Standard v sleeved ehaust noise levels in db?

[Timja]

Has anyone measured the noise of their exhaust in db on a standard exhaust and on one that has solid rather than perforated pipes? Just wondered what the difference in noise in db is?

Also, what is the best way to measure the noise in db? I was thinking about using an iphone app for a rough idea but has anyone measured one accurately?

Do you measure 1m away at 45 degrees? how many revs?

Thanks

[str]

I had my exhaust sleeved a year or so ago and was delighted with the result -- both sets of cat remain in place and most importantly we have a little green sticker from TAG 11 which confirms db at 105 for RAC noise compliance purposes. But only just. The reading I think is at 75% max revs and the 45 deg is generally horizontal. Some tracks e.g.Castle Combe -- have lower max figure for track dy purposes so beware!

[Timja]

Thanks, don't suppose anyone knows what noise a standard exhaust produces?

[haircutmike]

My standard set up with precats removed has recorded figures from 96-98 DBs.

This is taken at 4500 rpm, 18" away from outlet at 45 degrees.

That was taken at a lot of different T/D venues.

I am currently running a standard exhaust with the main cat removed and it is HORRIBLE! Far too noisy, ok for a blat down to the pub but really annoying on a run.

My wife is addament she still heard it over a mile away on a quiet evening.

[lestershaw]

Mike,
When you say the main cat, I presume you mean from the y piece. If so do you think it would sound any better with a Clive f Decat ypiece or an act Decat y piece.
Reason I ask is that at the moment I have a straight through exhaust and my original catted y piece and it sounds great.
But I bought a clive f Decat y piece and I dont want to put that on an original silenced exhaust if it's going to sound rubbish

[speedtwelve]

My 400 has the standard exhaust with main and precats still in, and has been trackday noise-tested using the same criteria as HaircutMike describes at between 98 & 103dB.

[haircutmike]

lestershaw said:

Mike,
When you say the main cat, I presume you mean from the y piece. If so do you think it would sound any better with a Clive f Decat ypiece or an act Decat y piece.
Reason I ask is that at the moment I have a straight through exhaust and my original catted y piece and it sounds great.


But I bought a clive f Decat y piece and I dont want to put that on an original silenced exhaust if it's going to sound rubbish

I don't know how it would sound. All I know is that a decatted standard Y piece makes a standard system unbearabe for me.

I need to keep my sound levels within the limits for T/D's and the constant drone is annoying.
I'm no killjoy, it ks just not for me!