[samplatt]

A lot of non-regular-maintenance jobs are easy & quick to do but break the law - for example, deleting the catalytic converter or EGR from the exhaust system will give your engine better performance and economy, but is illegal since it increases emissions.

Lots of places will do it anyway on a cash job if they think they can get away with it, because it's relatively easy money. A shop replaced my failed catalytic converter ($1200+ replacement) with a straight pipe ($20 pipe and $200 of time) many years ago because they (correctly) assessed me to be a broke-ass student who wouldn't tell on them.

[bArray]

> A shop replaced my failed catalytic converter ($1200+

> replacement) with a straight pipe ($20 pipe and $200 of

> time) many years ago because they (correctly) assessed me

> to be a broke-ass student who wouldn't tell on them.

The mechanic may have even made even more money by scrapping your catalytic converter.

In the UK, swapping the exhaust out for a straight pipe is a common (illegal) modification for greater performance and sound. To get the car through the MOT, you either need to find somebody willing to "look the other way" or re-weld the original exhaust in place.

I've seen in many scenarios "boy racers" dipping the clutch and coasting the car by the police. If your car is making a sound resembling a Spitfire you're sure to get pulled over, where they'll use a road side test kit and confiscate your car.

Some other popular cheap modifications include completely removing the air-filter (dangerous), stretching tires to create low-profile wheels (extremely dangerous if they let go [0]), putting the car on a diet (ripping out all interior, seats, etc), running contaminated fuel (either diesel/petrol mixes [1] or running farmer's diesel) - the list goes on.

There are also some processes for purposely causing the car to backfire regularly (especially on a down change, with quite large flames) and getting more "bang" from the fuel. At one point we were also experimenting with the idea of using the starter motor strategically to aid engine acceleration - but nothing ever came of it.

[0] We had a car crash on the motorway into the central barrier, which then caused all of the tires to instantly disintegrate - all at ~90 mph (~145 kph).

[1] We once had a vehicle literally explode when unburned fuel collected in the catalytic converter/exhaust and suddenly decide it wanted to be on fire. This in itself wouldn't have been an issue if a) somebody noticed and b) it didn't then ignite the fuel lines.

[samplatt]

>The mechanic may have even made even more money by scrapping your catalytic converter.

Oh, certainly. Not to mention that removing it would have been a larger & more difficult job, which I'd have to pay for... OR they can get less money but it's (very) easy money.

>completely removing the air-filter (dangerous)

Good god... Who the hell does that? What ricer would willingly risk killing their motor from eating some leaves (or a piece of gravel!) for a minuscule performance increase? The risk:reward scale there is just bananas.

[bArray]

I should probably add, at one time I had a throw-away car, it cost <£100, it's scrap value was £100+ and at the time the MOT and tax was registered to the car itself and it had a few months left of road-legal use.

Before scrapping it I decided to drive it around as a "risk free" car. The exhaust fell off (so not even a straight pipe), the battery was dead (had to push start it everywhere), the clutch was teetering on death, brakes were merely a suggestion to your speed (it had drums), the radiator leaked, the oil was probably as old as the car, tires were barely legal and it had no working headlight bulbs.

We ripped out all of seats, removed the air filter, filled the tank with contaminated petrol (had diesel in it - added a small amount of nitro-car fuel to balance it out) and drove it very hard.

I ended up using it for quick 20 minute journeys (that's about how long it took for all the coolant to leak out). We would leave it unlocked with the keys in the ignition - I think it was more hassle to whoever tried to steal it. The car survived long enough to drive itself onto the back of a flat-bed lorry to be taken to the scrap dealers once the MOT and tax ran out.

This is not uncommon either, many people get "traders plates" just so that they can drive barely legal cars around before getting rid of them.

[bArray]

> Good god... Who the hell does that? What ricer would

> willingly risk killing their motor from eating some leaves

> (or a piece of gravel!) for a minuscule performance

> increase? The risk:reward scale there is just bananas.

A lot of people do it. In the UK you've also got tonnes of rain regularly too, meaning all sorts of crap is sprayed into the engine bay area, both dry and wet.

The performance gain is surprisingly high given how simple the action is, the throttle becomes more responsive and you can audibly hear the engine taking gulps of air. Of course that comes with the associated risk. If you're a student with a £300 car and you want to pretend it's a race car, little tricks like this cost nothing for a little speed boost.

[kylehotchkiss]

The answer is: every old Japanese car with their hood open on a Friday evening at sheetz.

[ta999999171]

This guy knows what he's talking about!

Also, Sheetz is a regional gas station (once) popular with street and track racers. I guess it still is, but their food quality has gone through the floor.

[kylehotchkiss]

It's always been through the floor. If it seemed like it was good before, that's the nostalgia filter kicking in.

Wawa for life.

[dsfyu404ed]

>Good god... Who the hell does that? What ricer would willingly risk killing their motor from eating some leaves (or a piece of gravel!) for a minuscule performance increase? The risk:reward scale there is just bananas.

Statistically nobody but every mechanic remembers the story of "that one idiot".

[adrianN]

> At one point we were also experimenting with the idea of using the starter motor strategically to aid engine acceleration - but nothing ever came of it.

This is how the hybrid car was born.

[bArray]

> This is how the hybrid car was born.

Yes :) We were quite amused to have had the idea a few years before it's popularization!

[everdrive]

Frustratingly, removing your catalytic converter has a very tiny effect on performance, and an enormous effect on emissions. Kids into car culture tend to hold very superstitious ideas about cars and performance. (eg, the manufacturer intentionally hobbled your car with a restrictive cat-back exhaust, and replacing it with something loud and terrible will "unlock" a significant amount of hidden horsepower.)

[tomatotomato37]

The reason for the superstition is that it is true ...in the 70s when the latest in emission technologies was clogging the exhaust with platinum balls. Now-a-days converters are built intelligently & removing it just reduces performance by fucking up the O2 sensor readings unless you also dump a grand on a new ECU

[bArray]

> Now-a-days converters are built intelligently & removing it

> just reduces performance by fucking up the O2 sensor

> readings unless you also dump a grand on a new ECU

You can also get a piggy-back ECU for the purpose of sending false sensor data - it's quite a bit cheaper.

[jacobush]

At first I couldn't see how this could work - I assume there is no yearly government check up on your cars including emissions?

https://www.bilprovningen.se/boka-besiktning.html

[samplatt]

Correct, not in Australia.

[pengaru]

In my experience when doing illegal modifications the transaction is not only in cash but also 100% off the books; there's no need for POS receipt shenanigans.