The Impreza Wub Wub sound.......?

[rjben]

Am I right in assuming that it is caused in entirety by the unequal length headers? I know that the firing order dictates that the exhaust passes through long header then short header, long header, short header and so on. Is there anything else that could influence the unique sound such as duration between cylinder ignition i.e. is it always an equal duration?

Regards,

Rob

[chuntington101]

you can get equal length headers and these kill the throb sound you get with the scooby flat four. also i think the turbo changes the sound.

thanks Chris.

[tank slapper]

As far as I know, it is entirely due to the length of the headers being unequal. If you hear one of the Spec-Cs they have equal length headers and have a different sound, similar to other 4 cylinder cars.

http://uk.youtube.com/watch?v=xzkypVhbR74
http://uk.youtube.com/watch?v=ZPPXZGmfS9c

[Mr2Mike]

You can make any 4 cylinder car sounds like an Impreza by pulling a plug lead off.Some call it the "Scooby warble", I think it sounds like a terminal misfire.

[rjben]

were gents, thanks for as the info!

[Zad]

Once someone points out that they sound not unlike VW Beetles, they never sound quite the same again

[bmwlad]

r5 turbos are the same with a nice exhaust on them the sound the same.

[Avocet]

I think all flat 4s sound a bit like that, Some of the Alfa engines were flat 4s and they sound much the same. Strangely, some V-Twins (particularly Harleys) have a similar sound at low revs too. I'm sure header lengths, turbos, cam profiles etc also have an affect but I believe the basic noise is just a function of cylinder configuration.

[skid-mark]

it's true its down to the unequal lenths of the headers/maifolds legacy has same engine as scooby but is quieter cause it has different exhaust/manifold lay out

[Tres_Bien]

Totally down to header length..the old Saab burble is cos of this.

[Tres_Bien]

Tres_Bien said:

Totally down to header length..the old Saab burble is cos of this too.