Howdy.

Plan to participate in a trackday session where noise level is
restricted to 90dB. Will my MY00 with removed resonator, KN panel,
mild steel big bore decatted DP, decatted/desilenced Magnex centre,
and 6x4 Magnex BB go through??
Any opinions/exprience? What about other systems, e.g. full decatted Scoobysport (which I would guess is noisier)?

Simen.

 

OK, I'll re-phrase the question:
Anyone measured their fully decatted exahust system
with regards to noise?


Simen.

 

MY UK94 with a Mongoose SS (decat) was something like 93 or 94 DB using the RAC MSA regs which are 0.5 metre from exhaust at 45 degrees when revved to 2/3 max revs.

It wasn't too bad on the road, just a little droning on the motorway but I put up with it for the wonder flat 4 sound.

To put it in to some perspective, my 205 Sprint car ran a Group A exhaust (until I got advised it was too noisey) it was 108Db at the same event. On the road it was horrendous. You needed practice headsets on the motorway otherwise you'd hurt your hearing at anything over 60MPH.

Cheers

 

At what revs and at what distance does it have to be 90 dbi?

On the Sunseeker my car was reading 94 DBI @ 4K rpm with no cat and only running one box if this is any indication.

 

THIS LOUD!!!


Iain

As the others have said it's quite hard to tell, a road drill is about 100dB i think, so it's quieter than that.

 

British GT Marcos Mantis (GTO) is about 126.9 dB at approx. 4500rpm indoors, on a rolling road, measured at 5 metres.

To hear how loud that is, download this video, and play it at the maximum volume your PC can play it at. That will be about 1/4 of what it really is

http://www.powerstation.org.uk/Resou..._Rollers_2.mpg

Cheers

Ian

 

Blackscooby - I think your figures indicate that my setup might
be touching the limits, but the non stainless DP might keep it on the 'correct' side ..... Does the Mongoose have a resonator on the midpipe? (BTW you also have a 5dr, right? ;-) )


My system was turbo back, hence included a SS downpipe.
From my recollection it had 2 silencers (whats a resonator ?)
One rear and a small mid one. Both of which were straight through jobbies you could stick a brush handle

No mine was a 4dr.

Sold just before christmas


http://members.aol.com/blackscooby25...lackscooby.jpg

 

SSE,

FWIW, 90 dBA is quite a conservative limit.

My car makes about 102 dBA (Scoobysport backbox)

To put it in perspective ... in a cinema (with Dolby Surround) you will experience about 85 dbA peaks...

A dB meter costs next to nothing (30 quid ?) ... get one and measure yourself. One meter, 45°s as has been said before.
If needed, you can buy a "bung" that you can screw into your tailpipe, which will quiten it down enough to have no problem on track.

Being blackflagged on track because of noise limits really sucks.

Theo

PS: if you have or foresee to buy a home cinema ... you can use the dB meter to calibrate your system...

 

Theo,

Thanx m8 !
You actually reminded me we have a dB meter at the office

Alzheimer.

 

No Mantis GTO's are gonna cause trouble for us Scooby drivers on that trackday then....

Thanks for the replies.
Blackscooby - I think your figures indicate that my setup might
be touching the limits, but the non stainless DP might keep it on the 'correct' side ..... Does the Mongoose have a resonator on the midpipe? (BTW you also have a 5dr, right? ;-) )

Simen.

[Edited by SSE - 3/8/2002 2:55:41 PM]

 

Oh - sorry, think I confused you with 'Blackbeast' which is 5dr....
But nice car and piccie for sure!

Anyway, resonator = sound trap, guess silencer may be the more appropriate word... I think the mid silencer usually also doubles as an expansion chamber to deny you/us the pleasure of seeing flames in the rearview mirror

But the Magnex mid which is going on my car is a straight through no-nonsense cat and silencer free thing

Simen.

[Edited by SSE - 3/8/2002 5:27:40 PM]