Exhaust legal requirements?

[dog296]

Hey all.

Need a new exhaust for my Polo, and in true fashion, I want to make my own.

Now, itd be a cat back system, to which I'll enlarge to 1.3/4" to optimise proformance.
This is all on a Mk2F 1.0 bread van by the way.

My idea was, use a inline silencer where the original was, something like a cherrybomb, the run the pipe to a Y piece so it can split it, and run the pipes out the back at either side.

So all in all, can I run an exhaust with just a cat, and centre silencer.
I don't think it'll be too loud, as it's only on a 1.0 and I plan to use silencer.

Can any clarify if this is legal, and MOT passable, I understand there's noise limits, but I'm not doing it to be loud, just a nice suttle sound.

[rossrox]

don't really know the answer to your question but I know cherry bombs are very loud! I would look for another make if I were you.

[dog296]

I might use a standard silencer, from another car with the right size pipes, the cherry bomb was just an example.

[squonk]

Have a look at www.motuk.co.uk/manual/contents.htm Sections 7.1 & 7.3

Physically, providing the exhaust is fitted securely and the cat is still present you should be Ok. Other than that the vehicle only has to pass the emissions test, which it should without any problems.

[dog296]

Well this the outcome I want to get.

[stealthstylz]

Where are you going to run the exhaust on the o/s the fuel pump and spare wheel well are in the way.

[dog296]

Ah balls yeh, forgot about the blooming fuel pump!
Ah well, maybe I can still make like a DTM style, still interesting to see that I can get rid of the backbox....

[craig1010cc]

There is no noise test as part of the MOT (at the mo), but if it is too loud then you will get a tug at some point (although unless its VOSA that pull you over, plod wont have any way of measuring the noise with them). There is no requirements as to how many silencers a car needs (ford Kas just have a cat and a backbox). My 1st mini we chopped the back box off and just replaced it with a straight bit of pipe. Was loud mind )the inlaws used to be able to hear me leaving through the village and beyond )

[Hillmanjames]

I've allways had noisy exhausts

First one i made was for my old 1.7 hillman hunter which was just 2" tubing with a single cherry bomb, similar to yours. It was loud! But passed my MOT fine.

Generally, the longer the silencer is, the quiter it will be. You can get ashley ones, that are basicly the same as a cherry bomb, but longer so quieter. Eg:
www.burtonpower.com/parts-by-category/exhausts-safety-equipment/exhaust-parts-universal/jetex-2-silencer-round-80mm-x-410mm-long-jetu405120.html

Had a 1.4 6n polo aswell. That was the fist car i had that the exhaust was mentioned on the MOT certificate, but i knew the tester and he just put " exhaust excessively loud"

Here was my exhaust from the hillman:


James.

[sparkyt]

My old nova 1.4 ran 2in pipe front to back no box no bomb no cat ...it was fine when at idle ..Passed every mot for 4 years ..

[jnoiles]

I have a new style Fiat 500 and its got a cat back stainless steel system with only a tiny back box and no centre box at all. It's passed MOT fine. The inspector actually commented that it was nice to see a clean stainless one instead of grotty Fiat steel ones you get after they've been on the road for 5 minutes.

[fred]

Wouldn't worry about noise, I had a 85 range rover v8 with straight thru pipes, sounded like a Lancaster bomber taking off, passed the MOT mind, just had to depress the clutch when plod was passing lol

[g40jon]

a few years ago i ran my polo gt with just a mid box and no rear silencer. I did keep the cat, which does reduce noise levels a bit. It wasn't as loud as you might expect when idling, but open up the throttle a bit and it was far from quiet. I ran the car like it for 9 months, never got pulled, passed the mot like it. went pretty well too, which suprised me as there must have been little or no back pressure

[dog296]

So it seems I can do the exhaust I want, I'll fit a centre silencer in but not fit a backbox to start with.
I'm only going 1.3/4" so not quite as loud as a 2".

I'll keep a backbox here just incase.

[jjbjoinery]

took my exhaust straight up the side of my windscreen with a rear silencer off a 1.6 polo at the side of the screen on my lada niva, only requirement i had was to put a heat shield round it, was noisy as hell mind but i loved it, looked mint billowing clouds of black smog out when flooring it

[mikeymk]

I considered something similar - Having two cherrybombs, one each side out back. But then i figured they will be louder than one, due to lower pressure in each one.

Plus fitting a silencer on the off side, it'll need to be a very slim/small one because there's less room, spare wheel well and damper mount will be intrusive.

The rest the same - taking the pipe around the back of the spare wheel well is gonna be tight because it'll need to hang under the axle, there's no room between the axle and spare wheel well.

So another thing to consider is putting a rear box in the usual place with one exit there, then a pipe from a second exit straight off behind the rear panel over to the other side through there.
This means having whatever tailpipe you want each side of the car, but one proper silencer box.

I still run one box, one side, one exit. It'll have to do until funds allow, but i like the fairly quiet exhaust because it allows me to hear the bike carbs in all their glory.