Custom exhaust fabrication may be the first modification you want to have to improve your car system performance. The exhaust system can be improved to give your car more power or better breathing ability.
Some vehicles have a ready-made performance enhancement system, but for most new or rare models, a custom system must be fabricated from scratch. However, before you and your mechanic get to work replacing your tubing, there are important factors to consider, and these are discussed below.
1. Exhaust gas temperature
Your exhaust system works around three important principles. First, when gases are compressed, they heat up. Second, when they cool, they contract and occupy less space. The contraction creates a mini-vacuum, which pulls gases from the cylinder into the exhaust. Finally, exhaust gases leave the exhaust valve during the cool down process.
The performance and emissions of the exhaust system depends on its ability to manage these temperature and volumetric changes. Restrictive systems (where the exhaust is too small) will cause gas temperatures to rise and hence hamper gas expulsion and power production. Overly-large systems conversely mean that exhaust gas temperatures won't rise high enough to combust soot within particulate filters and/or raw hydrocarbons produced from the converters.
Your replacement exhaust system should improve on the flow characteristics of the previous system, or else you stand to lose more than just power. Ensure that the fabricated system is bent properly. Using the right material is also very important for this.
2. Material choice
You have to choose whether aluminized steel or stainless steel is the best material for your car. Many systems currently use the latter owing to its ability to prevent oxidation and corrosion especially at high temperatures. Stainless steel is, however, more brittle compared with the former. Stainless steel systems should last as long as your vehicle, but welding is harder, and stainless steel is also more expensive.
Experts recommend using 304-grade seamless stainless steel if you live near the coast (salty air). If not, you may opt for 604-grade stainless steel which is less expensive. If you choose aluminized tubing, watch out for the seams, which is where rotting commonly begins. You can control this by having the seam at a higher point to prevent accumulation of condensation around it, and subsequent rotting.
3. Design considerations
If you're looking for an exhaust system redesign, bear in mind that more than just tubing adjustment will be needed. For gas as well as diesel models, your mechanic will have to modify the fuel trim, a process that may involve injector replacement, ECM remapping and even sensor changes in some circumstances.
If you have a late-model diesel vehicle and are looking to replace the exhaust, your replacement system should have the correct back pressure to enable it to withstand heat from the burning of soot trapped at the filter. For more information, talk to a professional like Genie Performance Exhausts WA.
I've always driven used cars, and when I first started driving, I made some costly decisions and bought a couple of cars that just weren't worth the money I spent on them. I knew I needed to learn how to inspect a car's engine and how to spot warning signs when I was buying a used car, so I started reading everything I could find on the topic, including basic car mechanics and maintenance. I started this blog to share what I've learned over the years, and I hope my tips will prevent other new drivers buying used cars that will drain their wallet and sap the enjoyment out of driving. I hope you find my posts informative and useful.