Why does my 2.8 z3 sound bad?

mjacob23

Newbie
Joined
May 2, 2022
Points
3
About a year ago I purchased a 50k mi. 1999 2.8 z3 roadster (5-speed) and I love almost everything about the car except for the sound. It really just sounds like a big vacuum cleaner until you get past 4k RPM and you can barely start to hear the engine but even then it sounds meh. I don't want it to be unnecessarily loud, but being the car it is I do think it should sound better. Is there anything I can do to hear the engine more to eliminate the sound I'm hearing?
 

Mike Fishwick

Zorg Legend
French Zeds
Joined
Sep 23, 2021
Points
76
Location
Daglan, France
Model of Z
2.8 Roadster
It depends on what you mean by 'better!'

As usual, we are not told any useful details -do you have an M52 tu engine? In this case the RH exhaust outlet has a flap valve which is normally closed to reduce exhaust noise, which opens at about 3500 to 4000 rpm. Exhaust noise therefore increases from this point.

The usual exhaust note is a bit of a drone, and things are not much different above this point - but why people want more noise I cannot imagine - except to hopefully make an impression on bystanders.

The only really nice sounding Z3 models are the 2.2 and 3 litre types, which use seperate pipes and front silencers for each 3 cylinder group. These sound like a reaL 'six' in the way that an old Jaguar XK 150 did.

If you want noise, have the front silencers removed, or buy an after-market rear silencer such as Eisenmann, which is lovely in small doses and when passing through a tunnel, but is a real pain on long runs. I used to wear earplugs, and eventually had a custom-made exhaust system built, which is ultra-quiet, like a 328 saloon. As someone once remarked, noisy exhausts are for the deaf or the immature . . .
 
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Scooblitz

Zorg Guru (III)
Supporter
British Zeds
Scottish Zeds
Joined
Aug 7, 2017
Points
135
Location
Glasgow, Scotland
Model of Z
2.8
About a year ago I purchased a 50k mi. 1999 2.8 z3 roadster (5-speed) and I love almost everything about the car except for the sound. It really just sounds like a big vacuum cleaner until you get past 4k RPM and you can barely start to hear the engine but even then it sounds meh. I don't want it to be unnecessarily loud, but being the car it is I do think it should sound better. Is there anything I can do to hear the engine more to eliminate the sound I'm hearing?
I suspect that what you are hearing is actually the viscous coupling fan stuck in a locked position?

This is very common. Mine has this issue but is now half remedied with a new viscous coupling unit.

The viscous coupling or clutch is spun by the engine as part of the front serpentine belt assembly.
When these viscous couplings go bad, they often match the engine speed of the car, creating a big whooshing sound like a bus as the revs increase.
Usually, the viscous couplings are limited to spin at 3000rpm but if broken could even spin to 7k! This would be very bad. Very bad indeed. Potential catastrophic engine damage.

I ran my car without a viscous coupling and fan for a year or so. Airflow into the engine is sufficient to keep the engine at temperature.
Long traffic jams/accidents would be the only danger to doing this as the car has no fan cooling and could overheat.

When idling, is the fan spinning quickly?

If the viscous clutch is not the culprit and just an undramatic sounding car, a rear middle box resonator delete is a cheap and easy way to make it purr a little deeper.
 
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