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Doug Thorley Headers

Doug Thorley Headers Cat-back Exhaust, Axle-back Exhaust, Headers, Mid-Pipes and Exhaust Products

 

For over 60 years, Doug Thorley Headers has been an innovator in the automotive aftermarket. Driven by a passion for performance headers and superior quality exhaust systems, Doug Thorley Headers is committed to developing 100% American-made products that will reliably deliver maximum horsepower and torque. Doug Thorley Headers has been pushing the limits of automotive technology since first inventing the Tri-Y Header in 1958, and they do it all on American soil.

Every vehicle model is unique, and the Doug Thorley R&D team is constantly working to provide a diverse range of products and applications to meet demand. Whether you are hauling an RV, building up a street hot rod, or just looking to get a little more punch out of your Smart Car, Doug Thorley Headers has the best performance headers to maximize horsepower and torque for your application.

Why the Tri-Y? Serious Horsepower, that’s why!  Invented by Doug Thorley Headers, the Tri-Y header is designed to match the synchronization of the engine firing order, thereby maximizing exhaust scavenging. This design creates the optimum torque and greatest horsepower gains in comparison to any other design.

Doug Thorley Headers operates under the principles of meticulous attention to detail and unmatched craftsmanship while their experienced staff continues to lead the way in automotive performance. Accesspeed is proud to offer Doug Thorley Headers products to our customers. With our low price match guarantee, you will always find the best combination of price and selection at Accesspeed.

 

Below are some of the Doug Thorley products offered by Accesspeed:

Short Tube Headers

Mid-Length Headers

Long Tube Headers

Sandrail Headers

50-State Legal Headers

Cat-back Exhaust

Axle-back Exhaust

Mid-Pipes

 

 


Exhaust, Mufflers, Headers and Tips » Mid-Pipes X-H-Y-Pipes & Race Pipes

Mid-Pipe, H-Pipes, X-Pipes, Y-Pipes & Off-Road Race Pipes

 

What is a mid-pipe?

The mid-pipe is the section of your exhaust system that runs between the exhaust manifold or header and your muffler, or between your catalytic converter and your muffler.  Mid-pipes often improve exhaust flow to increase horsepower and fuel economy.

 

What is a crossover pipe exhaust?

Crossover pipes, such as the H-Pipe, X-Pipe and Y-Pipe, help balance the exhaust pulses from either side of the engine on a V-shape block. This results in a smoother exhaust flow, which can improve horsepower and fuel efficiency.

 

How are Y-pipes different than X-pipes and H-pipes?

While the Y-Pipe is similar in design to the X-pipe, the Y-pipe joins exhaust gasses together into one pipe as it flows through to the muffler. Conversely, X-pipes and H-pipes most often flow through a dual exhaust all the way to the muffler.

 

What is an off-road mid-pipe?

While it sounds self-explanatory, an off-road mid-pipe may have different meanings for those of us to like to spend our time in the dirt and mud, far away from concrete and asphalt. Technically and legally, off-road means the mid-pipe is not legal for street use, and will not pass emissions tests in most states.