Standard (with cats) Cerb 4.5 db?

[athomp04]

I have searched with no joy unfortunately - can anyone please assist?
Thank you
Ashley

[julian64]

If you are talking at the standard 3/4 throttle used by race tracks in england then

4.5 standard back box and cats 95db

4.5 standard back box and linked decats 98db

4.5 straight through 103 and above.......way above some of them

[athomp04]

Thank you Julian

[Dave_M]

As above I suspect they vary a lot. I know meters vary a lot, but my V8S was 98 and is very, very quiet compared to the cerb (sports pipes and decatt).

[Byker28i]

I have lots of readings of mine, 1997 4.2, measured at 4000 revs, 0.5m from the tailpipe at 45 degree angle as was the requirement for trackdays. Now most ask for 4500 revs.

All were measured at Castle Coombe, verified again at Motorsport event trackdays in an open area, and again using our very accurate sound equipment at work.

All with standard TVR manifolds
When I got it - sports tail pipes plus cats 108db - no cats 116db
SP full exhaust system, no cats, sp crossover pipes 109db - with cats 100-101db
Standard backbox with cats 98db, without cats 108db, with SP crossover pipes (no cats) 108db
ACT quiet system, no cats (straight through pipes with no crossover) 106db, with cats 97db

With ACT stainless, tuned length manifolds
ACT quiet system, no cats (straight through pipes with no crossover) 108db, with cats 99db

ACT trackday cans cut between 8-10db off the noise level off all the systems above. I wouldn't imagine a 4.5 would be much different to a 4.2 in noise terms.

[vroom]

Dave_M said:

As above I suspect they vary a lot. I know meters vary a lot, but my V8S was 98 and is very, very quiet compared to the cerb (sports pipes and decatt).

Hi Dave,

I wondered what that smell was when I was trying to keep up with you a while back

It reminded me of my Dad's old Ford Cortina!

Nick

[Mr Cerbera]

Depends on what you want to know for....
If it's for circuit entry then I wouldn't bet on the figures taken by the circuit clerk matching up with theoretically (or real) posted figures.

I went to the Nordschelife a few years ago and had a fine morning there. When the traffic built up in the afternoon they pulled me over for a noise-level check and said that I had 108db ... and that was with the standard pipes, cats and backbox.

One hour later, when the traffic had died-down a little, I was let back on