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Discussion Starter #1
I own an E39 M5 Silverstone, with Remus Exhaust installed (special exhaust for the new M5, but not really louder than stock).
I tested many other sports cars (Ferrari, Maserati, Lamborghini, Porsche...) and, of course I know the M5 is not exactly the same type of car, I must say I'm really disappointed of the M5 sound at idle (500 rpm).

Did you try to stop at a silent place, get out of your car and listen to it ? Close your eyes and you'll think you own a 525 td..
No, really, this sound is NOT a sound of a 80K USD car.

I asked to some tuners here how to improve this sound at idle and they all told me that it would require a muffler change or sth like that, so this is not a problem of exhaust.

Did anyone here try to change mufflers or modify them, to have a pleasant constant sound of the engine ? For example Porsche aren't loud at all at idle, but they just make the right sound of a powerful engine, that's important.

I need to change that ! Even my 328 E46 i owned did a better sound..
 

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Discussion Starter #2
And could please some non-stock exhausts owners post sound at idle ?
I'd like to know if some exhaust performs enough to change the sound at idle.

BTW, a good sound at idle would hide perfectly the famous diesel knocking sound !
 

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Hi Tom,
the only way to get more "grumbling" sound at idle is to exchange the exhaust manifold.
The low diameter throttle the sound between
500-1000rpm.
I like the normal sound and the big V8-sound
from my car that begins from 1500rpm.
By the way: It´s a pity to stay with the car;
M5 is born to drive.
Tony
 

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Tom

I agree that the sound an M-car makes at idle is not pleasent, but trust me you do not have a truck engine in your 80k car.
Your motor is all car, fast car, even if it ends up in an X5 someday it will still be a car engine.

However, your transmission would do a fine job if you transplated it into a F-350 powerstroke and used it to tow your 745i to the repair shop again.

The noise you hear is the massive cogs in your tranny rattling around when the trans is in nuetral and the clutch is out at idle.
Like when you are standing outside the car.
Notice that if you push the clutch in the trans noise will go away in a couple of seconds. If the car is in gear with the clutch in there is no noise.

Anyone who has seen one of these trannys apart will agree M stands for massive. The
V8 engine even with all this stuff on it does not deliver smooth, continuos, unidirectional torque at only 8 revolutions
per second and this sets up oscillations in the trans which is what you hear.

The thrust bearings on the crank can also rattle a little at idle for the same reason but that noise is pretty subtle and you need to be under the car to hear it.

I don't think anyone is going to believe that 524td badge you are thinking of putting on your car.
 

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Tom...
I don't want to be insulting, but the sound of the engine in my M5 is sweet sweet music...and anybody thinking otherwise lacks the knowledge of what it takes to give you so much power throughout the entire range...do you have any idea how sophisticated the technology is in this engine Tom? Start with the 4 cams that adjust the lift automatically based on demands...do you know what lift is Tom? It's what gives you that wonderful "diesel knocking sound"...and enough torque to pull the Queen Mary into dock..Being an old gear head, we would put huge cam shafts in our chevys and fords, and barely get them to idle...this engine gives you more than that kind of performance, yet purrs like a lion at idle, and is balanced enough for the stop and go traffic most of us face... in my humble opinion..THIS ENGINE IS A MASTERPIECE...respect it and learn what it takes to give you this kind of horsepower...When BMW was planning this car, there was some thought to only offer it to previous M owners because of the sophistication and power it has,and the respect it demands from its owners...please learn about this car before you post uniformed opinions about it..and as far as the price...I believe the M5 is underpriced...I cant say enough about the machine you have in your control, and would gladly debate it with anyone, with facts ! If you want silence at idle, may I suggest you trade in your M5,(and get more than what you paid I'm sure) and buy a nice quiet Japanese Cruiser...and when some dude in an M5 blows your doors, remember what you gave up...
respectfully,
Bob
 

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Stanley-Bob

Despite your desire, you have been insulting
toward Tom for his apparent lack of knowledge
of the finer details of his M5. Apparently Tom and all of us should be warned that technical discussion of sophisticated equipment like this should be limited to individuals such as yourself who have an
in-depth understanding of these details.

Stanley-bob says;
"Start with the 4 cams that adjust the lift automatically based on demands...do you know what lift is Tom? It's what gives you that wonderful "diesel knocking sound"..."


Are those the same four cams that are opening the valves at up to 58 times per second ?
Do you know what lift is ?

The BMW VANOS system does not adjust valve lift! It adjusts the valve timing based on engine RPM primarily and load secondarily.

Do you know what cam timing is ?

It's what you old gear heads got wrong when you put your huge cams in your chevys and they barely idled, most likely because you were so busy talking about your lift that you didn't even check, let alone properly set, the cam timing and then blamed the resulting bad idle on the cam manufacturer.

If I may quote you

"THIS ENGINE IS A MASTERPIECE...respect it and learn what it takes to give you this kind of horsepower...When BMW was planning this car, there was some thought to only offer it to previous M owners because of the sophistication and power it has,and the respect it demands from its owners...please learn about this car before you post uniformed opinions about it..


Couldn't have said it better myself!!!
 

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Discussion Starter #7
I'm sorry to hear all that, I think you've missunderstood what i meant.

I believe absolutely that this engine is a great masterpiece, probably even more than Ferraris or Porsches engines.

Everytime I drive it I can't believe how powerful it is, during all the rpm range.

I like so much how it can push so much at 2000 rpm, no Ferrari or Porsche can do that.

BUT THAT WAS NOT MY TOPIC !
I was just wondering how M engineers, so attached to details and perfection, let the M5 have almost no-sound at idle..
At least if they managed to avoid knocking sound, I would understand that they wanted the car with NO noise at all.
But such knocking sound is not acceptable at this level, a 400 HP car has to deliver great sound, even at idle (my opinion).

BTW, thanks for some infos, I'll enquire about manifold mods.
 

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Discussion Starter #8
BTW, I think that nobody having paid 80K USD for a car should have to say that :

"I agree that the sound an M-car makes at idle is not pleasent, "

(RFS, previous message)
 

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Tom,
If you really want to make the M5 sounds like a race care at idle you can take out the cat from the car....but it will not pass emmision....& not street legal...


Just my $.02...

alpwhiteM5
 

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Tom...
first let me apologize for misunderstanding and overracting to your post...I know any of us lucky enough to own this car, cant help but love it...I just happen to enjoy hearing the mechanical sounds this car generates...
second to RFS...I want to thank you for your humbling response...yes i understand how the cam timing works, just didnt express it anywhere near as well as you did...we learn best from our mistakes, especially ones that embarress us...and hey RFS,where were you when I couldn't get the chevy II to idle ?
all the best from chicago, where premium is a lovely 2.56 a gallon...happy trails
 

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Tom
If I read you right you find the trans noise at idle unpleasent and would like to cover it up with a cool exhaust note by installing a new muffler.

I do not have any direct E39 M5 exhaust experiences to relate, but I was involved in an extensive test on an E39 540i6.

We removed the exhaust in stages, with a sawzall, testing for noise and power on a dyno at each cut, stopping just after the cat. We were making a smog legal exhaust.
The car was very quite at idle even with everything after the cat removed. Sveilside
is right you will probably not get any significant increase in volume at idle without removing the cats.

To stanley, glad to be of service. If your getting a noise at idle that is coming from
under the valve covers perhaps the lifters are acting up. Does it happen after hard runs, does it go away after you idle a while ?? Are you hearing the tranny noise I am refering to ?

If I might quote Tom Petty this time;

"It's just the normal noises in here"
 

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Andrew

Is your noise the VANOS noise others are talking about??

VANOS

Very Annoying Nasty Offensive Sound
 
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