Noise levels

[Ozzy]

I've been reading some stuff regarding noise levels on track days. Seems that most circuits have a limit of anything between 98 to 105 db. My car has a bog standard exhaust. Measured this the other day as per recommendations. Held meter at 45 degrees from outlet, at 1/2 metre away, held revs at 5000 rpm. Meter reading 108/109 db. Do I have a problem participating?????????????????????????????

 

Still Shaking

[Irrelevant]

Yes - it's too loud

 

Accumulating bits for the Super-Busa. . .

[paulyb]

Depends on the venue.

You've no chance at Donny, Goodwood, Coombe and Bedford, but the Indy at Brands don't seem to test, ditto Silverstone and Cadwell.

 

Might be worth trying an alternative exhaust. My Raceco dropped my SLR from 106 to circa 100. With the airbox to I can just about squeeze below the drive-by and if I'm conservative with the revs 😬 😬 😬 below the 98 limit

[Ozzy]

Find this hard to comprehend! How can Caterham fit an exhaust that you can't use anywhere. Also cheeses me off, as the exhausts brand new. What's it going to cost to get one that complies?????????????????????

 

Still Shaking

[paulyb]

Ozzy

Yes - its pretty gutting really, but the aftermarket exhausts are better made, lighter and depending if you ditch the cat and increase the bore better breathing.

 

Loads of threads if you do a search but the Titanium Raceco is a lovely piece of kit.

Take a look here

[Stuart Faulds]

Ozzy, what spec engine do you have? 108db is very loud - are you sure the meter you're using is accurate? Oh, and I assume you're using it in an open area?

 

Edited by - Stuart Faulds on 3 Nov 2004 09:56:48

[Jason Plato]

either your exhaust silencer is knackered or your meter is duff

 

I ran with several differnt Caterham silencers - 5"& 6" and I never exceeded 98Db on the static test . Even with throttles and full 200bhp K .

 

Many others also run the std caterham silencers and they too are below 100db .

 

Dave

 

 

 

 

 

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[Shaun_E]

Noise measurement is a) a pretty inexact science and b) affected by many different things.

The surface and location you were testing on can have a big impact - e.g. a hard surface or confined space will increase the reading.

A noise meter is only accurate if calibrated. I tested my car using a proper calibrated noise meter and on my drive (tarmac) it recorded 100db at 5000rpm at 45deg and 1m. This is on a Superlight (1.6 supersport engine) with 4-1 competition exhaust witha 5inch silencer.

Each circuit will have a different noise meter and the conditions on the day will affect the reading so you might be lucky or you might not be. The circuits readings are also likely to be variable.

Drive by is probably a more accurate and consistent reading than a static test but of course is a bit more difficult to measure until it's too late ☹️

108/109db is seriously loud - that would indicate a virtually unsilenced Caterham so unless all the packing has been blown out of your exhaust this is not likely to be a true reading.

 

Yellow SL #32

[Ozzy]

Engine is 1600 supersport. I tested the reading on my drive, although this is surrounded by a garage, fencing, and hedges. Maybe I need to be out in the open? Noise meter is the usual cheapo mail order gadget (£40 I think it cost)

 

Still Shaking

[dino ferrana]

It must be reflection or a very dodgy meter! That car should be nowhere near that loud.

 

If it is on a standard exhaust (4-1 inside the body) I would expect it to be sub 100db.

[Gary Furst]

Ozzy,

 

The alternate method frequently used by racers is to lie about your max rev limit, the scrutineers generally don't know what the limit is for every car.

[Stuart Faulds]

A 1600 supersport on a standard exhaust should be around 96db, slightly higher if it's the 'competition' exhaust without the cat.

[GTD]

Goodwood measured my car with exactly the same exhaust and engine as yours at 103 dbs static. As others have said, it is very variable - another major variant is engine temperature. Did you start up from cold and measure, 'cos if so try again after a 20 minutes drive to get things warmed up.

 

G 4 Geoff

Leather Good - Carbon Fibre Bad

619 GTD here

[Tony Martyr]

Highly suspect reading.

Sugest either:

additive refection at point of measurement

incorrect weighing setting of the meter

directional mic fitted to meter

meter out of calibration.

all any permutation of all 4

[Nick Green]

Also, IME, 5000 rpm is quite a high rev point to test at.

 

4000 or 4500 is more usual on track days. 500 revs can make quite a difference in that sort of area.

 

Sprints tend to have 105 or 110 dBA limits.

[old captain slow]

My 1600 K SS with competition Caterham exhaust comes in at around 96dBA at 4500 measured several times at Combe. I think you would be hard pressed to get 108dBA even without the silencer. Suggest you get the jobby calibrated - sounds wrong.

 

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[Archie Procter]

Agree with all the above, this figure would represent a massive noise and would be seriously upsetting your neighbours. Even before the RaceCo my 2.0VX only measured around 101dba and that exhaust had seen better days!

 

Why don't you take it to a trackday at your nearest circuit - there are plenty of weekend ones on at the moment - and get it noise tested there. Then you can either get in touch with Ammo or send the noise meter back demanding a refund.

 

Andrew

[AMMO]

My Crossflow with knackered 5" silencer measured 109 dB at 0.5 metres. Matt Deakin's Blackbird measured 116 dB (ouch). I think the the high figures quoted are believeable. Unless the noise meter I use for silencer testing is knackered too! I doubt it though.

 

AMMO