Building a Custom Sports Exhaust for Your Mini

Our project car is a standard Mini with a series of tubes perforations and chambers, which reroute the gases around this complex route that reduces the sample's poor silence that can slow down the expelled exhaust gases, meaning the engine doesn't perform efficiently. To fix this issue, we're going to fit a special type of silencer.

We'll be using an absorption silencer like this, which is designed to absorb sound by changing its properties or snow and reducing the sound it's emitting. This allows the gases to pass through straight through but absorbs the sound waves or pressure changes. To achieve this, we have a perforated tube in the center of the silencer that allows the gases to flow freely while also allowing the sound waves or pressure changes to travel through these holes.

The first layer of our absorption silencer is a stainless steel wire wall, which provides heat protection from the exhaust gases. This layer allows the sound waves or pressure changes to travel into the next layer, where we have fiberglass hair that absorbs the sound. The fiberglass hair is where I'm wearing gloves because it's rather itchy. Finally, on the outside, we have a fiberglass matting and a skin that holds all the component parts of our exhaust together.

After completing the silencer, we're now ready to move on to the next part of our project: selecting the right diameter pipe for our Mini. Since our car is forced induction and turbocharged, we need to use a bigger diameter pipe than what would be used for a naturally aspirated car. We'll start by choosing a two-and-a-half inch pipe for the front pipe, which will help to reduce back pressure. For the rear box, we'll bring it down to a 2.25-inch pipe to attenuate the noise slightly.

With our pipes selected and cut to the correct length of 7.5 feet, we can now start installing them on the engine manifold. The first step is to add a little bend to the pipe, which will help shape it to fit snugly and connect properly to the engine manifold. We'll use a seven-degree bend to ensure that the pipe fits securely in place.

Next, we need to install our catalytic converter. This is the original cat off the Mini, which has 600 cells per square inch. However, since our car needs to run legally on the road and meet emissions standards, we've replaced it with a sports cat that has 200 cells per square inch. This allows exhaust gases to flow better while still taking out the pollutants.

To test the effectiveness of our new catalytic converter, we'll add a can of magic smoke to see how much is emitted by the original unit compared to the sports cat. The results show that the sports cat is significantly more efficient at reducing emissions. With the installation of our catalytic converter complete, we're now ready to move on to the final part of our project: installing our new exhaust system.

Our custom sports exhaust system consists of a spoke exhaust system, which is designed to improve performance and sound quality. While building one from scratch like I have may not be necessary for everyone, it's definitely worth considering if you want to take your car's performance to the next level. With our new exhaust system installed, we'll now need to reprogram the engine's ECU to ensure that it can perform at its best with the new system.

The results of our tuning are impressive: a 23% increase in brake horsepower from the original 170 horsepower to an incredible 209 brake horsepower. Our custom sports exhaust system has truly made a difference in the performance and sound quality of our Mini, making it a little beauty that's well worth doing.

"WEBVTTKind: captionsLanguage: ennow it's time for our resident car tuner and all-round engineering supremo Jimmy Deville to get his hands dirty as he shows us how with a bit of specialist help we can make our cars perform better all over the country there are loads of specialist tuners fabricators and workshops who can add a little bit of magic to your car today I'm at demand engineering in Ipswich and their expertise is exhausts these guys are experts at building four-spoke exhaust systems and today they've agreed to help me to try and improve the power and performance of this ten-year-old mini cooper s by adding a brand-new sports exhaust but before we get onto that let's explain exactly what exhaust systems do well firstly they stop unpleasant and smelly exhaust gases from entering the passenger compartment by passing them to the back of the car secondly they reduce noise if our cars weren't fitted with an exhaust system then the noise could be unbearable not only for the driver and the passenger but uh people outside and thirdly they filter out the pollutants created when the engine fires there are three key components to an exhaust system starting with this weird-lookin set of pipes called a manifold which attaches to the engine now the complexity of the manifold depends on how many cylinders the engine has so this would be for a v8 hence there are eight pipes four on one side four on the other now this would be for a v6 hence there are three outlets on this side now when you build an exhaust it's right here you've got to get it right when three pipes become one because if the diameter of this is too small you're going to build up a back pressure because the exhaust gases can't escape easily enough and that make your engine run like a bag of spanners so I'll be looking to fit a nice wide pipe at this point to make sure this problem is avoided next up is the catalytic converter it takes the harmful emissions hydrocarbons carbon monoxide and nitrogen oxide produced by the engine and reduces them substantially the last part of our exhaust is the silencer now this is the science sir from a fairly standard car and within it we have a series of tubes perforations and chambers and it's reroute the gases around this quite complex route that reduces the sample a poor silence that can slow down the expelled exhaust gases meaning the engine doesn't perform efficiently so I'm gonna fit a special type we're gonna be using a silencer like this which is an absorption silencer now this allows the gases to pass through it straight through but it's this material around these perforation that absorb the sound changing is or snow and reducing the sound it's this that our exhaust needs before I get busy making my sports exhaust I want to find out what the baseline brake horsepower is on my Mini with its standard exhaust fitted and for that I'm using a man and it's portable rolling road right so the guys have just done the first test on the rolling road this car still has 170 brake horsepower normally cars lose power over views but amazingly 170 horsepower is what this car started like with but I reckon I can still improve on that something at this into the workshop and get on with the exhaust first up I need to select the right diameter pipe for the mini give me a hand will be the boss man damn come on in Dan all of this different sized tube how do I know which one is right for our mini because we're forced induction so it's turbocharged we're gonna use a bigger diameter pipe than we might use for a nursery aspirated car okay so we're gonna go down here somewhere yep the two-and-a-half inch for the front pipe yep two and a half of the front pipe and then because it's a road car and we're gonna attenuate the noise a little bit for the road we're going to bring it down to two and a quarter for the back box next we need to cut the pipe to the correct length seven 1/2 feet please sir push start button and that is it now I need to put a little bend into it this will help to shape the pipe to ensure it fits snugly and connects the engine manifold properly for now causing any of that nasty back pressure ok this pipe needs the seven degree Bend I need to turn the hydraulics on then I need to close the clamp out of supports and now it's time to do the bend some degree bends the middle job of building this custom sports exhaust is the catalytic converter this is the original cat off the mini and you can see here this cat has 600 cells per square inch that's quite a fine matrix and it's that matrix that stops the particular and the exhaust gases flowing now here we have our sports cat and this now has 200 cells per square inch so that allows exhaust gases to flow better while still taking out the particular this car needs to run legally on the road let's see how that works here I have a can of magicians smoke and if I pump this down the original one not a lot comes out the other end however if I get our sports cat and do the same for four now we have really good exhaust gas flowing this this should give our car the performance it needs the final part of my sporty exhaust puzzle is the silencer time to roll out my hi-tech absorption one this is a science that going together and this is all about absorbing pressure waves or sound and it does that with several different layers the first layer is a perforated tube and it sits in the center of the silencer now this allows the gases to flow freely but also through these perforated holes allows the sound or pressure waves to travel and they travel from that into here now the first layer they go through is stainless steel wire wall and that's really a heat protective layer from that the sound or pressure waves travel into this which is fiberglass hair that's where I'm wearing gloves because it's rather itchy and then after that we have the fiberglass matting and then on the outside it's all held together with this skin with all the component parts of my exhaust ready all I need to do now is start welding everything together that's the exhaust done now it's time to fit it pitching up a spoke exhaust system is worth considering for any performance car although obviously there's no need to build one from scratch like I have my handiwork finished now it's time to test it out on the rolling road adding my new exhaust system means the cars electronic brain that ECU has to be reprogrammed so the engine can perform to its best with the new system it sounds good but let's see what a handy work has done to the power output hahaha okay that is the rolling road finished with the remap and the custom exhaust is finished and this car now has an impressive 209 brake horsepower that's a 23% increase when its original 170 brake horsepower in my eyes that is custom work well worth doing new little beauty younow it's time for our resident car tuner and all-round engineering supremo Jimmy Deville to get his hands dirty as he shows us how with a bit of specialist help we can make our cars perform better all over the country there are loads of specialist tuners fabricators and workshops who can add a little bit of magic to your car today I'm at demand engineering in Ipswich and their expertise is exhausts these guys are experts at building four-spoke exhaust systems and today they've agreed to help me to try and improve the power and performance of this ten-year-old mini cooper s by adding a brand-new sports exhaust but before we get onto that let's explain exactly what exhaust systems do well firstly they stop unpleasant and smelly exhaust gases from entering the passenger compartment by passing them to the back of the car secondly they reduce noise if our cars weren't fitted with an exhaust system then the noise could be unbearable not only for the driver and the passenger but uh people outside and thirdly they filter out the pollutants created when the engine fires there are three key components to an exhaust system starting with this weird-lookin set of pipes called a manifold which attaches to the engine now the complexity of the manifold depends on how many cylinders the engine has so this would be for a v8 hence there are eight pipes four on one side four on the other now this would be for a v6 hence there are three outlets on this side now when you build an exhaust it's right here you've got to get it right when three pipes become one because if the diameter of this is too small you're going to build up a back pressure because the exhaust gases can't escape easily enough and that make your engine run like a bag of spanners so I'll be looking to fit a nice wide pipe at this point to make sure this problem is avoided next up is the catalytic converter it takes the harmful emissions hydrocarbons carbon monoxide and nitrogen oxide produced by the engine and reduces them substantially the last part of our exhaust is the silencer now this is the science sir from a fairly standard car and within it we have a series of tubes perforations and chambers and it's reroute the gases around this quite complex route that reduces the sample a poor silence that can slow down the expelled exhaust gases meaning the engine doesn't perform efficiently so I'm gonna fit a special type we're gonna be using a silencer like this which is an absorption silencer now this allows the gases to pass through it straight through but it's this material around these perforation that absorb the sound changing is or snow and reducing the sound it's this that our exhaust needs before I get busy making my sports exhaust I want to find out what the baseline brake horsepower is on my Mini with its standard exhaust fitted and for that I'm using a man and it's portable rolling road right so the guys have just done the first test on the rolling road this car still has 170 brake horsepower normally cars lose power over views but amazingly 170 horsepower is what this car started like with but I reckon I can still improve on that something at this into the workshop and get on with the exhaust first up I need to select the right diameter pipe for the mini give me a hand will be the boss man damn come on in Dan all of this different sized tube how do I know which one is right for our mini because we're forced induction so it's turbocharged we're gonna use a bigger diameter pipe than we might use for a nursery aspirated car okay so we're gonna go down here somewhere yep the two-and-a-half inch for the front pipe yep two and a half of the front pipe and then because it's a road car and we're gonna attenuate the noise a little bit for the road we're going to bring it down to two and a quarter for the back box next we need to cut the pipe to the correct length seven 1/2 feet please sir push start button and that is it now I need to put a little bend into it this will help to shape the pipe to ensure it fits snugly and connects the engine manifold properly for now causing any of that nasty back pressure ok this pipe needs the seven degree Bend I need to turn the hydraulics on then I need to close the clamp out of supports and now it's time to do the bend some degree bends the middle job of building this custom sports exhaust is the catalytic converter this is the original cat off the mini and you can see here this cat has 600 cells per square inch that's quite a fine matrix and it's that matrix that stops the particular and the exhaust gases flowing now here we have our sports cat and this now has 200 cells per square inch so that allows exhaust gases to flow better while still taking out the particular this car needs to run legally on the road let's see how that works here I have a can of magicians smoke and if I pump this down the original one not a lot comes out the other end however if I get our sports cat and do the same for four now we have really good exhaust gas flowing this this should give our car the performance it needs the final part of my sporty exhaust puzzle is the silencer time to roll out my hi-tech absorption one this is a science that going together and this is all about absorbing pressure waves or sound and it does that with several different layers the first layer is a perforated tube and it sits in the center of the silencer now this allows the gases to flow freely but also through these perforated holes allows the sound or pressure waves to travel and they travel from that into here now the first layer they go through is stainless steel wire wall and that's really a heat protective layer from that the sound or pressure waves travel into this which is fiberglass hair that's where I'm wearing gloves because it's rather itchy and then after that we have the fiberglass matting and then on the outside it's all held together with this skin with all the component parts of my exhaust ready all I need to do now is start welding everything together that's the exhaust done now it's time to fit it pitching up a spoke exhaust system is worth considering for any performance car although obviously there's no need to build one from scratch like I have my handiwork finished now it's time to test it out on the rolling road adding my new exhaust system means the cars electronic brain that ECU has to be reprogrammed so the engine can perform to its best with the new system it sounds good but let's see what a handy work has done to the power output hahaha okay that is the rolling road finished with the remap and the custom exhaust is finished and this car now has an impressive 209 brake horsepower that's a 23% increase when its original 170 brake horsepower in my eyes that is custom work well worth doing new little beauty you\n"