Is it legal to drill a cars exausht?? Uk only Thanks?

Question

I would like to modify my Seat Leon 1.4's exausht system, my friends say simply dril it as they have, but i dont know if this is legal Many thanks Uk only

Answer 1

Ok lets deal with this one step at a time.

Drilling your exhaust tip (the bit where it sticks out at the very back of the car), is legal - pointless, but legal.

Drilling ANY other part of your exhaust system, is VERY illegal, and also VERY dangerous.

When your car's engine burns fuel, it creates excess gasses which come out of the exhaust pipe - and essentially this is done by convected pressure pushing the gas out.
By drilling a hole in the "functional" part of the pipe, you allow air in - and just like how air bubbles at the bottom of a bottle of water will rise to the top, the fresh air outside of the car will be sucked back into the exhaust system.
This causes two major problems.

1> Excessive noise - The police WILL pull you if your car sounds like this.
They can test noise emissions, and you stand to get a fine, criminal record, points on your licence and / or your car impounded.

2> Excessive emissions output - This WILL fail the MOT, it WILL f*** up your engine big time, and it WILL make your car sound awful.
Anyone who knows what a tuned car sounds like can tell the difference between a drilled pipe, and a decent exhaust system.

Advice: if you want that "tuned" sound, then there are a few things you need to get done, and this can be done cheaply.
1> New air filter - approx £40 for a high performance panel, and roughly the same if you choose to go for an air induction kit instead.
2> replace your back box on your exhaust system - from new you would be looking at £150 - £200 fitted, but as I have proved in the past with my cars, you can do both of the above tasks on a shoestring budget of £100 if you make regular enquiries at scrap yards, and keep your eye on ebay.

Hope this helps.

Answer 2

Why would you want to drill it ? it will do nothing at all to help with performance better off getting a proper sports air filter and sports back box then you will get a nice induction and exhaust sound & maybe a tiny bit more performance but not so much that you would notice on the road its not that simple & even those couple of tiny mods may up your insurance premium, for very little advantage if it was that easy w.t.c cars would not spend £10000000000,s developing the cars performance if you could just bolt on a few bits to make the car more powerfull and also you can put on the original bits if you decide to sell the motor and sell the performance parts seperatetly

Answer 3

Drilling it will do no good to your performance and may be deemed illegal. Depends what you do. I too used to drill a small hole at the bottom of the back box to allow condensation to drain out and this was fine. Any more than that may upset the MoT tester, as exhaust fumes can leak into the car.

If you must do something with it, get a properly constructed system that won't b ugger up your performance & emissions.

Answer 4

Volkswagen audi group which includes seat spend countless millions of euros on product development to produce a car that meets uk noise and emissions reg's whilst giving the best performance possible. If your mates think they can do a better job with a black and decker then maybe they should apply for a job at VAG.
It is not legal to tamper with a vehicle exhaust system and it will fail it's MOT test if it's exhaust system is not gas tight.
If you are looking for a performance boost then sell the seat and buy a Golf GTI instead. Simple

Answer 5

I assume that when you drill your exhaust you wish to make it sound "mean". With a hole, it will fail the next MOT. It may also fail on noise too.

The engineers at Seat spent months and months running computer simulations and engine tests optimise the performance of that exhaust system to ensure maximum engine power. By drilling a hole, it could reduce the maximum performance of your engine by up to 20%. Your torque vs. speed relationship, will no longer be flat and the driveabilty of your car will reduce.

It may not be illegal but it is stupid.

Answer 6

i run a garage and i think i will ban all boy racers as i get asked stupid stuff like this all the time, a first car bought by daddy and then some muppet mate comes up with an idea that will give his shopping trolley size engine the power of a rally car without having to spend any money. Save your money and get a higher performance car when you can and when the insurance allows.

Answer 7

Drilling is completely legal. Its your car so you can drill to your hearts content. However if you then drive with a drilled exhaust on a public road your car will be a noise polluter and likely to be stopped by the police. You will be prohibited from continuing and forced to be lifted onto a tow-truck. It will definitely be a MOT failure.

Answer 8

I would say do not do it it will add nothing to the performance and may lead to problems with the MoT test. It could also be dangerous if the fumes get sucked back into the car because they are not be exhausted properly.

Answer 9

Since it won't aid the performance in any way you obviously just want to add a bit of 'character' to this rather bland piece of automotive equipment, so why don't you just remove the main system altogether and fit a straight thru pipe like they did in the thirties and be truly anti-bloody-social.

Answer 10

Seat Leon 1.4, is shopping car, leaf poor litel ting alone, get a 2 litre wit a good strate thru exhaust, get Cat replacement pipe and use insted off cat except fore MOT. Turbo exhaust is alway good becos turbo itselves quiet engin so exhaust can be louderer.