When designing the exhaust on our 2002 Tundra, Toyota had to consider a lot of factors, such as emissions standards, packaging, and cost. The system was adequate when our truck was brand new, but after 16 years and 170,000 miles it was time for an improvement. Yes, exhaust systems wear out. This is a result of road salt and rust from the outside, noxious gases on the inside, and flexing as the system repeatedly heats and cools. And all that is assuming you don’t smash your exhaust on a rock before it has time to wear out.
Rather than just replace components, we took the opportunity to upgrade with better components from Walker and Dynomax. Walker makes EPA and CARB-legal replacement components, including the stainless steel catalytic converters, resonators, and mufflers. The parts are made from stainless steel with thicker flanges than stock. They bolt right into place and include everything from the hangers to the heat shields. Walker catalytic converters are even covered by a five-year, 50,000-mile structural warranty.
We have a two-post lift, but there’s currently a Bronco with no suspension living on it, so we installed the exhaust on the ground. Tall (12-ton) Harbor Freight Tools jackstands, lack of rust, and components that fit perfectly made for an easy installation.
We backed the Walker components with a Dynomax Cat-Back System with a Super Turbo muffler. DynoMax Super Turbo mufflers use a three-tube design that channels exhaust flow and reduces backpressure. Each muffler uses fiberglass matting technology to absorb unwanted interior resonance while maintaining a mellow exhaust note. The muffler is complemented by 2 1/2-inch, mandrel-bent aluminized tubing with welded hangers and a stainless steel exhaust tip.
Worried that the Super Turbo muffler will be too loud for your daily driver? At the risk of sounding old, we’ll admit that this was also a concern we had. After performing before-and-after sound level comparisons though, we are happy to report that the new exhaust is only negligibly louder until you get above 3,000 rpm. We also performed emissions testing with the factory components and new components, and found that the Walker and Dynomax combination burns cleaner out the tailpipe. This, combined with a modest increase in mileage and power, makes for a win-win combination, all from components that we were able to install on the ground in just a couple of hours.
The factory exhaust on our Tundra wasn’t as bad as some we have seen, but there was still room for improvement. The new exhaust from Walker and Dynomax is lighter and less restrictive and provides more ground clearance as well.
Walker uses thick flanges on all of its exhaust components. These resist warping, even under high heat, and ensure that you don’t have to worry about exhaust leaks. We got new gaskets from Walker for all of the flanges.
Some budget exhaust systems use clamps to position the hangers, but we prefer welded exhaust hangers. They don’t leave any margin for error, but that wasn’t an issue with the Walker or Dynomax products. And you never have to worry about them coming loose or rattling.
A flex pipe on the Walker crossover tube allows the exhaust to flex when engine torque is applied. This eliminates the potential for cracks that a solid mounted exhaust system can sometimes experience.
Walker retains the factory O2 sensors in their original locations, so there are no concerns about throwing codes. We used antiseize on the bolts to ensure that the O2 sensors come out easily if we need to replace them in the future.
The biggest room for improvement on the stock design is where the two banks of the engine come together. The factory Toyota pipe tapers down to half its original size, while the new Walker pipe is constant diameter to eliminate restrictions.
The new Dynomax Super Turbo muffler is smaller, lighter, and freer flowing than the 55-gallon drum that Toyota puts under the truck. The Super Turbo muffler uses fiberglass matting to muffle noise without choking the engine.
Dynomax uses 2 1/2-inch-diameter exhaust tubing that is slightly larger than the factory Toyota exhaust. This provides a decrease in backpressure without being so large that exhaust gas velocity plummets and cannot scavenge the cylinders when the exhaust valve opens.
If you live in a rusty environment we recommend soaking all bolts ahead of time and having a torch handy. The installation on our desert-dwelling truck only took a couple of hours with handtools though, thanks to the excellent fitment of the Walker and Dynomax products.
Dynomax caps its exhaust system with a slash-cut stainless steel tip. It looks clean without being so big or shiny that someone might confuse our Tundra with a tuner car.
We took sound measurements inside the cab of our Tundra using the Smart Sound Meter app from Netigen. Before-and-after tests were performed on the same stretch of road with the cruise control set to 60 mph and the engine at approximately 2,000 rpm to replicate typical cruising conditions with no measurable increase in noise.
We went to Jack’s Auto Repair before and after we installed the new exhaust components to quantify the change on emissions. Mike Eck ran our truck on the shop’s four-gas analyzer and found that while our truck was still within the allowable limits to pass emissions testing prior to the new components, both hydrocarbon and carbon monoxide were significantly reduced with the new Walker catalytic converters.
Jack’s Auto Repair
Dynomax Performance Exhaust