Exhaust noise level?

[pb3]

Having done one year of on road motoring I am now about to book a couple of track days in the coming months. However, I have a slight concern about the noise output of my exhausts and thus would like to be prepared before being turned away from the track. I have the standard stainless exhaust system and a 530bhp AS engine, does anyone know what I could expect the db measurement to be (I know this varies over time but a ballpark figure would be useful)?

If the standard system fails the posted noise limit what do you do? Is it acceptable to improvise some form of sound deflection/redirection?

[canam-phil]

Why not nip over to Snetterton (as it is your nearest) on a trackday and they will test for you.

Mine is a 500bhp engine (not AS) that tests as 101 left hand and 105 right hand at Goodwood and they then consider the car as passing the static for a Goodwood day.

Driveby needs care

[B1 ECC]

Mine's 500+ and measures at 102/103 db, when last tested at Oulton Park. At Donnington i've never been pulled on the drive-by test which 98db.

>> Edited by B1 ECC on Monday 31st January 12:37

[BobM]

I went to Oulton Park with mine when it was relatively new. The limit was 105dB and although they let me out they did say 'could I get it a bit quieter when I come next time'.

[gtr-gaz]

I wonder if getting them ceramic coated would bring the db down a bit?

[mrloudly]

God this really pi..es me off!!!!

Boycott the tracks that whinge! They'll be putting bl..dy Gatsos on the main straights soon. It's a racetrack for Christs sake, what do they expect?....

[builder]

mrloudly said:

God this really pi..es me off!!!! Boycott the tracks that whinge! They'll be putting bl..dy Gatsos on the main straights soon. It's a racetrack for Christs sake, what do they expect?....

If it's anything like The States, it's not the track, but the neighbors that cause the issues...

Someone builds a sweet track (or airport) out in Bumfuq, Nowhere. Time passes and the land developers move ever closer - building homes as they pack'em in. The noise complaints increase (in direct proportion to the proximity) to the local government. Local government is pressured into legislating and enforcing db limits on the "offenders". Hell, at some airports here, pilots are fined $$$ for making too much noise. There are signs posted to "fly quietly". As if...

[mrloudly]

A lot of the circuits over here started as airfields. I wonder what's quieter B17 or GTR

[just dave]

mrloudly said:

A lot of the circuits over here started as airfields. I wonder what's quieter B17 or GTR

Hummmm.... G-man and (ex)Stig's v. B17.....

My money is on the B-17!!!

Dave

[omitchell]

just dave said:

mrloudly said: A lot of the circuits over here started as airfields. I wonder what's quieter B17 or GTR Hummmm.... G-man and (ex)Stig's v. B17..... My money is on the B-17!!! Dave

IIRC G-mans exhaust unpacked is ear bleedingly loud compared to 4 supercharged radial air cooled piston engines with straight through exhausts... it would be a close one with the engines on the plane kicking out around 130db each

[davefiddes]

I think it's a bit off when folk build houses or move next to a motor racing circuit thast has been there for decades (like Brands Hatch) then moan about the noise...I mean. Duh, what did you expect?

[pb3]

Conversely, I bet people who moved to Silverstone in the last year were worried for a while, assuming people there don’t moan about the noise.

But back to the point; what is the solution, for the car that is? I’ve seen one trackday company mention hiring extra silencing equipment from them if necessary and available, what would that be?

[Tam Lin]

pb3 said:

I’ve seen one trackday company mention hiring extra silencing equipment from them if necessary and available, what would that be?

Hi,

Different car (Cerbera 4.2), same problem. The extra silencing equipment in my case is a sleeved insert which fits into the exhaust end bore, and which reduces noise by up to 5 dB, at the loss of probably 15 or so ponies. Seems to work quite well, straps on with jubilee clips, I got mine second hand. What bore is the exhaust on your Ultima?

[steve_D]

Be carefull adding extra bits to the exhaust. Seem to remember someone burnt the body above the silencers as the extra pipes caused the standard silencer to overheat. Turned a yellow body orange.

Steve

[pb3]

I found something useful in a Summit Racing Equipment catalogue for exhaust noise reduction. They are stainless cone shaped inserts that can be placed after the header collector inside the exhaust system. See www.secureperformanceorder.com/dynatechstore/vortex.cfm for more.
Has anybody heard of these before? Are they effective?
They would cost about $100 for a twin pipe system, but worth it just not to wake people in the morning (providing they work sufficiently!)

[USCANAM]

This is what we used on our Cobra at one time
http://store.summitracing.com/default.asp?target=esearch.asp&N=110&Ntk=KeywordSearch&Ntt=exhaust+inserts&x=18&y=8
Would be easy to install on the Ultima. The closer to the engine they are installed, the better they work.
Jack