Lightning
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| posted on 17/5/10 at 05:54 PM |
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Reducing exhaust noise
As I posted earlier I .failed the IVA mainly on noise. It was recorded at 101.7. I have borrowed two cans from Strontium dog. Alas they are too long
and I dont want to cut them.
I bought a noise meter from Maplins and whilst I know that it is not entirely accurate I thought it would be of usefull for comparison. As IVA tested
I got readings of 106.
Now I have 103.7 as I have inserted the old glass fibre wadding that came out of the cans when I repacked them. The DB killer that was in for the test
stopped it all blowing out.
I know dB is logrithmic scale and hence theses figures cannot be used as a direct comparison, however it has come down. I was also thinking of fitting
segments as baffles in the perforated tube.
The above shoould hopefully just last sufficient time for the retest.
Can anyone see any potential problems or suggestions for further reductions?????
Steve
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Dangle_kt
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| posted on 17/5/10 at 06:54 PM |
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what engine?
lag the air box with sound deadening accustic matting for under bonnets
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Lightning
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| posted on 17/5/10 at 08:22 PM |
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Already done
Steve
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Strontium Dog
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| posted on 18/5/10 at 04:25 PM |
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Too long, bugger! You did say you weren't sure.
How about a couple of 2stroke style baffles ie 2 tubes with small holes in them along their length to force the gases to go through the exhaust
packing. Or a plate behind the outlet to deflect the noise away from the testers meter (not sure if you'd get away with that though)!
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David Jenkins
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| posted on 18/5/10 at 06:24 PM |
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Here's an old thread that you might like to read...
Old Fred
...I did this to my silencer when I repacked it - I don't have a meter so I couldn't measure it, but it certainly sounded different - less
harsh.
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Strontium Dog
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| posted on 18/5/10 at 06:28 PM |
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quote:
Originally posted by David Jenkins
Here's an old thread that you might like to read...
Old Fred
...I did this to my silencer when I repacked it - I don't have a meter so I couldn't measure it, but it certainly sounded different - less
harsh.
That's pretty much exactly what I had in mind!
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40inches
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| posted on 19/5/10 at 07:44 AM |
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Have you tried a standard airbox? I know you cant fit one under the panels, but it would confirm or eliminate induction noise as the culprit
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