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.

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?

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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?

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I don't have the exact size, but roughly about 6'' in diameter.


IVA

Bugger!....that's unlucky.

Do think it's the exhaust noise causing most of the problems?.

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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

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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...

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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...

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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?

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I thought it was 99db ?

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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....

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?

What's the noise like from under the bonnet, ie: induction??

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.

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Currently making a new centre part for the silencer and reducing the induction flow with restrictors.

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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....

You got a u2u
I tossed it in the car this am and am travelling from Essex back to Leicester tomorrow late afternoon/eve

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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

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