964rh

Your confused?!?!?

My local track (Donnington) has a fairly strict noise ruling for the cars, but is situated directly under the flight path of my local international airport. I believe it's about 1/2 mile from the end of one of the runways.

Rob

aeroman

Well not to be a puff or anything, but you UK people are very millitent about noise. LHR is the tent pole airport for aircraft noise restrictions in the world.

I would like to see a copy of the regs for the track out of curiousity. You have a link?

964rh

No sorry, try a quick google search for donnington circuit.

Rob

911addict

I know that turbos are supposed to be quieter, but on Saturday, my friend tested my car, at 50cm and 45 degree at 4000 revs and it read........ wait for it................ 109!!!

Re-tested it again with a tape measure and it read a much more reasonable 91 at idle, and 104 at 4000. Now I can go tracking.....

boxsey911

You've hit the nail squarely on the head there Aeroman. But please don't confuse us proud UK 964 owners (and other high performance car enthusiasts) with the righteous (poorly informed) lot that are turning our country into a shadow of the empire that it used to be. What with the ever increasing anti sports car attitude by pressure groups and the government, you would hate it over here.

We're fighting a losing a battle. One circuit (Bruntingthorpe) has already lost the right to let us use it for trackdays. In years to come I'll bet we will be reduced to looking at but not starting our Porsches . But in the mean time, even if we have to soften their noise a little we're going to make hay while the sun shines!

SimonExtreme

This is a real issue in the UK and it is all too easy to be very blinkered about the situation, only looking at it from tghe viewpoint of wanting to run our cars.

The UK is a small island witha large population. Circuits are, generally, in areas where other people want to indulge in other activities, be it the peaceful enjoyment of their homes or rambling in the countryside etc.

We, as motoring enthusiasts, are very unsympatheic to the issues. We (964 owners) wouldn't be have anything to complain about if we stuck to standard exhausts. The noise levels would then be OK. So who is in the wrong? The people who want us to be quieter in our sport or the people who run noiser exhausts than they need to.

A little give and take is what is needed. Otherwise, do what I have done and move somewhere that has circuits away from people, where there is enough space that everybody can do what they want without upsetting each other.

(BTW, I run a big loud exhaust system )

aeroman

It says 98 dba but nothing about at what distance on the donnington circuit webpage.

SimonExtreme

98db is a strange figure. If that is static, then no 964 will make it. If it is drive by, then it is high and you will get through without problem. Having driven at Donnington, I had thought it was a drive by test but it wasn't in a Porsche and noise wasn't an issue in the car I had.

As I think I have said, if it is a static test then it will be at 0.5m and at 45 degrees. I cannot remember any circuit doing staic tests differently.

FWIW, if it is a drive by test, make sure you know where the noise meter is and pass it while as close to the other side of the track as possible. In addition, short shift so that you aren't at full revs.

74carreraturbo

how does the car sound with the cat bypass/cup pipe? Is it overly loud for street use?? Do you get the usual smells that come with removing the cat??

Superunknown

It sounds loud! Not too overly loud though, just right ! No smells with regards to removing the cat imo

TR6

We are fairly lucky here in north Texas. At Motorsport Ranch and the new soon-to-open Eagle's Canyon, the only locals we bother with noise are the cattle for the most part.

boxsey911

I'm booked at Donnington in July which is one of the reasons I've just taken off the G pipe and put on a standard final silencer. I was reliably informed that the 98 dba limit is a drive-by measurement. This is backed up by the following webpage on their own Trackday company website:

http://www.donington-park.co.uk/circuit/noise.asp

On here they say that they will only pull you in for a static test if the circuit noise meters are exceeded. If this is all true, then some more noisy exhausts might make it on track there.

By coincedence I've just read a line in the PCGB mag (on the trackday page) that specifically warns that "964 models may not pass the noise testing on some circuits". Are we really the noisiest of the noisiest?

aeroman

98 dbA is way high and must be close. A good compass would be a 747 on approach measures just over 90 dBa at 394 ft from mic (in this case overhead altitude). I cannot see how my 964 would be making that kind of noise. Be fun though

SimonExtreme

aeroman

The noise meter is next to the track so we are talking about 30ft, not 300!

98db on drive by shouldn't give too many problems.

aeroman

Thats exactly what I was saying Simon. To get 98 dBa one would have to put the mic right in front of the exhaust. If you understand distance doubling and noise you should understand why.