Toyota Tacoma Headers: Bolstering Power and Sound

The term “header” is used to define an aftermarket replacement for your stock exhaust manifold(s). Stock exhaust manifolds are typically made of heavy cast iron, and are designed by auto manufacturers as a means to an end.

The primary concerns of the manufacturers are simply getting the exhaust from the cylinder head to the exhaust system, reducing sound, and keeping manufacturing costs low. A header, by contrast, is almost always designed with performance and sound in mind. A header is constructed of mandrel bent round tubing that is much thinner than the cast iron of the stock manifold.

As soon as you bolt on a set of headers, you could be losing as much as 50 pounds of unneeded weight! The smooth surface and flowing bends allow for better exhaust flow, increased resonance (better sound), and better heat retention abilities.

Headers also perform a secondary performance function, scavenging. Scavenging is the momentum of the exhaust gases escaping through the header, and creating a vacuum behind that helps to pull the exhaust gases out of the combustion chamber of the engine. The faster the exhaust gases escape, the faster and more fully the combustion chamber can fill with air/fuel mixture. End result: more horsepower!

The only difference between a header for a 4-cylinder application and a V6 application is the quantity. Because the 4-cylinder engine only has one bank of 4 cylinders, it requires only a single header.

The V6 engine has 2 banks of 3 cylinders each, located on either side of the engine block. Therefore, it requires 2 separate headers, one for each bank, or side. With a V6 engine configuration and a single exhaust, you will also need a “y-pipe”.

This is nothing more than a pipe to connect the two header outlets to the single exhaust. There are many applications commercially available, or you can have one made at a local exhaust shop.

Most headers are made of two materials, mild steel or stainless steel. Mild steel is sort of the “entry level” point for headers. Mild steel headers are typically much cheaper to purchase; however, they are far more prone to oxidation and rust. Stainless steel headers will cost a significant amount more at the initial purchase, however, they will typically last much longer. Stainless steel will not rust and is better at retaining heat. This results in lower under-hood temperatures, and cooler air making its way inside the engine.

Once you decide upon the construction material, you also will have to choose an exterior finish for your header(s). There are 3 basic finishes: bare, painted, and ceramic coated.

Bare headers: are exactly what they sound like, no finish on the header. These are typically priced the lowest, but have the shortest length of service. As you can imagine, a piece of steel without any protection, being subjected to water, road salt, and engine compartment temperatures, will eventually corrode.

Painted headers: are basically the “middle of the road.” They are slightly more expensive than bare headers and will last slightly longer. These headers are coated with a high-temperature paint. It provides a basic layer of protection, but as it ages and begins to chip, corrosion will eventually become a problem.

Ceramic coatings: are the “top of the line” in the header game. Ceramic coatings protect the appearance and integrity of the header, as well as keep heat inside the header tubes. This prevents corrosion, and keeps under-hood temperatures lower, allowing a cooler, more dense charge of air to reach your engine. This means more horsepower.

Headers in several different tubing thicknesses. The two most common are 16ga and 14ga. 16ga is typically used in passenger car applications, and is the thinner of the two. 14ga is used for heavy-duty applications, like trucks and towing vehicles.

The thickness of the tubing has an impact on longevity as well, with the thicker material usually lasting longer since it’s less prone to cracking and rust. The thicker tubing is also less susceptible to engine vibrations.

If your Tacoma is rear wheel drive, or lowered, there may be some issues with ground clearance. A full long tube header may be too long, and contact the pavement beneath the truck. For these applications, a “shorty” header may be required. This just means that the primary tubes, and the header overall, are shorter from top to bottom than a full-length header. They are designed for fitting into tight spaces. You will make a little less power at the top end of the RPM curve, but still have plenty of low-end grunt.

While the idea of swapping out an exhaust manifold for a header seems easy enough for a mechanically inclined person, sometimes it can be a downright nightmare. Space is the key issue here.

Anytime space under the hood is at a premium, header installation will become more difficult. If your vehicle is more than a few years old, rust can also become a problem. Removing rusted nuts or bolts can become quite problematic, possibly resulting in removing the fasteners with a torch, drilling out the remainder, and rethreading the part.

With those caveats mentioned, installing a set of headers is something you can do with a friend on a Saturday. The only specialty tool needed is a torque wrench. Be sure to follow the manufacturer’s directions.

The keys here are:

1.  Follow the torque sequence recommended by the manufacturer.
2.  Do not over torque the fasteners!

Over torquing the fasteners can cause the header flange to distort, resulting in a surface that will no longer seal.

To keep your header(s) performing at their best, periodic inspection and maintenance is a must. You should routinely check header sealing surfaces as well as fastener torque. Immediately replace any leaking or damaged gaskets. Header fasteners WILL loosen. Recheck the fastener torque at least monthly.

Also, inspect the flanges for distortion. If you have a leak, take the time and check the flange(s) with a straight edge. If they are no longer straight, they can possibly be machined to the correct tolerances, or header replacement may be necessary.