Toyota Tundra Exhaust Modifications

Jason Lancaster | Mar 27, 2007 | Comments 29

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The new Tundra is a hell of a truck — anyone who’s looked at one will tell you that. Toyota has made a truck that can haul, tow, and race with any half-ton on the road. However, Toyota fit this truck with a relatively quiet exhaust system. If you think your 381 hp 5.7L V8 ought to sound as fast as it is, then this article is for you (BTW, some exhaust dimensions are listed at the bottom of this post).

To start with, Toyota took the time to design a quality exhaust system. In other words, if you never modified your Tundra’s exhaust, you wouldn’t be disappointed. Toyota designed the whole system to be efficient, starting most importantly with the exhaust manifold. That’s because, basically, the new Tundra comes with factory headers (most trucks don’t).

The exhaust manifolds on this truck are some of the most sophisticated factory exhaust manifolds you’ll find — they are a 4 into 2 into 1 design, which has been found to be most efficient for moving exhaust gases quickly. The exhaust manifold is also made out of stainless steel, which is lighter than cast iron (the material most manufacturers use) and more resistant to corrosion. The tubes on the exhaust manifold for each cylinder are also of equal length. Often times, factory exhaust manifolds have unequal length tubes, resulting in different back pressures on each cylinder and contributing to lower performance. By making sure that that cylinders all have equal length tubes, the Tundra’s factory exhaust manifolds are as good as most products available after-market.

In short, the exhaust manifolds on your new Tundra shouldn’t require any modification. If you decide to heavily modify the top end of your motor, then you may want to look into a quality after-market header (when they become available), but for 99% of users, the factory setup is excellent.

From the exhaust manifold (one on each side of the block), your exhaust is going to pass thru two (2) catalytic converters. Unless you intend to race this thing off-road, there’s no good reason to remove your catalytic converters. First of all, it’s illegal to do so. Second, it’s bad for the environment. Third, and most significantly, they really don’t result in that much of a hp loss. Once upon a time catalytic converters would restrict your exhaust significantly. Today’s designs (in the Tundra and otherwise) are fairly performance friendly. Don’t get me wrong — you’d get slightly more performance without them, but do the world a favor and leave them on. Stick with a cat-back exhaust modification.

After the catalytic converters, the exhaust gases from each side of the motor cool somewhat and meet-up at the muffler. Again, the factory system is pretty good. We haven’t tested one, but typically we don’t see a significant hp and torque gain by replacing the factory muffler (3-5hp, 5-10ft-lbs at the most). We are very interested in any dyno testing that anyone has done to confirm or disprove this. However, if you supercharge or otherwise heavily modify the engine the factory muffler should be replaced.

If you decide to replace the factory muffler, the biggest benefit will be the new sound that you hear coming from the pipes. The rumble that we all associate with a V8 is intoxicating, and there are about a hundred different mufflers to choose from to help you get the rumble you want. TRD, Borla, Flowmaster, Gibson, Edelbrock, Magnaflow, etc all offer quality products. While brand is important, it’s more important to know what you want and find the right shop. Most exhaust mufflers, regardless of brand, are interchangeable. Whatever brand you choose, it’s important to remember a few things and ask some good questions at your muffler shop.

First, what do you want? Most people want to hear the exhaust rumble at idle and under acceleration, but not really while cruising on the highway. If you get the wrong muffler, you’ll end up hearing an annoying drone at highway speeds. The experts at the local muffler shop can help (read more about picking the right shop below). Second, do you want something that people can slightly hear when you drive by, or do you want something so loud that the neighbors know exactly what time you leave for work every morning? I hope that it’s the former, but if you decide for the latter, look for words like “racing” or “glasspack”.

Also, do you want a single or dual exhaust? In terms of performance, you usually see the best increase by copying the factory system but upgrading the components. On the Tundra, that would be a single exhaust. But since you’re not going to see much of a performance difference either way, dual exhausts do look and sound better, and that would be our preference.

What material is best? We think that’s a decision that should be based on geography. If you live anywhere near the corrosive effects of saltwater, stainless steel is the smart choice. While it’s more expensive up-front, it will last much longer than galvanized or aluminized steel. People living in dry climates really don’t need to purchase stainless steel — if rust attacks their system, it will be years before anything is damaged.

What about exhaust tips? First of all, go stainless. Anything else will be hard to keep polished. We’ve gone cheap on this in the past and regretted it. Ask to see the tips you’re going to buy along with a cheaper set. If they weigh the same, you’re probably looking at something with a coating. If the expensive set is lighter, you’ve got the real deal in your hands. Tip size shouldn’t be too big either. If you get huge, coffee-can-sized exhaust tips, your back pressure will drop a lot. That’s actually a bad thing — a little back pressure is needed to help the engine perform (it was figured into the design). We recommend sticking with something the same size as your stock exhaust or just a little bigger.

Last, when choosing a muffler shop, ask a lot of questions. We’ve installed a few exhausts and had some bad experiences, so these questions are based on you not making some of the same mistakes we’ve made.

Explain your plan to the shop owner, and then ask for their opinion. If they don’t give you a decent response, you’re not dealing with someone who understands what you’re trying to accomplish. Go somewhere else.
Ask for a brand recommendation. The best shops will tell you about their premium muffler (i.e. Gibson, Flowmaster, etc.) but they’ll also mention their shop brand. Ask them which they would choose. If they tell you there is much difference between the shop brand and the premium brand, make sure that’s not because they’re trying to sell you a more expensive option.
Find out what vehicles they specialize in and if they work with any local car clubs or racing associations. If the shop you’ve found works with a local SCCA chapter or off-road club, they’re probably excellent. If they specialize in import compacts, you may want to go somewhere else.
Ask for referrals and recommendations. Reputable shops will be able to list off five or ten local businesses (mod shops, car dealers, etc.) that they work with.
Ask them how they assemble the system, how the tubes will be bent, if they’re going to use the factory hangers, etc. If you don’t like the answers you get, you might want to shop a little more.
Don’t spend more than about $600 for a cat-back system (installed). We like the TRD product, but for $742.50 (a recent quote we got from a local dealer) PARTS ONLY, we think you could have a nice exhaust system and a half a dozen cases of beer.

Last, check out this recent install by blackgts2002 (must be forum member to see profile), a member of TundraSolutions.com since 2005. He had a dual Flowmaster 70 series put on his new 5.7L Toyota Tundra. We especially like it because of the quiet tone at idle and at steady RPM, while still sounding very impressive under acceleration. The duals look great (he’s chosen what appears to be a quality tip), and the cost and quality is exactly what we’d expect from a good shop. We hope you have the same success with your custom exhaust set-up.
Nice!

2007 Toyota Tundra exhaust system dimensions:

These were found on the TundraSolutions forum — make sure you check your own setup before ordering anything.

Exhaust pipe outside diameter measurements:

At rear of catalytic converters: 2 3/8 inch

From post catalytic flange to factory muffler: 2 1/8 inch

Out of muffler to exhaust tip: 2 3/4 inch

Filed Under: Tundra Exhaust

Tags: exhaust systems • performance

Toyota Tundra Exhaust Modifications

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