no back box?

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ste00
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Post Wed Nov 02, 2005 1:56 am

a mate has offered to make me up a strait through pipe from my cat to the rear of the car and i am wondering if it will pass a mot like this?

it will be standered 320i thickness pipe just no back box at all, i know their are noise regs for a mot but i cant rember them and surly all the chavs out their with 4" exits on 1.1 saxos make more noise than my bm does atm with no back box...
MONSPORT42
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Post Wed Nov 02, 2005 8:33 am

Exhaust technology is all about gas volume and back pressure. You'd need to have bigger pipes and you'd lose torque for most of the rev range - might see a slight increase at the very top end. You would almost certainly fail an MoT. You would really need to look into this and look at what you wanted to achieve and why.
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Andy_magic
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Post Wed Nov 02, 2005 11:20 am

A decent stainless system with both boxes present will make your car sound as good as it gets.
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ste00
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Post Wed Nov 02, 2005 11:38 am

cant afford a decent system atm thats why my mate offering to make up a strait through seemed ideal but if its a mot fail theirs no point...
jonbuoy
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Post Wed Nov 02, 2005 11:42 am

Legally for the MOT the car has to have at least 1 silencer other wise it's a nick. As long as you have got the middle box on it will pass an MOT, the bloke might turn to you and say, "I don't like the sound of that", but tough shit!!
My car went through an MOT with a full stainless on with just a rear box on at first and it was fucking loud, but it passed, well over a 100dbs! :o

The 1.1 Saxo with big exhausts won't be louder than your 320i as there is'nt hardly any grunt like the 6 pot as appossed to the 4 pot in the saxo. Expect it to be a bit deaferning in the cab 8O
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ste00
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Post Wed Nov 02, 2005 12:03 pm

i've had it running recently with no back box (old one was beyond repair... undid the exaust hanger and it just dropped off leaving the pipe behind lol) so i know what it sounds like and i like it (neigborghs dont tho lol)

all it will have is the downpipe, cat (i assume its a cat, has 2 pipes going in and 1 coming out) then strait through to the back of the car (new peice only has to come from the axle to the bumper) so will that be ok?