Lightning
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| posted on 12/5/10 at 06:49 PM |
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Failed IVA today
Noise.
and mirrors
Noise 101.7dB pass now 99dB
mirrors need to raise about 1" so can see over rear arches
Thats basically it except I have to get proof of supressed leads,which they are but not marked.
I could have sorted the mirrors and lead issue out at the test station but could not get the noise down anyway. I have repacked the exhaust and fitted
internal bolt in baffles but no joy. I have 2 exhausts each with silencers and Cats. Trying to think of a solution.
Perhaps a transverse box with 2 inlets and 2 outlets. any suggetions welcome
[Edited on 12/5/10 by Lightning]
 
Rescued attachment rear exhausts.jpg
Steve
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55ant
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| posted on 12/5/10 at 06:52 PM |
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unlucky steve, ive been watching your build for a while.
its a very good fail if there is such a thing. maybe just fit the stock airbox for the test? not sure what your space issues are with space
underneath.
ant
away from cars, now cycling and building TT bikes
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jack_t
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| posted on 12/5/10 at 06:57 PM |
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did you do the noise with the rear cowl off?
cos you would have got a hell of a lot of induction noice with that sausage filter if u did
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jossey
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| posted on 12/5/10 at 06:57 PM |
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sorry to hear about your fail. but in the scheme of things its not too bad.
little bit of work on the exhausts
Then move the mirror and your on the road.
Thanks
David Johnson
Building my tiger avon slowly but surely.
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zilspeed
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| posted on 12/5/10 at 06:59 PM |
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That's a great result.
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Lightning
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| posted on 12/5/10 at 07:04 PM |
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Answers to the above.
The air box wont fit
The rear body section was on and I put in sound deadening inside and covered the rear facing vents too.
Any one know of exhaust specialists down this neck of the woods
(Devon). Been to Apex this afternoon in Collumpton but they cant look at it for at least 6 weeks
Steve
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jack_t
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| posted on 12/5/10 at 07:07 PM |
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how did he measure the sound
1 a measure of each pipe
2 a measure in the middle
3 a measure from just one side
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clairetoo
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| posted on 12/5/10 at 07:08 PM |
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quote:
Originally posted by Lightning
I have 2 exhausts each with silencers and Cats. Trying to think of a solution.
[Edited on 12/5/10 by Lightning]
Are they two separate 2 into 1 ? Do you have a `link' pipe ?
Its cuz I is blond , innit
Claire xx
Will weld for food......
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Lightning
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| posted on 12/5/10 at 07:16 PM |
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4 into 1 back to 2 as in a motorcycle.
He measured each pipe to the side. Not in the middle. Both were within about .2dB of each other
Steve
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55ant
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| posted on 12/5/10 at 07:34 PM |
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are they the stock exhaust cans from the bike?
away from cars, now cycling and building TT bikes
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Lightning
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| posted on 12/5/10 at 07:49 PM |
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No Mk cans and recently repacked
Steve
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andrew.carwithen
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| posted on 12/5/10 at 07:51 PM |
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That's a 'good' fail, Steve. Well done.
I have an R1 can which I used for SVA and, considering they are deemed to be a quiet silencer, I only just got under noise limit (from memory, I
think it was measured at 100.5dB) So I can only conclude that my sausage filter contributed significantly to the overall noise level
I'd say you need to look at reducing induction noise rather than the exhaust's.
Can't you manufacture a bespoke airbox to fit under the cowling? (after all, you did for your Avon IIRC)
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whitestu
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| posted on 12/5/10 at 07:53 PM |
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quote:
I have repacked the exhaust and fitted internal bolt in baffles but no joy. I have 2 exhausts each with silencers and Cats. Trying to think of a
solution.
A turbo?
That should quieten it down!
Stu
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Lightning
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| posted on 12/5/10 at 08:06 PM |
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quote:
Can't you manufacture a bespoke airbox to fit under the cowling? (after all, you did for your Avon IIRC)
Andy, I was going to. Iwas going to make a plenum to fit beneath the scoop with a smooth bend to an induction filter in the scoop outlet. I havnt done
to date as the emissions were ok and didnt want to upset anything. It depends whether Byron wants to retest the emissions on the retest. He said that
as long as the cats stay where they are and only the silencers are altered he will not have to retest the emissions. I had to take the carbs off in
the test to slightly richen the mixture as it was. Then the throttle cable stuck....Oh joy
Steve
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MikeRJ
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| posted on 12/5/10 at 08:38 PM |
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I'd fit a couple of s/h bike cans for the test if you can. Something from a basic tourer/commuter type bike e.g.
Suzuki
bandit would be cheap and effective.
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dave r
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| posted on 12/5/10 at 08:44 PM |
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put 90 degree bends on the ends of the exhuast, facing away from each other ?
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eddie99
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| posted on 12/5/10 at 08:51 PM |
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What the others have said... As good fail as you can get. Hope you get the noise sorted quickly and you'll be on the road in no time. Good luck!
http://www.elitemotorsporteng.co.uk/
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andrew.carwithen
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| posted on 12/5/10 at 09:53 PM |
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Steve,
What dia. is the inlet to your silencers?
If 2" you're welcome to borrow my modified R1 can to see if its significantly quieter than your mk ones.
May help you decide if you should shell out on new silencers
(be an excuse to pop up to have a butchers at the car)
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ReMan
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| posted on 12/5/10 at 10:13 PM |
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|Bandit can/s will make it very quiet they are fairly cheap too
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BenB
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| posted on 12/5/10 at 10:33 PM |
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quote:
Originally posted by dave r
put 90 degree bends on the ends of the exhuast, facing away from each other ?
That's what I was thinking because when I passed SVA with the twin pipes they only tested it from one side so it was not suprisingly rather
quite.
90 degree pipe clamped onto the end and it's happy days
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PeteS2k
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| posted on 13/5/10 at 06:26 AM |
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I got my noise down from 105 to 98.6 (pass!) with a bit of DIY.
- suitably sized Jetex dB insert well lagged with wire wool fitted near the tail-pipe.
- DIY baffle, consisting of a large penny/repair washer bolted to a bracket inserted in the middle of the perforated pipe, still leaving about 10mm
round the sides. Thinking was that it blocked the direct gas and noise path, forcing the flow through the wadding.
I'm sure the above would strangle the engine at full chat, but for pottering down to VOSA, and for running on little or no load it's
fine.
Mine's a 2l Honda S2000 engine - noise test at 6000 rpm. 2 1/2 inch system - 6 inch can with an integral cat in the front.
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Strontium Dog
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| posted on 13/5/10 at 07:21 AM |
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Hi, I'm between Tavistock and Plymouth and I have a pair of YZF1000R Thunderace silencers that you are welcome to borrow and try to see if they
are any quieter! I also have welding equipment should some adaptation be required!
I also don't mind looking at re-packing the cans if necessary!
[Edited on 13/5/10 by Strontium Dog]
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40inches
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| posted on 13/5/10 at 08:00 AM |
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2 cats + 2 silencers on 1 bike engine  , I think I would go with the induction noise theory, what I would personally do is buy a £25 noise meter and
take a reading as is (it doesn't have to be accurate,you are only checking the difference) fit a standard airbox and check again, this will tell
you whether the problem is exhaust or induction and could save time and money in the long run 
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Lightning
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| posted on 14/5/10 at 08:31 AM |
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Strontium Dog U2U
Steve
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Lightning
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| posted on 14/5/10 at 08:34 AM |
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40inches
I think thats a most excellent idea. at least then i would have a clue as to whether it was quieter or not and not waste £90 each retest.
Now what meter to buy????
[Edited on 14/5/10 by Lightning]
Steve
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