Exhaust sound levels
Discussion
Part one: the before.
Having accepted that my car is probably too loud for the majority of the population, I have decided to get my car some silencing
Currently it has an ACT Supersports (straight-through), with ACT decat Y, no precats.
Just been playing with a sound meter to get some sound level measurements before the new exhaust goes on ......
With the meter 0.5m at 45 deg from the tailpipe ....
On idle 105 db
at 3000 rpm, 114 db
at 4000 rpm, 119 db
Not that I would want to, but pretty sure there's no track in the UK that would have me
To get some readings from inside the car I wedged the sound meter between the headrest and seat then took some measurments on the road, the meter is roughly "ear level".
Roof panel off, targa up, average readings
At idle, 90 db
30 mph in 5th, 95 db
under acceleration in 3rd up to approx 5000 rpm, peaked at 108 db
70 mph cruise on the M-way, 101 db
80 mph cruise 104 db
ACT Cherry bomb is going on later this week, be nice to see the cruise numbers drop a few db .... time will tell
Having accepted that my car is probably too loud for the majority of the population, I have decided to get my car some silencing

Currently it has an ACT Supersports (straight-through), with ACT decat Y, no precats.
Just been playing with a sound meter to get some sound level measurements before the new exhaust goes on ......
With the meter 0.5m at 45 deg from the tailpipe ....
On idle 105 db
at 3000 rpm, 114 db
at 4000 rpm, 119 db
Not that I would want to, but pretty sure there's no track in the UK that would have me

To get some readings from inside the car I wedged the sound meter between the headrest and seat then took some measurments on the road, the meter is roughly "ear level".
Roof panel off, targa up, average readings
At idle, 90 db
30 mph in 5th, 95 db
under acceleration in 3rd up to approx 5000 rpm, peaked at 108 db
70 mph cruise on the M-way, 101 db
80 mph cruise 104 db
ACT Cherry bomb is going on later this week, be nice to see the cruise numbers drop a few db .... time will tell
ChilliWhizz said:
Interesting 
FWIW, I have no precats, Clive F decat Y, box put back to 'standard' (it was sleeved), and it measures a tad over 104db at 4500 rpm (static)
That's interesting too.
FWIW, I have no precats, Clive F decat Y, box put back to 'standard' (it was sleeved), and it measures a tad over 104db at 4500 rpm (static)

I'm expecting something between the two.
A drop of even 5db in the cruise will be a "win", any more will be a bonus
Not really expecting to lose much at the higher rev range.
Mine is pretty well identical to his Chilliness, both in spec and noise readings. The loudest the mainstream tracks allow is 105dB static.
For the quieter tracks, or the evening sessions, which are generally 3-4 dB quieter, I bolt on a pair of additional silencers like these.
They knock about 6 dB off and soften the sound a little.
For the quieter tracks, or the evening sessions, which are generally 3-4 dB quieter, I bolt on a pair of additional silencers like these.
They knock about 6 dB off and soften the sound a little.
Not bothered about track noise. Trackdays are not my thing.
I would like to drop the noise level inside the car though, as each year we do a 2-3k mile trip in Europe and it gets too much for my wife.
Additionally, I understand it's now quite unpleasant to follow the car for any distance (when travelling with friends etc) as it's so loud.
I would like to drop the noise level inside the car though, as each year we do a 2-3k mile trip in Europe and it gets too much for my wife.
Additionally, I understand it's now quite unpleasant to follow the car for any distance (when travelling with friends etc) as it's so loud.
sgrimshaw said:
Do you have a link please.
I bought mine S/H but Daz bought his new.I know TVRMonster did them, you can see them on here.
http://www.pistonheads.com/gassing/topic.asp?h=6&a...
Contact Andy Race, Guillotine on PH.
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