To NOISY they tell me !!! 110db

[golfman]

Went to www.bedfordautodrome.com today. Whilst there they did a noise test on my Cerbera.

Guess what, it failed. Read 110db. 4500rpm approx 1m away. Limit for this track is 101db stationary and 87db when on the track at a certain distance away.

A bit of a pain in the ar$e as I recently had a set of cans fitted by Joolz, and was hoping this would be enough, obviously not! (anyone else had this done?)

Any suggestions other than pushing pillows up the tailpipes!

[joospeed]

the cans with the std box reduce it to under 100db .. dave haslam has that set up and his is about 98 db AFAIR. Obviously the sports rear boxes are louder than we think!

[atom290]

You have a fair amoun tof work to do there as that is 8 times louder than is permitted.

If your near Castle Combe they have some mufflers that might do the job, in the motorsport shop

[B19TOY]

joospeed said:

the cans with the std box reduce it to under 100db .. dave haslam has that set up and his is about 98 db AFAIR. Obviously the sports rear boxes are louder than we think!

As Joolz says with his intermediates fitted and a standard back box they measured mine on two separate days at Goodwood at 93db and 95db

[jj.]

Ooooh.. I remember this...
www.pistonheads.com/gassing/topic.asp?t=39909&f=18&h=0&hw=108db
Similar experience a couple of years ago.. read last post.
jj

[littlegearl]

i live 2 miles away from Bedford Autodrome and unfortuantly its surrounded by noise numpties...

yeah, on a totally clear day i can hear the sound of the cars, but tbh the squeeling of tyres travels further than the FPA cars... and all this is nothing compared to Santa Pod about 3 miles in the other direction!!!

trouble is, these numpties don't understand the jobs and the like Palmer is bringing to the area and just complain for the sake of it... they were so scared he was going to turn it into a racing circuit...

which clearly he wont and anyone who's been there could tell you that, and of couse he now owns 4 racing circuits!!!

[GCerbera]

golfman said:

Went to www.bedfordautodrome.com today. Whilst there they did a noise test on my Cerbera. Guess what, it failed. Read 110db. 4500rpm approx 1m away. Limit for this track is 101db stationary and 87db when on the track at a certain distance away.

I visited an event there last year and had a test done
just to see if I would be clear with my then 4.2 Cerbera.

Being loaded with sports pipes and decatted I thought
it was a long shot and when it hit 107db long before
the 4500rpm, he just shook his head.

What does concern me though is I know some people who
pass the static test and on their first flying lap
fail the drive by and get ejected...with no refund?!

It seems harsh to have to just write off the £200

Having looked at the calendar, there is only one 110db
event listed.

National Circuit, 110dB Donington Park Mon 1st Nov 2004

I now have a 4.5 Cerbera, still with Sports pipes
but no decat. A decent track day would be of interest to
myself and many Cerbera owners, but the db rules
may exclude many of us.

Any track day regulars got any thoughts other than
us all buying the ACT adaptors?

[M@H]

Johno had a complete muffler box/silencer with a single side exit to fit over both the pipes on his S Series.. quite a bit of weight to add to the back of an exhaust system I suppose, but it looked like it would work a treat.

Cheers,
Matt.

[dcw@pr]

have a look on the RMA website, www.rma-limited.com - they have half a dozen or so unrestricted noice days this year.

[roop]

What with the noise tests done at 1m and trackside, how about some adaptors that add onto the tailpipes and point them sideways and perhaps down a bit. One pipe to the left and one to the right. A direct measurement at 1m pointing at the back of the car will have neither pipe firing directly at the test meter let alone two. If they go to one side to measure the pipe firing at the meter then they will only have one tailpipe firing at the meter so they noise will be less as the other pipe is pointing directly away from the meter.

Roop

>> Edited by roop on Thursday 12th February 12:09

[roop]

I though dB's were logarithmic. Hence an additional 10dB's double the SPL. 110dB is therefore double 100dB.

[quote=atom290]You have a fair amoun tof work to do there as that is 8 times louder than is permitted.

[DustyC]

roop said:

What with the noise tests done at 1m and trackside, how about some adaptors that add onto the tailpipes and point them sideways and perhaps down a bit. One pipe to the left and one to the right. A direct measurement at 1m pointing at the back of the car will have neither pipe firing directly at the test meter let alone two. If they go to one side to measure the pipe firing at the meter then they will only have one tailpipe firing at the meter so they noise will be less as the other pipe is pointing directly away from the meter. Roop >> Edited by roop on Thursday 12th February 12:09

That sounds like a bloody smart idea and complies with some of shpubs threories on his website.
He suggests pointing them down I think.

[washy]

This is interesting. My standard exhaust equipped 4.5 RR Cerb runs about 107/108dB static at Bedford. Sounds horrible at 4500rpm with no load (the marshall said it sounded horrible and needed looking at. It's spot on though I've checked). Rather than send me home an instructor drove the car at full chat past a measuring point on the circuit and it came in at 83dB or thereabouts. A good bit under the required 87dB or whatever. All was fine for a handful of events there but right at the end of the season on a windy day I was black flagged and sent off!

My question/comment is this (Joolz may no the answer to this). If the Cerb has fuelling and ignition based on throttle position without load sensors does that cause the incredible racket it makes at 4500rpm static compared to the relative peace of 4500rpm under load i.e. is it noisy because fuel is burning in the cats at standstill not in the engine?

Washy

>> Edited by washy on Thursday 12th February 13:10

[[e-mail]]

Brands Hatch, Snetterton, Cadwell Park and all have trackdays booked by EVO, GoldTrack, RMA, BookaTrack, EasyTrack etc which run to 110db, measured at 1m and 3/4 revs... at Oulton Park trackdays for cars run at 105db measured at 0.5m at 3/4 revs.

All measurements are taken at 45 degrees up and out from the pipe, or in the middle if twin pipes...

hope this helps...

[Le TVR]

roop said:

I though dB's were logarithmic. Hence an additional 10dB's double the SPL. 110dB is therefore double 100dB.

It is logarithmic, but +3dB is double the SPL. +10dB is 10 times the level, +20dB is 100 times etc...

10 x log(Pa/Pb)

[steve lewis]

The noise issue is sadly going to get worse.
Goodwwod, Thruxton, Oulton, Beford all are surrounded by noise numpties as has been said.
Sadly we will have to comply.

The other issue is the timbre of the noise.
For some reason a Ferarri scream registers less on the db metre than a burbling Tiv.
Personally with a sports exhaust fitted I usually get away with the german handgrenade style inserts from (scream n squeeks) up the pipes.
Also the measuring devices can be slightly different at each circuit.
What I am not in favour of is the hypocricy.
I have been on circuit behind a Methanol powered Bugatti. My eyes were watering but my ears were in 7th heaven. I bet he was over the noise limit though.
Also it makes me laugh when aircraft and helicopters take off from the circuits. Now most of them are over the 101dba

Anyway.
It's going to get worse guys.
Sorry!

Best regs
Steve L

[2 sheds]

GCerbera said:

Any track day regulars got any thoughts other than us all buying the ACT adaptors?

Yes hire them ?

I think that people intending to attend track days should think twice before fitting sports exhausts though, as tail silencers of any type will have difficulty reducing the noise levels for the circuits with low limits.
Tim

[ehasler]

Hiring is a good idea - do you know where you can hire them from?

It's fair enough saying that people should be aware of this if they chose to buy sports exhausts for their own car, however some people will have bought used cars with sports pipes already fitted by a previous owner. They will then have the additional expense of either buying extra silencers or reverting back to a standard exhaust if they decide to take their car on track - quite expensive if they are not planning on doing (or can't afford to do) track days regularly.

It's even more expensive if you find out on the day that you're over the limit, as certain circuits won't give refunds if they send you home for being too noisy...

>> Edited by ehasler on Tuesday 17th February 20:43

[2 sheds]

I will hire them for £10+vat each, + carriage if required.
Tim

[GCerbera]

2 sheds said:

GCerbera said: Any track day regulars got any thoughts other than us all buying the ACT adaptors? Yes hire them ? I think that people intending to attend track days should think twice before fitting sports exhausts though, as tail silencers of any type will have difficulty reducing the noise levels for the circuits with low limits. Tim

Hi Tim

Sorry, didn't know we could hire them from you.

However, many Cerbera owners have sports exhausts.
What sort of db reduction could we expect based on
that if we use your silencers?