Toprivetguns
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| posted on 30/8/16 at 12:09 PM |
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IVA FAIL
What a great day for a drive !
Unfortunately didn't quite make the required dba allowance.
The tester measured 100dba which is extremely frustrating, I measured 97dba over the weekend from cold. Would this make a difference?
I Still think this level is unfair considering its a bike engine, however rules are rules.
Now moving forward I'm pretty much out of ideas on reducing the noise level. So far decibel killer fitted, acoustafil, original airbox, sound
insulation engine bay, switch air valves blanked.
Does anyone have a super quiet exhaust I can bolt on for the test ?
Thanks.
Only drive as fast as your angel can fly... !
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loggyboy
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| posted on 30/8/16 at 12:22 PM |
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As good as a fail can be.
Noise has gotta be one of the top first time failure points.
What size can do you have?
Mistral Motorsport
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Bluemoon
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| posted on 30/8/16 at 12:30 PM |
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quote:
Originally posted by Toprivetguns
The tester measured 100dba which is extremely frustrating, I measured 97dba over the weekend from cold. Would this make a difference?
Handy that you have the measured fail value and your estimate as you can attempt to calibrate out the differences. I think the limit pass level 95dba,
i.e. you failed by 5dba, so you need to measurement in your set-up would need to be 97-5 = 92 dba when measuring with your set up.
Dan
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Toprivetguns
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| posted on 30/8/16 at 12:31 PM |
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I don't have the exact size, but roughly about 6'' in diameter.
 
IVA
Only drive as fast as your angel can fly... !
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Jenko
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| posted on 30/8/16 at 12:39 PM |
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Bugger!....that's unlucky.
Do think it's the exhaust noise causing most of the problems?.
MY BLOG - http://westfieldv8.blogspot.co.uk/
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loggyboy
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| posted on 30/8/16 at 12:43 PM |
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quote:
Originally posted by Bluemoon
Handy that you have the measured fail value and your estimate as you can attempt to calibrate out the differences. I think the limit pass level 95dba,
i.e. you failed by 5dba, so you need to measurement in your set-up would need to be 97-5 = 92 dba when measuring with your set up.
Dan
I thought it was 99db ?
Mistral Motorsport
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coozer
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| posted on 30/8/16 at 12:57 PM |
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How about putting some reducers at the top of the headers for the test? Seen plenty of bikes with washer like restrictors. ZZR1100 had them in the
inlet.
My 350lc had two in the expansion chamber, 5" diameter with a 1" hole. Cut them out and boy did it make a difference to the noise, and
response...
1972 V8 Jago
1980 Z750
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Toprivetguns
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| posted on 30/8/16 at 03:51 PM |
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quote:
Originally posted by coozer
How about putting some reducers at the top of the headers for the test? Seen plenty of bikes with washer like restrictors. ZZR1100 had them in the
inlet.
My 350lc had two in the expansion chamber, 5" diameter with a 1" hole. Cut them out and boy did it make a difference to the noise, and
response...
Sounds like a good idea - will start measuring and jump on the lathe.
Only drive as fast as your angel can fly... !
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ReMan
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| posted on 30/8/16 at 04:36 PM |
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I've got a standard quiet can that you can borrow
One of these
SUZUKI HAYABUSA GSXR1300 2002 PAIR OF STANDARD EXHAUST END CANS SEE PICTURES
With a 2" slip pipe adapter?
www.plusnine.co.uk
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gremlin1234
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| posted on 30/8/16 at 04:38 PM |
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quote:
I thought it was 99db ?
I thought it was just under 100dB
so I checked and it is 99dB
due to the way its tested, the angle of the pipe outlet can make a difference too.
also if being picky, the noise section only says about exhaust noise, not inlet, but then again this would be difficult to test them independently.
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BenB
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| posted on 30/8/16 at 08:20 PM |
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Unless you've got a calibrated noise meter (£££££) you can really only do relative noise tests with the cheap(ish) meter. So, as said, now you
know how much over you were on the test you can try and reduce your home testing by the same amount.
The test is a bit silly thoug- my exhausts are basically straight through but because they only test from one side and my mine is a v4 with twin
pipes....
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CosKev3
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| posted on 31/8/16 at 10:39 AM |
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I may have imagined it  but didn't someone on here say the tailpipe should be pointing straight out rather than at the floor for lower noise?
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coozer
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| posted on 31/8/16 at 12:47 PM |
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What's the noise like from under the bonnet, ie: induction??
1972 V8 Jago
1980 Z750
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Toprivetguns
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| posted on 31/8/16 at 05:21 PM |
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The induction is not bad at all.
Oddly enough I retested the car from cold and got my original low reading of below 99dba.
Currently making a new centre part for the silencer and reducing the induction flow with restrictors.
Only drive as fast as your angel can fly... !
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gremlin1234
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| posted on 31/8/16 at 05:33 PM |
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quote:
Currently making a new centre part for the silencer and reducing the induction flow with restrictors.
I guess that will then make the
maximum power at a lower rpm, that should make testing easier too. -ie if you can change max power from say 8000rpm to 7200rpm, it would be tested at
5400 instead of 6000
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BenB
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| posted on 31/8/16 at 05:58 PM |
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My rev counter is fully adjustable so I can set it to whatever I want rather than being a multiple of a certain rpm. This was completely unnecessary
due to the twin pipes however it might help someone else. If the tacho is reading 8000 when the engine is only doing 7000 is anyone going to notice?
Yet it would make quite a difference in dB....
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ReMan
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| posted on 31/8/16 at 07:47 PM |
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You got a u2u
I tossed it in the car this am and am travelling from Essex back to Leicester tomorrow late afternoon/eve
www.plusnine.co.uk
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Toprivetguns
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| posted on 1/9/16 at 09:43 AM |
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quote:
Originally posted by ReMan
You got a u2u
I tossed it in the car this am and am travelling from Essex back to Leicester tomorrow late afternoon/eve
Wow, top man! U2U replied.
Only drive as fast as your angel can fly... !
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