Loud Exhaust M5 Cold Start

[playNskillz]

Hi guys, quick question how do I get a constant loud exhaust note the same as it is on a cold start? But constantly. I read somewhere it can be done. So its continuoiusly like that?

[JMBMWM5]

Wire open the exhaust valves, simple.

[Wills2]

I'm not so sure it's as simple as that the cold start is a pre programmed procedure that quietens down by design so I'm not sure what the valves been wired open will do.

It's the same with an aftermarket exhaust on as well there is always the cold start and then the sound settles down whether it has valves or not.

[AW10]

I think that sound comes from the secondary air injection that helps the cats warm up. Not sure that's achievable or clever all of the time.

[bennyboysvuk]

On the M135i, it's alleged that it is due to the wastegate being open during a cold start so the exhaust gasses and noise go straight down the exhaust and are not damped out by the turbo. I'd expect it's the same for the M5, M3 and M4.

I agree, it's when the exhaust note sounds at its best. I'm basically mourning the disappearance of the NA engine.

[Wills2]

After doing a little googling it appears the valves are closed during the cold start but open for the rest of the time.

[JMBMWM5]

Wills2 said:

After doing a little googling it appears the valves are closed during the cold start but open for the rest of the time.

NOPE they are not.
I have wired both my LCI M5 valves and my M6GC CP, both cars sound considerably better ALL the time.
The Valves even in Sport+ only open at the higher end of the rev band.

[paulmc]

I had mine wired open. Makes a difference. I undid it though as the extra drone annoyed me.

[AW10]

bennyboysvuk said:

I'm basically mourning the disappearance of the NA engine.

Turbos are great for improving fuel economy and reducing emissions but they act as sort of a blender/silencer taking out most of individual intake and exhaust pulses that make an NA engine at high revs/load sound so wonderful and leaving mostly nondescript "noise" behind. Not much that can be done about it.

[joscal]

I've wired mine open with the CP exhaust and absolutely love it, can't really understand the drone comment as mine doesn't?

Sounds like it should to me, it's loud but not obnoxious.

[paulmc]

it annoyed me around town. I think because the car was so refined it just removed that slightly. My GTR R35 has a crazy loud exhaust but that's what its supposed to sound like. Different cars, different expectations I guess

[hertfordshire1]

I also wired my valves open and then un-wired them as I found the drone annoying too.

It probably wouldn't have bothered me too much if I never had any passengers, but with the other half and 2 kids in the back, I found the noise annoying rather than pleasant.

I used to run an AMG Merc with an X-Pipe fitted and that sounded like Satan - So don't mind noise - but it has to be the right kind of noise...

Its very easy to to - so anyone thinking about it, should just do it and see if it suits them,

Cheers

Steve

[JMBMWM5]

joscal said:

I've wired mine open with the CP exhaust and absolutely love it, can't really understand the drone comment as mine doesn't?

Sounds like it should to me, it's loud but not obnoxious.

Mine never droned at all?.

[joscal]

Good points I'm almost always on my own so doesn't bother me but do know what you mean.

I had a tubi on my E39 M5 and hated it, was brilliant when in the mood but was embarrassing 99% of the time. Then an eisenmann on my E60 M5 which stayed on for a week for the same reason.

[bennyboysvuk]

AW10 said:

bennyboysvuk said:

I'm basically mourning the disappearance of the NA engine.

Turbos are great for improving fuel economy and reducing emissions but they act as sort of a blender/silencer taking out most of individual intake and exhaust pulses that make an NA engine at high revs/load sound so wonderful and leaving mostly nondescript "noise" behind. Not much that can be done about it.

I completely agree with all of that, not to mention that the throttle response is poor compared to a good NA engine too. Thus, IMO, turbos are fine for pottering about, but for pushing the car a bit harder nothing beats a good NA engine.

[Artey]

AW10 said:

Not much that can be done about it.

I present to you the electric turbo.

http://www.autoexpress.co.uk/audi/rs4/92266/new-au...

[playNskillz]

How can it be weird open? Is it something that can be done yourself or do you need to get it done?

[paulmc]

5 min job with a bit or wire, very easy.

[AW10]

Artey said:

I present to you the electric turbo.

http://www.autoexpress.co.uk/audi/rs4/92266/new-au...

But note it's only to fill the gap until a conventional turbo is up to pressure...

[Artey]

AW10 said:

Artey said:

I present to you the electric turbo.

http://www.autoexpress.co.uk/audi/rs4/92266/new-au...

But note it's only to fill the gap until a conventional turbo is up to pressure...

...at the moment

This technology is in its infancy and requires some structural changes to how cars are designed (we need to step up to 48V instead of 12V) but it will one day replace gas turbochargers no doubt about it.