Simon
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| posted on 26/11/04 at 10:42 PM |
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Exhaust silencing
Chaps,
I already have two cans (V8 / 5" outer/2"inner) and am thinking that to aid silencing and backpresssure of having a removeable
1.5" perforated tube/wadding down each of the front halves of sidepipes (which are two inch o/d).
According to my calcs (guesswork mostly!) the SD1 had a two inch exhaust system (ignoring the front 1/2) which gives you a 3.142 sq in. If I use
1.5", that gives me a combined area of 3.5 sq in, so should still be better flowing.
What do you think!
Cheers
ATB
Simon
[Edited on 26/11/04 by Simon]
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907
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| posted on 28/11/04 at 07:23 AM |
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Hi Simon,
Firstly, I do not profess to be an expert on such matters, so feel free to disreguard this as compleat tosh.
IMHO I think you would increase back pressure and to a limited degree, decrease sound.
However, before the can is not the best place to do it.
It would be my advice to change the can outlet. i.e. make up a tube of perf with the i/d of a "washer" welded on the end. The o/d of this
"washer" would be 2" to match the outlet pipe or elbow.
Hacksaw though pipe or elbow close to the end of the can and insert perf tube & tack can, washer & elbow to form a single butt weld. Try
before you fully weld.
Many bike cans silence & restrict in this way. My own Yamaha has a 60mm inlet and a 40mm outlet to the can.
Good luck which ever way you go.
Paul G
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Simon
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| posted on 28/11/04 at 11:55 AM |
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Paul,
Thanks for reply - was wondering if I was going to get any!
The problem I have is that the exhausts are now fully welded/painted and I really don't want to go cutting it up again.
I haven't actually tested the fully wadded and welded exhaust yet (waiting till I've painted bodywork, then ex can go back on for the last
(?) time).
For the sake of £25 (a metre of perf tube and wadding) I may make a "pre" silencer. What I may do is stick a washer an inch or so from the
back end of the new bit so sound waves are bounced back up the "pre" silencer.
Hope this makes some kind of sense.
Have you found out how accurate your sound meter is? Think I may invest in one
ATB
Simon
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907
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| posted on 28/11/04 at 12:19 PM |
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Sounds like you'v got it covered Simon.
I'd test run first though. It might be OK.
Meter was spot on. (see latest post)
Paul G
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