Why you shouldn’t tamper with the car exhaust system

Daniel Kasirye imported a Toyota Altezza in July. Before getting it on the road, he took it for service at a garage in Katwe, a Kampala suburb. At the garage, he asked the mechanic to, among other things, remove the original exhaust system and replace it with a locally fabricated one. He wanted his car to produce a turbo sound.
When he drove the car for three months, he noticed that although it made the sound that he wanted, it was consuming a lot of fuel. The Altezza was also not as fast as he had expected, since Altezza brands are synonymous with speed because of their sporty engine element.
“When I went back to the mechanic to find out why the car was consuming more fuel, the mechanic could not explain why even after inspecting the car. I suspected he had tampered with something on the car,” Kasirye says.
It was days later, after visiting another garage that Kasirye learnt that changing the exhaust system of any car, has an effect on fuel consumption.
Peter Amadi, a mechanic at Dalas Auto Limited in Bunga points out that Kasirye made a mistake when he replaced the original exhaust pipe system. Amadi is quick to advise that one should maintain the original system as fitted in the factory.
“When you tamper with the factory exhaust system because you want to get things such as sound, you will have removed the original sensors from the original system. You render the engine ‘hungry’ every time. Fuel consumption automatically becomes high because there is nothing slowing down the burnt fumes from the engine. The moment the fuel burns, the exhaust system releases whatever is burnt by the engine as quickly as possible,” Amadi explains. The new exhaust pipe system is also sometimes called the through-pipe.
According to Amadi, the only case where your car will not consume a lot of fuel after the exhaust system has been tampered with is when you only change the muffler to whichever size you want.
The muffler is the tail end of the exhaust pipe system from which fumes are ejected. It is the part at the rear end of your car.
The mistake motorists make is to ask their mechanics to change the entire pipe from the muffler to the engine and fabricate pipes and find ways of connecting it to the engine. When you connect the through-pipe that doesn’t come with oxygen sensors and the catalytical invertor, you pollute the environment. The catalytic converter plays a role of reducing air pollution by removing carbon monoxide and other gases that end up in the atmosphere.

Effect of big exhaust pipes
Alvin Nkini, a mechanic at Munyonyo notes that replacing your original exhaust pipes for bigger ones may not directly affect the performance of your car. Your car performance increases but fuel consumption becomes high regardless of whether your car is turbo or non-turbo.
If, for example, the engine size of your car is 2000cc and you change your exhaust system, your fuel consumption will not double but will instead increase by 40 to 50 per cent compared to if you maintained your original exhaust system. This means you will have to refuel more often like Kasirye.

Cars parked for long
If you park your car for long, when you or the caretaker eventually start the engine and it has run for about 30 minutes, Amadi advises that you rev it first before turning off the engine. This helps to push out water from the engine that would otherwise cause rusting of the exhaust pipe. If you don’t, the exhaust will get damaged. Within a month, the exhaust will rust gradually because the water that was inside the system would have caused rusting.
Mixing of exhaust pipes
Another mistake that motorists make is mix up the size of the exhaust pipe from the engine to the tail. You find different pipe sizes welded together at different points to make one system.
“The worst mistake is to start with a small pipe size where the car cannot breath. The car will suffer to excrete the burnt fumes from the engine and the car will not accelerate properly. An exhaust system is not just a pipe, it is a system on the car that must not be tampered with,” Amadi cautions.

Service of the exhaust system
The most important aspect with the exhaust system is to make sure you are using the right fuel. With new modern cars that have catalytical convertors, if it is choked due to use of low octane fuel, the dirt from the fuel accumulates. This means you will have to use a specialised detergent to get rid of the dirt in the catalytic converter.
Exhaust pipes come with covers on top. When it starts to make noise, do not remove it. Drive to the garage and have it welded to make it tighter because the cover protects the exhaust pipe from road surface damage.