Acoustic Horn Surgery

[2kredz3]

Oh that horn! Nevermind, we do have it. However it's a part of the airbox as it's not clipped on.

cut it removal of that horn made more difference then cutting the horn that this post is about

[Ryan Mitchley]

Okay - well I performed the little snip this evening. The last time I had loosened everything correctly, but chickened out of the final heave-ho (I didn't know what was a good touch and what was a bad touch...)

I wasn't sure exactly what to expect. I didn't notice much low down, but there seemed to be a bit more up top - noticeable at around 5k and above. It felt like there was an actual bit of a powerband, instead of the usual linear freight train smooth rush to redline. Maybe the sound was a bit more demented up there, but it's not hugely different to stock.

[CaliAgents]

cut it removal of that horn made more difference then cutting the horn that this post is about

I just took a look at the other "horn" that sits after the filter and just before the MAF. It is removeable (secured by a T20 security screw). However, you can't just remove the horn itself without removing the plastic grid and mesh screen, which are imperative for smoothing out air flow before it reaches the MAF.

In actually that 'horn' is more akin to a velocity stack of you look at it again. I wouldn't mess with this one folks. Velocity stacks help draw in air at a greater rate of speed. Put that baby back!

[2kredz3]

I just took a look at the other "horn" that sits after the filter and just before the MAF. It is removeable (secured by a T20 security screw). However, you can't just remove the horn itself without removing the plastic grid and mesh screen, which are imperative for smoothing out air flow before it reaches the MAF.

In actually that 'horn' is more akin to a velocity stack of you look at it again. I wouldn't mess with this one folks. Velocity stacks help draw in air at a greater rate of speed. Put that baby back!

they must be built different, mine was causing a dirt to collect on once side of the filter and not the other telling me that i wasnt utilizing the whole filter in much the same way that the horn you cut in half was doing prefilter. no way mine is going back in prefer it much better with it out.

[Z3speed4me]

Well hes referring to an S54...
From what I looked at in pictures on realoem, they are a tad different in their intake design from both of ours.

[Nijapo]

I too have fiddled with pre and post filter horns. I ended up cracking the post-filter horn when removing and really wish I hadn't. It's shaped like a velocity stack, at least it was in mine and like Cali said it greatly helps with induction.

[willscam]

Constrictions in intakes and exhausts are not all bad. It depends upon their intent and design. I suspect the acoustic horns in the intake were engineered to take advantage of the Venturi effect. From what I've read, the S54 intakes are well designed and aftermarket CAIs haven't significantly improved upon them.

[Wojtek79]

So I did this last weekend. Louder engine, especially when you step on it. Engine feels better, but this could be a placebo effect.

[m090030]

I know I'm resurrecting a thread from 15 years ago.

Does anyone have a functioning link or saved document of Acoustic Horn ? I've been scheming for a while on how to improve the sound of my 2001 Z3M and this seems like something to try, but the link is broken and I can't seem to find details anywhere. "Cut the horn out of the box" seems to be the general guidance, but if there's a document with specifics I'd be remiss not to try to use it or read it.

[CPSmith]

If I remember correctly it’s just a little bit of plastic molded into the stock airbox that you cut out. Should be fairly obvious once you pull the air filter housing out of the car


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