Weighing up the advantages of an aftermarket exhaust can be a tad confusing, in this guide we have laid out everything you have to gain from an aftermarket exhaust in a simple fashion to make that decision super easy for you.
Why do I need an aftermarket exhaust?
When cars are manufactured, they have to meet government guidelines and be standardised in terms of noise, pollution and pitch.
Essentially the government are pro peace instead of play. We can’t blame them entirely, otherwise we would all be driving around fizz pop and banging down the streets (well hopefully more pop than fizz, I don’t think fizzing is a good sign).
The exhaust is also designed for the originality of the car including its power output, weight, and so on.
If you have made any modifications to the car (I am assuming you have or you want to) then the factory exhaust isn’t going to be able to maximise those changes.
Frankly who likes wasting money? If you are trying to maximise power, the exhaust is a big part of that goal.
It would be like buying a new tool box that doesn’t fit all of your tools in, it’s okay and helps a little but doesn’t totally give you the convenience you were after and you have to leave some tools behind.
Well the BHP is the same as the tools, you won’t be able to access them without the help of a more suitable exhaust.
One of the most significant and trade mark effects of an exhaust system is the sound, some manufacturers produce a sound that they use as “their sound” so that their exhausts are distinguishable among those in the know.
Others offer you a range of sounds varying in pitch and volume depending on the pipework, resonators and silencers that they use in the exhaust system.
The noise can range from that belly rumbling feeling like when you would stand next to the speaker in your school disco (except this is a bit cooler) to a finely tuned performance car sound.
The exhaust also increases the performance of the car as we mentioned above, how fast the exhaust fumes leave the engine affects how fast the air can get to the engine which resonate to how much power can be produced.
Smooth, unobstructed, better flowing exhausts improve the power potential of the engine.
Other factors that affect the power is the diameter of the exhaust, and obstruction reduction in the exhaust but getting the right size is essential.
Thats right, size matters...
Going too wide on a non-turbo charged car can cause the fumes to flow slower at lower revs which causes a loss in torque.
On a turbo charged car a bigger exhaust will usually support more power.
If you have no intention of tinkering with the engine then a smaller size will achieve power gains but if you are making big adjustments then a larger exhaust will support more power output.
Replacing any part in the exhaust system for something less obstructive will benefit the power output in some way. If you are keeping costs down, start with the most obstructive parts to see the biggest gain faster.
This tends to be the catalytic converter and the downpipe.
A cat-back upgrade replaces the exhaust system from the catalytic converter to the end of the exhaust (roughly 2/3 of the whole system).
You will get the middle pipework, rear pipework, silencers and tailpipe (depending on the manufacturer).
Each car will vary in the performance increase but as a rough guide you should see an increase of around 10BHP with this upgrade.
This replaces the exhaust system from the turbo to the end of the exhausts (are the names making sense yet) this includes the catalytic converter.
It gets replaced by a performance cat or by a de-cat.
However, if you are replacing the catalytic converter then a remap is often required as the ECU (Engine Control Unit) will be set to the standard exhaust and it could then cause a lag or a broken engine warning light.
It is worth noting that a de-cat is not road legal in the UK, on the track though you will gain a further 2-6BHP (again varies on the car) and more noise.
So, if the car is purely for the track you might consider it but if it will be on the road too, I would stick to the performance cat.
Resonated or not?
A resonator is a type of silencer that is designed to cut out specific frequencies, people in the know will often be able to tell you if there is a resonator just by listening to car (cool right?).
They can be good if you will be using your car on the road as well as track because when the car is in idle or on the motorway it will be quieter. Then, once you put your foot down, you will hear the roar (anyone else excited thinking about it?)
To summarise, investing in an aftermarket exhaust for your car is going to help you enhance performance, giving you and edge over the other drivers.
Any small change you make is going to help you but for the biggest and most significant power increase the turbo-back is going to level up your cars performance.
For more details on exhausts, more specific to your car, head to our YouTube channel where Adam goes into more detail and shows you some of our exhaust systems.