Jon Ison
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| posted on 13/3/14 at 09:49 PM |
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Mad idea, good idea ?
Been mulling over trackday noise tests.
What if I drilled a hole in exit pipe of the exhaust, welded a nut over the hole, screwed a bolt through it then welded a penny washer to the bolt
inside the pipe, with the use of a lock nut out side the pipe the washer could be turned/locked into position looking a bit like a throttle butterfly?
Left wide open for minimum restriction close for noise test ?
Good idea, bad idea, just thinking out loud ?
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locost 7 k
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| posted on 13/3/14 at 09:55 PM |
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Try eBay, they have these type of things on there
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owelly
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| posted on 13/3/14 at 09:57 PM |
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It does work as that's similar to what I had up my chimneys but it's the drive-by noise tests that will get you in trouble...
http://www.ppcmag.co.uk
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Jon Ison
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| posted on 13/3/14 at 10:00 PM |
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I never have a problem drive by, failed miserably at Oulton on static, ended up with a red bull can rammed in front end of silencer, passed test can
blew out ran all day no problems, don't ask why it not noisy on the move, static tests are a pain, just the way it is.
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Jon Ison
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| posted on 13/3/14 at 10:01 PM |
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quote:
Originally posted by locost 7 k
Try eBay, they have these type of things on there
I've seen db killers but not somthing you can fix and "tune" with a spanner? Do you have a link to somthing ?
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locost 7 k
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| posted on 13/3/14 at 10:16 PM |
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http://pages.ebay.com/link/?nav=item.view&id=330949311515
I had a similar design on my old car, I had a Y piece in the exhaust with a standard silencer and a straight through with exhaust valve on the tip
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locost 7 k
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| posted on 13/3/14 at 10:19 PM |
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http://www.metropower.org.uk/forum/forums/thread-view.asp?tid=72476&start=126
Towards the bottom is my old system, one of the best mods I done
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Jon Ison
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| posted on 13/3/14 at 10:24 PM |
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Thanks, did it reduce noise significantly?
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mark chandler
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| posted on 14/3/14 at 08:50 AM |
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I have the same problem, good idea !
My car is really quiet one the drive by, it's a mixture of induction noise and panels without soundproof that are the isssue. When I had a side
outlet if I stood between the wheels on the exhaust side of the car it dropped the noise reading so have dragged my exhaust out the back now.
It's still at the limit even now, this sounds like a great plan 
[Edited on 14/3/14 by mark chandler]
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steve m
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| posted on 14/3/14 at 08:57 AM |
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Jon,
I like the idea of a turning penny washer as a butterfly, as my 7 is also very loud, so much so, I cannot really use the car for work
as its too noisy for a 0630 startup, now and again is ok, though
so once you have drilled the holes in your exhaust and fitted your new design, post some pics please
Steve
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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trikerneil
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| posted on 14/3/14 at 10:36 AM |
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I fitted this system to a Harley once to get back some of the backpressure lost with running straight through pipes
LINKY
I got enough backpressure to increase the mid-range torque but it made no difference to the noise.
I had to refit baffles for the MOT.
Neil
ACE Cafe - Just say No.
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