Benzine
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| posted on 9/7/14 at 12:07 PM |
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MOT silencer regs
After I got my car through the MOT test last year*, with a silencer, I changed turbo a couple of months later. I then remade the exhaust and ran with
no silencer. This was quieter than when I SVA'd the car with a 2.0 pinto with silencer. Although it's quieter, am I still required
to have a silencer? Would make things easier to run without but if I need one then so be it.
*Running a 1900cc turbo diesel engine
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Mr Whippy
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| posted on 9/7/14 at 12:14 PM |
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I'm sure the road regs require at least one silencer and it should be in a condition to be submitted for an MOT even if it isn't due one
and the MOT requires a silencer and the noise to be within an acceptable limit
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coyoteboy
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| posted on 9/7/14 at 12:33 PM |
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Not sure if you REQUIRE a silencer (define that!?) but all the MOT regs say is that it should be as quiet as a similarly sized production car.
That's hard to define also.
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loggyboy
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| posted on 9/7/14 at 12:46 PM |
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Mot does not require a silencer, and as it (assuming it is) a kit car, as the 'designer of it' (assuming you built it) it would be
impoosible for VOSA to prove it needs one so long as emmisions and sound is not above the approval levels for the time it was approved.
Mistral Motorsport
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Mr Whippy
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| posted on 10/7/14 at 12:05 PM |
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loggyboy
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| posted on 10/7/14 at 12:21 PM |
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Is that intended to argue a silencer is required?
To me that the reason for rejection is merly stating a silencer should meet the requirement, not that a silencer is required TO meet the requirement.
Mistral Motorsport
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coyoteboy
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| posted on 10/7/14 at 12:32 PM |
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Indeed I think it's not required, but you would be hard pressed to claim an unsilenced engine was reasonable - even through a tubby and cat my 2
litre tin top is deafening at idle.
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loggyboy
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| posted on 10/7/14 at 12:47 PM |
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The reason for rejection itself is flimsy on a road car, so on a kit car its virtually uninforceable.
[Edited on 10-7-14 by loggyboy]
Mistral Motorsport
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Ugg10
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| posted on 10/7/14 at 02:29 PM |
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There was a guy called Rauri whi had a cossy Fury and he ran that without a silencer and it was quieter than some NA engines with. Not sure if he is
on here but he may have some views.
On a similar topic, all this fuss about F1 engine noise being too quiet, the whole idea of the turbo is to extract energy from the exhaust to convert
into "useful" work (compressing inlet air) therefore the more efficient the turbo the less energy there is to make noise. Th conclusion
being the most efficient/powerful car will be the quietest ! This fact seems to have been missed by the F1 regulators and the commentators alike.
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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whitestu
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| posted on 10/7/14 at 03:06 PM |
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If the turbo makes it quiet then the turbo is the silencer.
After all a silencer is just a metal housing with stuff inside in line with the exhaust, which is exactly what a turbo is.
Stu
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mark chandler
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| posted on 10/7/14 at 05:06 PM |
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quote:
Originally posted by Ugg10
There was a guy called Rauri whi had a cossy Fury and he ran that without a silencer and it was quieter than some NA engines with. Not sure if he is
on here but he may have some views.
On a similar topic, all this fuss about F1 engine noise being too quiet, the whole idea of the turbo is to extract energy from the exhaust to convert
into "useful" work (compressing inlet air) therefore the more efficient the turbo the less energy there is to make noise. Th conclusion
being the most efficient/powerful car will be the quietest ! This fact seems to have been missed by the F1 regulators and the commentators alike.
Not sure how this works, once the exhaust has escaped the engine system, turbo or not it should have no movement or heat for this to be true so you
would not need a silencer then as nothing to capture or silence, just block the end!
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Mr Whippy
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| posted on 10/7/14 at 10:15 PM |
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I think the main point people are missing is its the MOT inspectors decision which counts and not someone else's interpretation of the rules.
It's very hard indeed to make an engine quiet with just a pipe coming from the engine even if some folk think it sounds better and even harder
to persuade a tester that not bothering to fit one deserves a test cert, after all its they who could lose their testing licence. Show me one person
who has ever got an MOT claiming there turbo is an effective silencer...
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whitestu
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| posted on 11/7/14 at 07:08 AM |
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How does it work with bikes? There are plenty of Harley Davidsons that have no obvious silencer.
Stu
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