scoops isn't to ram air into the engine, which is under vacuum remember, its to allow the intake to channel the air as efficiently as possible.

If you look at the intake designs of the e9x m3 and e46 m3 they actually have holes to allow the air to escape the airbox, essentially sucking away all the air that would be "rammed" into the intake. Intake tuning is alot like drinking water out of a hose, if you just turn water pressure to max and blast yourself in the face it's very difficult to drink, likewise if you don't have enough flow of water there isn't enough to drink, what you want is to find that balance of flow between too much where you can't swallow it all and not enough where you are taking small sips. Intake tuning is exactly the same idea. Look at all race cars every channel and duct is designed to channel air either into or around components or body & aero components.

on the job of the component.Ram air is a marketing term. Which is why I don't trust aftermarket intakes which aren't designed using the same CFD analysis as the stock stuff, and I just don't think some dude in his garage can design something better then a team of BMW's engineers.

[GP20]

Who's saying anything about the scoop? I thought this thread is about the AFE intake?

The hole in the stock box is to drain out water/rain. It makes no difference to the "fact" that there's air-pressure building up in the stock airbox; the size of the hole just changes the amount of the pressure. You can say the term ram-air effect is a marketing term. But physics is physics.

Edit: Nevermind I think you meant to reply to hansaysso.

[Serious]

Originally Posted by GP20

Who's saying anything about the scoop? I thought this thread is about the AFE intake?

I was referring to the stock scoops and ducting and how they actually don't function to "ram" air at all.

[GP20]

Originally Posted by Serious

......and I just don't think some dude in his garage can design something better then a team of BMW's engineers.

You're right; some dude can't just do that in his garage. It'd take a lot of money, time and R&D. Not exactly something worth investing on for a car like the Z4. Which is why you see all the aftermarket companies simply come out with easily designed and manufactured hot-air intakes that make the cars sound nice while losing power at the same time.

[GP20]

Originally Posted by Serious

I was referring to the stock scoops and ducting and how they actually don't function to "ram" air at all.

Then you'd need to do more research on how the stock airbox works as well as the physics behind rammed air - 'cos you don't actually know what you're talking about.

[Serious]

Originally Posted by GP20

Then you'd need to do more research on how the stock airbox works as well as the physics behind rammed air - 'cos you don't actually know what you're talking about.

I understand the theory behind the concept of ram air just fine, I (and the BMW engineers based on recent designs) just don't think it works as advertised.

It is commonly thought that the purpose of this is to 'ram' air into the engine like a supercharger, but the airbox does the opposite. The carbon fibre duct (1) gradually widens out as it approaches the engine, effectively creating a venturi and a suction effect on the small air inlet. The shape of this ducts and inlet however must be carefullly designed to both fill all cylinders equally

http://www.f1technical.net/articles/4

Look at the design of the intake on the e9x m3 (and e46 m3 although it isn't as clear) there is a high pressure area on the front of the car where the air is drawn in, on the e9x m3 it has a hole cut in the hood, which is a notorious low pressure area at speed so, why would you want an air intake in a low pressure area?... its to allows the air being throught the 2 intakes in the front (behind the grills and drivers side brake duct) to escape, this allows more laminar flow and reduction in turbulence.

[pokeybritches]

What we need is a video of a stock car vs. an aFe car. Any dramatic horsepower differences should show up there. I've seen a thread on a 5 series forum claiming that the aFe lost 30 hp or so, which I think is total BS. I'm as skeptical as anyone with regards to claimed hp gains, but I've seen post after post of rival companies saying aFe loses serious power (it doesn't). From what I could tell, those tests were disgustingly biased and anything but scientific. On one dyno the car was run hard time after time with no cool down period in order to intentionally induce heat soak and SURPRISE inlet air temps were around 140 degrees = loss of hp.

I think the best way to test if the car loses power is to run 2 cars with equal weight drivers in say a 2nd or 3rd gear pull. I bet the results will be pretty close. If anyone in the Fresno area has a stock car that would like to donate their time, I'm down to donate mine as well. Otherwise it'll probably be up to the SoCal members as your Z density is quite a bit higher

As I've said before, the aFe probably doesn't gain any power, but there's definitely not a huge loss in power either.

[Serious]

Originally Posted by pokeybritches

What we need is a video of a stock car vs. an aFe car. Any dramatic horsepower differences should show up there. I've seen a thread on a 5 series forum claiming that the aFe lost 30 hp or so, which I think is total BS. I'm as skeptical as anyone with regards to claimed hp gains, but I've seen post after post of rival companies saying aFe loses serious power (it doesn't). From what I could tell, those tests were disgustingly biased and anything but scientific. On one dyno the car was run hard time after time with no cool down period in order to intentionally induce heat soak and SURPRISE inlet air temps were around 140 degrees = loss of hp.

I think the best way to test if the car loses power is to run 2 cars with equal weight drivers in say a 2nd or 3rd gear pull. I bet the results will be pretty close. If anyone in the Fresno area has a stock car that would like to donate their time, I'm down to donate mine as well. Otherwise it'll probably be up to the SoCal members as your Z density is quite a bit higher

As I've said before, the aFe probably doesn't gain any power, but there's definitely not a huge loss in power either.

It definitely won't lose significant top end power, at least not in one freeway pull, the losses would likely show up at very low speeds like in traffic where the car is standing still and heatsoak can occur, or in lower RPM where you want more mid range torque.

The driveability are what keep me away from aftermarket intakes, the s54 has a tendency to die if you clutch it in from high rpm at high speeds... as well as the reduction in filtering ability and getting filter oil on the HFM.

It's just not worth the 5hp on the top end to me personally, I think overall the stock system is best... but best doesn't always be maximum HP or performance.

[Erhan]

Okay here is a short video. Recorded with HD Hero. Sound is recorded with Zoom H2. Windows are closed. Zoom H2 is sitting on the passenger seat. Didn't rev up to redline. Will do longer videos & comparison with stock some time.

[ga41]

That sounds very cool. How about a longer video now?

[Erhan]

I was at the Porsche club's (PCA) Driver's Skills event today. At least 5 people commented on how good the engine sounds

[Erhan]

And here is the longer video from the autox session of the PCA event.

[Eccentric]

any update on the stock vs Afe pulls?

[Panchio]

Originally Posted by pokeybritches

I agree, the stock intake is very good. But, the stock box has three filters vs. the AFe's single cone filter. I didn't notice a power gain or loss either way, but I'll let you know once the 110+ degree temps start setting in in a couple months. It seems to be a airflow vs. air temp argument.

Because of the vast improvement in sound, I'd say the AFe is one of the best bang-for-the-buck mods for an M. It made the car a lot more fun to drive, and it's only rowdy when your foot is to the floor (unlike an aftermarket exhaust). It really exaggerates that unique M gurgle/roar/wail/scream.

I ended up getting the AFE and you are right, it only makes the car sound great. I did not notice any performance gains...

[z4mduran]

I just installed my AFE this weekend... CAR SOUNDS WAY BETTER THAN STOCK.. i did notice better MPG.. and i did notice more pull on the freeway 50+ mph, i dont drive hard on the street

[babydevilj]

lmao my s/c M3 sees 9-12 mpg. my z4 sees about 26 mpg

[steveff4]

I did this mod purely for the intake sound. I track my car (HPDE) and I just flat out couldn't hear it at all, particularly if there were other cars nearby. Now at least I can hear the car rev when I'm on the throttle.

It doesn't hurt that most BMWs produce a fantastic intake sound.

[blender]

RE: aFe intake for Z4M

These are currently $397.99 plus shipping from VR Speed Factory (vr-speed.com)
part# 54-11521


Disclaimer: I am not affiliated with any vendor or reseller. But I CAN use the google.

[VinnieAces]

Originally Posted by rclem05

RE: aFe intake for Z4M

These are currently $397.99 plus shipping from VR Speed Factory (vr-speed.com)
part# 54-11521


Disclaimer: I am not affiliated with any vendor or reseller. But I CAN use the google.

wow only 397?? Is this standard or a sale price or somethin? seems like a good mod for this price