Discussion
I just used our work sound meter to measure the Chim. I did it at 4.5k rpm ( engine was not up to temp.... ouch ) 45deg and 1/2 m away from left pipe.
There are no cats in the exhaust and a modified sports 'Y' piece joining the manifolds.
It measured 118db with a tickover of 105db.
Does this sound feasable ? ( sorry about the pun .. )
If so, is it legal on the road?
With those levels, am i defo gonna need some noise reduction baffles at a track? I dont want to arrive and then be told the computer says no.
There are no cats in the exhaust and a modified sports 'Y' piece joining the manifolds.
It measured 118db with a tickover of 105db.
Does this sound feasable ? ( sorry about the pun .. )
If so, is it legal on the road?
With those levels, am i defo gonna need some noise reduction baffles at a track? I dont want to arrive and then be told the computer says no.
A standard Chimera recorded exactly 100db at a track day I attended. Is your car that much noiser than chims? Also 105DB at tickover is very hard to believe. Are you testing it in a wide open space? You need to to get an accurate reading. If you are, it may be that your meter is not very accurate. Alternatively you may just have a b****y loud car!
Yeh - i thought it was too high. Looking at wiki though, 100db would be about as loud as a disco. I think if my ear was 50cm from my exhaust pipe even at idle, a disco would be a reasonable comparison.
110db would be a chainsaw at 1m. Or an accelerating motorcycle at 5 m. Not in the realms of loonacy that a 5l v8 with a sports 'zorst would be up there.
110db would be a chainsaw at 1m. Or an accelerating motorcycle at 5 m. Not in the realms of loonacy that a 5l v8 with a sports 'zorst would be up there.
To get this in perspective, I think my Westy is pretty loud with a 20XE engine and a 2.5" straight through exhaust and it measures 98db at 4500 rpm. 105db is much much louder than that, and I find it very hard to believe that your car makes that much of a racket at tickover (unless it ticks over at 4000 rpm). It might be an idea to pop along to your local track and get it sound tested by them, just to confirm your readings.
Noise meters generally have two smoothing and two frequency response settings. Are you sure you were using the correct ones? (Not that I know offhand which settings the MSA and so on use.)
My bog-standard Chim 450 usually measures 96dB or thereabouts everywhere except at North Weald this year where the bloke's meter must have been bonkers because he measured mine at 102dB and everyone elses were higher than normal, too.
My bog-standard Chim 450 usually measures 96dB or thereabouts everywhere except at North Weald this year where the bloke's meter must have been bonkers because he measured mine at 102dB and everyone elses were higher than normal, too.
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