mcramsay
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| posted on 23/2/15 at 08:42 PM |
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Exhaust leaks
Bit annoyed tonight, I have been finishing off my exhaust tonight and due to it being diy and all that I had to use a flexible joint in the center of
it to allow for a little movement, one similar to the following ebay item 171124427111 although it is a clamp on item to eliminate any leak paths I
have welded it in. I pressure tested the exhaust the check for any of my welds leaking and thankfully none did, however what did leak was the flexible
joiner that I have now welded in, it has s small leak where the outer braided wire has been swaged onto the weld on fitting. It's not a huge
leak and I can build some pressure up in the exhaust ( it's not like I am blowing everything out the leaksite) but how much of an exhaust leak
will affect emissions at IVA? As changing the flexible now is a major headache!
A few pics... The first is the drivers side of the system, not the best system but it's my first go with a hacksaw a range of bends and my first
real go with a tig welder!
http://i223.photobucket.com/albums/dd138/mcramsay3003/marlin%20exhaust/4F0F6FAA-966C-4B91-9133-CDE1C1934CF7_zpswfhxdzv7.jpg
This shows the leaksite( my finger shows it
http://i223.photobucket.com/albums/dd138/mcramsay3003/marlin%20exhaust/8505AD3C-3BFB-47C5-A3AA-EC405926884A_zpswdfxwcqv.jpg
[Edited on 23/2/15 by mcramsay]
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britishtrident
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| posted on 23/2/15 at 09:33 PM |
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It should be regarded the same as for an MOT where an minor exhaust leak from a joint or pin hole is not regarded as reason for failure.
Often small leaks will fill with carbon anyway once in use.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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mcramsay
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| posted on 23/2/15 at 09:44 PM |
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I was more worried about the air leak causing a high lambda when doing the emissions test at IVA?
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40inches
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| posted on 24/2/15 at 09:36 AM |
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I spent ages trying to get the lambda right, the correct lambda resulted in high emissions, and vice versa
In the end, and because I was taking a reading with the probe up the exhaust, it turned out to be the 2mm drain hole in the bike silencer that was the
cause Blocking that off got the emissions and lambda down to post 2002.
The slightest leak will screw emissions as read from the silencer outlet.
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britishtrident
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| posted on 24/2/15 at 04:38 PM |
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A pre-cat leak is under positive pressure it has to be pretty big to show in the lambda test. Normally because of the restriction of the cat the
pre-cat back pressure is about 0.5 to 1 psi at idle and about 2 to2.5 PSL when revved to 2,500rpm.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 24/2/15 at 04:43 PM |
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quote:
Originally posted by 40inches
I spent ages trying to get the lambda right, the correct lambda resulted in high emissions, and vice versa
In the end, and because I was taking a reading with the probe up the exhaust, it turned out to be the 2mm drain hole in the bike silencer that was the
cause Blocking that off got the emissions and lambda down to post 2002.
The slightest leak will screw emissions as read from the silencer outlet.
That however is after all the restrictions of the cat(s) and exhaust when testing it is really important to get the probe as far up the exhaust as
possible to get a true reading.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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40inches
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| posted on 24/2/15 at 04:54 PM |
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quote:
Originally posted by britishtrident
quote:
Originally posted by 40inches
I spent ages trying to get the lambda right, the correct lambda resulted in high emissions, and vice versa
In the end, and because I was taking a reading with the probe up the exhaust, it turned out to be the 2mm drain hole in the bike silencer that was the
cause Blocking that off got the emissions and lambda down to post 2002.
The slightest leak will screw emissions as read from the silencer outlet.
That however is after all the restrictions of the cat(s) and exhaust when testing it is really important to get the probe as far up the exhaust as
possible to get a true reading.
Very true, the problem on mine was a very sharp outlet bend, with a resonance chamber at the end of the silencer box, only allowing
about 200-300mm of probe. Got there in the end though, and it sailed through IVA with a carbed bike engine.
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