What You Need to Replace Your Vehicle's Exhaust System

Back in the olden days—before flip phones and America’s Funniest Home Videos—factory exhaust systems barely made it past the vehicle warranty period. Replacing the exhaust system on a three-year old vehicle was all too common, especially in areas that used salt in the winter to clear the roads.

Beginning in the 1990s, OEM vehicle manufacturers started building exhaust systems out of aluminized steel and stainless steel so they would last through ever-longer vehicle warranty periods. Today, most OEM exhaust systems are made from stainless steel.

That doesn’t mean they last forever. If you’re the type that keeps a vehicle for a long time, you’ll eventually have to replace at least part of your exhaust system. But don’t let that scare you—exhaust systems are not hard to install, and Summit Racing carries a big selection of OEM replacement and performance systems for lots of domestic and import vehicles, plus replacement parts like hangers, mufflers, and catalytic converters, and tools to make the job go a little smoother.

When Good Exhaust Systems Go Bad
A good factory stainless steel exhaust system should last at least five years of daily driving, and longer in drier climates. But rust, salt, and road debris are always busy attacking your pipes. That’s why it’s a good idea to crouch down and inspect the system periodically. Here are some things to look for:

• Excessive movement
• Cracked welds at joints
• Cracks in the exhaust manifold(s)
• Pinholes or punctures in tubing or muffler(s)
• Split or open seams, especially on mufflers
• Loose heat shields
• Loose or broken clamps and brackets
• Missing bolts, clamps, or other parts
• Dents or other damage from road debris, hitting a curb, etc.

Other signs of an exhaust system going bad include a loss of power or an illuminated check engine light (signs of a clogged catalytic converter); exhaust odor in the cabin; vibration under acceleration; and of course, rattles.

Rust can attack an exhaust system from within, too. Those water drops you see at the tailpipe? That’s moisture that has condensed in the exhaust system when the vehicle was parked. If you frequently drive short distances, the exhaust system doesn’t get warm enough to burn off that moisture and it will start eating away at your pipes. Take a long drive once in a while to fully heat up the exhaust system and get rid of that moisture.

Exhaust System Materials
Replacement and performance exhaust systems are available in mild steel, aluminized steel, or stainless steel. Here are the pros and cons of each:

Mild steel systems are strong and budget-friendly, but are very susceptible to rust. They are a good choice for a vehicle that you don’t plan on keeping for a long time or won’t see daily use.

Aluminized steel systems are made from mild steel coated with an aluminum-silicone alloy to help resist corrosion. If the coating is scratched or damaged, the metal underneath will rust. Welded joints and seams will also rust since they don’t have the aluminized coating. Aluminized systems are affordable, and can last three to five years of daily driving depending on the climate where the vehicle is driven.

Stainless steel systems are the most expensive, and for good reason. They can handle high exhaust temperatures (common on vehicles with catalytic converters and turbos) and are very corrosion-resistant. Exhaust pipes made from stainless are also thinner than ones made from mild steel, which can save some weight.

Exhaust components are usually made from one of two grades of stainless steel. 409 stainless steel is what the OEMs and most aftermarket exhaust manufacturers use. It is far more corrosion-resistant than steel or aluminized steel, but will develop surface rust over time that won’t affect durability. A 409 stainless steel system has a life expectancy of eight to 10 years of daily driving.

304 stainless steel contains more chromium and nickel than 409 stainless. It won’t develop any surface rust, but will turn golden brown over time unless you polish it. 304 stainless steel also resists higher temperatures than 409 stainless, making it an excellent choice for high performance vehicles, especially ones with turbochargers that generate a lot of exhaust heat. Of course, 304 stainless steel systems are more expensive, but can last 10 years or longer.

You can learn more about exhaust materials at our Help Center at SummitRacing.com.

Catalytic Converters
If we’ve heard it once, we’ve heard it a thousand times: catalytic converters cost you horsepower. That was true of the first converters introduced in the 1970s, which used a pellet-catalyst design that really choked exhaust flow. Today’s converters have a monolithic/honeycomb catalyst design that poses little restriction to exhaust flow, so you can have your horsepower cake and reduce emissions, too.

Since they’re considered part of the vehicle’s emissions system, converters are designed to last a long time; the current U.S. EPA requirement is eight years/80,000 miles. But like any other part, converters can go wrong. The two most common ways are catalyst meltdown and poisoning.

Meltdown occurs when unburned fuel and oxygen enter the converter and combust. If your converter is glowing red from heat, that’s the reason. Left unchecked, the catalyst brick(s) will melt into a solid mass and block exhaust flow. Other than the glow, the main symptom of a melted converter is sluggish performance.

Catalyst poisoning occurs when the converter is exposed to substances that coat the catalyst to the point it cannot properly function. Causes include:

• Excessive carbon buildup in the exhaust
• Internal coolant leaks
• Use of non-converter-safe gasket sealants
• Excessive oil consumption/burning oil
• Improper fuels or additives

Summit Racing carries OEM replacement and universal-fit catalytic converters from Walker, AP Exhaust, and Bosal. The universal-fit converters flow far better than old bead-style converters, making them ideal replacements for older vehicles that came with a converter from the factory.

We also have manifold-style converters from Pacesetter, Dorman, AP Exhaust, and Magnaflow. Common on late-model vehicles, the design combines the exhaust manifold and a converter into one unit. That allows the converter to heat up very quickly so it oxidizes pollutants at startup when the when the air/fuel mixture is richest.

Other Stuff
Here’s a list of other components you should check and repair/replace when you’re installing a new exhaust system:

• Exhaust manifold(s)
• Exhaust manifold and flange gaskets
• Oxygen sensor(s)
• AIR pumps
• Hangers and insulators
• Clamps

Helpful Tools
• An exhaust manifold spreader expands a manifold or header so you can properly align the bolt holes and prevent the bolts or studs from cross-threading when you tighten them
• Exhaust pipe end shapers help reshape bent, crushed, or flared pipes. Insert the point of the shaper cone into the pipe to round it out, or place the big end over the pipe to reshape flares
• Exhaust hanger pliers make short work of separating rubber hangers from their brackets
• A stud remover tool is designed to grab and hold broken exhaust manifold studs for easier removal. It also works on studs in blocks, cylinder heads, and other engine components
• An air-powered cutoff tool like this one from AIRCAT will make short work of removing an old exhaust system, especially ones with welded joints