Readers poll Lets see if you know........
 

When listening to the wheering , whistleing, sound your engine makes do you know what the source of the sound is.

Today I found that my original thought was not actually correct.
I hope what I found is true otherwise something is wrong.

Does the sound come from the fan ? Or does it come from the timing chains spining ?

Kurt Williams

I had always hoped that noise is from the fan :eek:

Looks like knowbodys sure. 20+ LOOKERS and only 3 votes . This should be interesting and educational for some of us . But this poll is to find out what you think not what you know for sure.


Kurt Williams

I proudly voted for the fan. I hope I'm right....

Fans: people have said they noticed a difference when they changed fans. Since there is also a distint noice from the air cooled motor, it must be the fan. But then again, other cars have fans and don't make that sound.

Chain: Interesting. Although other cars have chain driven components, the Porsche motor does emit a unique sound. It's as identifiable as a blown motor (that is a motor with a blower.) And the Porsche does have all those chain ramps and tensioners to increase the noise level. So it could be the chain.

At this point I'll pretty much believe what you say. You could convince me of either one. That said, I voted for the fan b/c that's what I always thought.

Turbine sound? Do you know what a gas turbine sounds like? I've heard the "whine" of aircraft turbines, stationary power gas turbines and truck mounted high pressure frac pump turbines. None of them sound like a 911 engine. For one they're a hell of a lot louder plus the frequency is higher. Having said that, I would guess the characteristic 911 sound is actually a mixture of the fan noise, the exhaust note and timing gear drive train with additional interesting effects from the sound bouncing off the ground or close adjacent vertical surfaces. Cheers, Jim

Actually ... the term noise is inappropriate. Melody, music, or concerto seem more accurate!

I think you left off a couple of other choices ... c. Exhaust d. Both A & B e. Both A & C f. Both B & C g. ALL ! And, on that basis, I abstain from voting!

Without a recording made with one or more very expensive microphones ... and rather exotic spectral analysis and processing similar to that done in the movie <b><i>Sneakers,</b></i> a definitive answer is impossible! And, of course, individual ears and brains process the information differently and reach different conclusions!

I'm a fan Fan. ;)

HERE`S THE ANSWER TO THE POLL
 

Warren you didnt have to complicate it. You know what im talking about. Today I changed my 1.8 ratio fan pulley to a 1.3 ratio. When I was waiting for the correct belt to be delivered I started it up with out the belt and found that 90% - 100% of that familiar whining sound came from the chains. After putting on the belt the sound was identical to the sound without the belt. My chain sound may be particulerly loud because my chains gears tensioners(oil psi feed) and ramps are all under 500 miles. I love that sound and I am very happy it did not get quieter by slowing the fan speed. I did hovever notice a power increase at higher rpm`s.

Kurt Williams

No kidding, I always assumed that it was the fan.

Jim

'55 Speedster (gone but not forgotten)
'86 Carrera

Well, that would rule out the fan. But it doesn't mean the music comes from the chains.

Next remove your chains and see how it sounds ;)

perfect 911 sound recipe..
 

1 part transmission.

2 parts cooling fan.

2 parts intake.

3 parts timing chain.

3 parts exhaust.

Heat to 6000rpm, stir, and enjoy!

:D :D :D

Music? Hah!
 

I keep hearing this pap about "music" from the back.

Where could you possibly get the idea that it's music?

In my car, it sounds like I'm being chased by 6 oversize German rugby players after uttering some off-color remarks about their mothers' relationship(s) with various barnyard animals and how it directly relates to their genealogical provenance as evidenced by their less-than-savory countenance.

I always thought it was coming from my wife...