The newest Toyota Engines for the Tundra pickup truck is the 4.6-liter V-8, delivering more horsepower and more torque than the prior 4.7 V-8, and it has a six-speed transmission behind it to help the 2010 Tundra get much better mileage. Performance-wise, it’s clear that the 4.6 V-8 is no 5.7, but nothing is, and it’s certainly a much more advanced engine than the older 4.7 V-8.

How do they do it? The new V-8 is essentially a slightly destroked version of the 4.7 V-8, but with all the tweaks that the optional 5.7L received when it was developed.

Technically speaking, the new engine includes Dual Variable Valve Timing (VVT-i). Dual VVT-i controls valve timing and overlap on both the intake and exhaust valves. The older 4.7 V-8 had an earlier version of Variable Valve Timing (VVT), which allowed for advancing or retarding the timing of the intake valves only. Dual VVT-i allows for controlling both intake and exhaust valves, in effect creating a more elastic variable cam profile. That’s a big deal.

In an ordinary engine, the cam profile–determined by the shape of the cam lobes on the camshaft–works best within a certain rpm range, forcing a choice between low-end torque and high-end power. At high rpm, an engine requires more air, so the longer the intake valves can stay open, the more top end power the engine can make. However, if the cam keeps the valves open longer, as with a racing cam, problems start to occur at low rpm, reducing torque and ability to idle, and creating the tendency for unburned fuel to exit the engine when both intake and exhaust valves are still open. So you end up with lower engine performance and increased emissions.

Dual VVT-I manages both the intake and exhaust valves to make sure the timing is optimized at low rpm (for more torque) and high rpm (for more horsepower). Another benefit is that it allows for faster heating of the catalytic converter, and with less unburned fuel exiting the combustion chamber, there is improvement in emissions and operating efficiency. By the addition of Dual VVT-I, we would expect to see the 4.6 make more power than the 4.7 at higher rpm, and make the same torque with smaller displacement, with less wasted gas. And that’s exactly what it does.

The new standard 4.6L V-8 may be smaller than the 4.7 V-8 it replaces, but it’s more powerful and much more efficient. Engineering transferred from the optional 5.7 i-Force V-8 help make the difference.

Another factor at work is that with better electronic controls on the 4.6, compression can be slightly increased. Just like the 5.7, the new 4.6 runs on a higher compression ratio (10.2:1 instead of 10:1) than the old 4.7. More compression means more power with every stroke.

The new 4.6 V-8 also uses water-cooled exhaust gas recirculation (EGR), which lowers peak temperatures inside the combustion chamber. In the new 4.6, a computer controls the timing and amount of cooling the exhaust gas receives before it is recycled through the combustion chamber, so the combustion process is never over-cooled. Generally speaking, cooled EGR provides an emissions benefit, but it’s also known that the technique improves overall efficiency, which translates into better mileage.

The new engine is available for sale, as is the older engine, 4.7L V-8 at GotEngines.com. You make the choice, used or rebuilt, we provide the education so you can make the right choice. Cap that with a terrific warranty and excellent customer service and you have a recipe for a great customer experience and the best replacement engines on the market. Call us @ 1-888-344-8044 and ask about the special of the day.