Exhaust Howl

[johnz3]

Can someone please explain what make the exhaust howl noise that you hear from a car.

As an example before I brought my 3.0i Sport I tried a Boxster S and the exhaust really howled when he accelerated hard.

[Mugs]

for a start they are different engines....the porsche has a 6 cylinder boxer so it sounds different but i believe it is mostly down to the exhaust and how it is tuned (silencer / resonator etc).
i do a bit of motorsport and even some of the 1ltr micras in the events have a nice howl and all they have done is fitted an exhaust and filter.
a custom system should get the desired sound.
i'm someone who knows more about the subject will be along soon

[pedro20001]

My 2.2 manual really does growl and pops on the overrun and it's on a standard exhaust!

[Davejue1]

I have a stainless steel exhaust on my 2.8 and it gurgles on the overrun and sounds great when it's given a bit of harder driving. So I'd say a combination of 6 Cylinders and a decent exhaust system makes for beautiful music!

[Woody1000]

I spent ages listening to exhaust notes prior to buying my exhaust and my view is it's down to the rear back box, some are made of thin metal and make a tinny sound, mine is a Eisennman exhaust and makes this type of growl !
http://youtu.be/7TzQPyzdhss

[Del]

I suspect the OEM Z3 exhausts are built to be conservative and quiet. They are very heavy. Stainless steel exhausts are made from much thinner, lighter material and so more exhaust noise escapes. I have a custom, stainless steel exhaust from Longlife on my 1.9 which was their quietest option but it makes a much more sportier growl than the OEM one. The noise is so different that people have asked me what engine the car has in it and whether any modifications have been made

[Southernboy]

.......... you want to hear a howl.... give it horns mate !!.... and if you have a Simota air intake fitted, it will add a seriously throaty roar to the symphony...

[Zed Free]

The OEM exhaust on my 2.2 sport appears to be stainless, it is not magnetic, is nice and shiny and like Pedro20001's 2.2 it makes a lovely sound and pops on over run.

Not sure if this was something that they put on the sport models as standard as it is not listed in the extras on the vin decoder web site.

I can't wait til tomorrow when my tax starts and I can drive it again and make those lovely noises from that smoooooth 6cyls.

[Mike Fishwick]

What is so good about an exhaust which pops on the overrun? It is usually a sign of an exhaust leak!

Popping? Howling? Gurgling? Some people have very odd ideas about pleasant exhaust notes . . .

[BladeRunner919]

What is so good about an exhaust which pops on the overrun? It is usually a sign of an exhaust leak!

Popping? Howling? Gurgling? Some people have very odd ideas about pleasant exhaust notes . . .

Different people like different things.

[Davejue1]

Absolutely right bladerunner!

[Vic-Z3]

Pop on kitty .................

[Zed Free]

Sorry, didn't really answer the original question.

There are many factors that make up the different sounds between cars. For instance taking a six cyl engine you can combine them straight into one pipe with a log style exhaust manifold or you can combine it into two lots of three cylinders or three lots of two cylinders. You can vary the lengths before they combine which tunes the pulses to help scavenging the exhaust from the other cylinders. You then have the choice of running a single pipe from front to back which I believe is what is done on the earlier zeds or you keep two separate pipes with three cylinders into each and then just pass them through the same rear box as done on the 2.2 and 3.0 I believe.

That is before you consider the size of each silencer or the effect of different cam timings.
As you can see there is a lot that can be changed and will give different sounds.

[Koolflyer]

Keep popping baby.............