While there are a lot of well built and popular exhaust systems, they don’t always meet everyone’s needs or give you the satisfaction of building your own. For many die hard automotive enthusiasts, not much compares to the joy you get when you first fire up your car or truck and get to listen to the sound of your own one of a kind exhaust system that you built yourself. We’re going to cover some of the various types of do-it-yourself exhaust kits available as well as the true build-from-scratch exhaust systems and show you what you need in order to be able to build your own. Headers can be hand built also, and while it’s not as easy, it’s not necessarily as hard as you might think. All it takes is some patience and knowing that it won’t be perfect the first time, but the beauty is that you will be comfortable enough to modify it until it’s just what you’re looking for. So for all motor, turbo, nitrous or supercharged setups, we’ll cover what you should be looking for and how it’s pretty easy to build your own exhaust.
What kind of setup do you have?
Before you begin, you need to decide what you need. Exhausts come in various sizes and setups and the type you need depends on what type of setup you have. For those that have forced induction such as turbo or superchargers, in most cases you will need a larger exhaust than those who are all motor or nitrous. Your local and state laws also dictate what type of exhaust you can have as some don’t allow you to do any modifications to the exhaust at all. Check your laws before you attempt any modifications. If your car is still in the early stages, we generally recommend to get the exhaust you need when your car has the setup you are looking for. Otherwise, in most cases, you will need to get a different exhaust later which adds to cost.
What kind of exhaust do I need for a turbo setup?
A turbocharger is powered by exhaust gasses so generally the more exhaust you can push through your turbine the more efficient your engine will be and the more power you will make. A 3″ exhaust is generally recommended, and most cards and trucks have enough room to fit 3″ piping. If you are running a turbo on a car or truck that will be producing over 600 horsepower, we would recommend a 3.5″ exhaust or more, depending on your needs. Some big diesel trucks have 4″ exhausts due to the amount of exhaust flow required.
I have a supercharger, what exhaust do I need to build?
Generally a supercharger requires about the same exhaust piping as a turbo setup. Many times a supercharger setup doesn’t produce as much boost as a turbocharger, so the exhaust piping might be a bit smaller, but we still wouldn’t recommend it. Go with the bigger exhaust, so as you upgrade your pulley for more boost, or get other modifications, you won’t have a limiter with your exhaust.
Nitrous or all motor setups
A lot of people with all motor setups often complain that a larger exhaust reduces back-pressure and that’s not a good thing. We hear the same thing from customers with nitrous setups, because they drive around all motor, and only have the extra power once they activate and use the nitrous. The fact is, back-pressure is not good for top end power production, so the bigger exhaust the better. Since an all motor setup usually doesn’t flow as much as a forced induction setup, the exhaust generally doesn’t have to be as large, and is dictated by the displacement and horsepower/torque of the engine. With a larger exhaust on an all motor setup, the power band is shifted, so power comes on later, but has higher peak, so it makes more power, but “feels” less powerful down low which leads people to not be happy with a larger exhaust. This is sacrifice some people must have when building a top end setup. Some customers get around this by having a smaller exhaust, but put a cut out right before the catalytic converter so they can open it up when they need it for racing.
So how can I build my own exhaust?
Here is what you would need in order to build your own exhaust:
- Muffler – We recommend a straight through muffler for those who can handle the extra noise. These flow the best. A chambered muffler doesn’t have the same flow characteristics, and has more back-pressure, but isn’t as loud and generally sounds deeper.
- Piping – We strongly recommend stainless steel piping in areas that are prone to rust. Stainless steel won’t rust and is stronger but more expensive than aluminized metal. Aluminized metal is less expensive and ok for those who live in areas where roads do not have salt and is generally a drier area.
- Exhaust clamps – For those of you who are going to build a slip fit exhaust (when one end of the exhaust literally slips into the other end instead of welding), you will need exhaust clamps to seal the exhaust. Make sure the clamps you purchase will fit around your piping.
- Exhaust flanges – If you are going to put flanges on your exhaust, and will not be building a slip fit, then you will need to buy exhaust flanges. We recommend thicker flanges so they do not warp under extreme heat. Keep in mind that you will need two flanges for each connection, one for each side of the pipes you are connecting.
- Exhaust gaskets – You need to get new exhaust gaskets to put between your flanges to keep the exhaust from leaking. We recommend steel rimmed gaskets for the best seal.
- Exhaust hangers – You’ll need to get new exhaust hangers to be able to hang your exhaust once complete.
- Exhaust Tips – Depending on your setup and what type of exhaust you are building, sometimes you don’t need tips, but generally you would need to get exhaust tips to finish off your exhaust.
- Welder – You need a good mig or tig welder (tig produces nicer welds but requires more skill).
I’m ready to build my exhaust, how do I do it?
Since every car and truck is different it’s impossible to give perfect directions for each vehicle, so we will be general and assume that if you are attempting to build your own exhaust, you have above average mechanical skill and should be able to figure out most of it on your own. How we start is by trying to copy the general design of the stock exhaust system.
- How much piping do I need? – Measure your stock exhaust to find about how much straight piping you need. Add a foot or two for good measure. Determine how many bends you need, and what degree they are. Keep in mind that your new piping will be bigger, so make sure you take into account clearance issues with a bigger exhaust.
- How many hangers do I need? – You at least need to get the same numbers of hangers as your stock exhaust. Depending on the weight of the new system, you might need to add in an extra hanger for support.
Once you have the basic piping together, use a transmission jack or an exhaust jack to try and plan out how the exhaust is going to sit. Add a few small yet supportive spot welds so you can make sure everything fits, but still be able to break the welding to make adjustments.
Leave enough room for your muffler. Measure the length of the muffler, and make sure you have enough room to clear your bumper and still have room for an exhaust tip. If your muffler has a built in tip, then make sure the piping keeps your muffler at the right location so the tip doesn’t stick out too far or not go out far enough.
We are going to cover building your own headers in a different write up, but it’s generally more difficult than a standard exhaust system. You would need a header flange, properly bent piping, and an exhaust collector.
This write up covers a catback exhaust (exhaust from the catalytic converter back to the muffler), or an axle back exhaust (an exhaust from around the rear axle/wheels to the muffler) and not a full exhaust. For a full exhaust, you would also need to purchase a new catalytic converter, which most people opt for the high flow catalytic converts to match their new exhaust. We recommend the same size catalytic converter as the rest of your piping. For turbo setups, you would also need a high flow downpipe. The downpipe connects to either the turbo exhaust turbine or to the turbo o2 housing.
Hopefully this guide gives you some insight into how to build your own exhaust system. It’s a pretty basic instruction set, but with so many different exhaust setups and requirements, we figured the write up would have to be.
We’d love to see your setups! Send us some of your custom exhaust builds and we’d love to feature them here. We also welcome all comments and suggestions on what tips would help someone build a home made exhaust.