Japan, home to the most technologically advanced culture, has several of the world’s largest automakers. High standards of quality control, reliability, affordability, and efficient engineering have led Japanese manufacturers to be a dominant force in the global automotive market. In this article, a comparison will be made between the modern Japanese engine design methodology for using turbocharged engines of lower capacity, high revs and the American tradition of using large capacity, low revving naturally aspirated engines. Japan’s most technologically advanced performance engine, the 2JZ-GTE, will be compared to America’s newest high-performance engine, the LS2. The 2JZ-GTE engine made by Toyota is a 3-liter (2,997cc), double overhead cam, 6-cylinder in-line engine powered by two sequential turbos and is found in the Supra. Manufactured by General Motors, the LS2 is a 6-liter (5967cc), 8-cylinder (V-configuration) pushrod engine found in the Corvette.
When comparing performance motors, the main thing that matters is how much power and torque the motor produces, right? Err … well, yes and no. There are many factors to consider when comparing engines. However, first, let’s do a side-by-side comparison of the power and torque figures for each engine. General Motors’ LS2 produces an impressive 400 horsepower at 6000 rpm and 530 nm of torque at 4400 rpm. Toyota’s 2JZ-GTE generates a modest 320 horsepower at 5600 rpm and 440 Nm of torque at 3600 rpm. From inspection of these figures, it appears that we have a clear winner. The LS2 produces more power and more torque, so why do I think the 2JZ-GTE is a superior performance engine? An important factor depends on the size of the engine, the LS2 is exactly twice the size of the 2JZ-GTE, but the power and torque figures are not even 25% higher. Why the high level of inefficiency?
The problem with the LS2 is that the engine has several fundamental design flaws and is based on outdated technology. The LS2 has a pushrod design, technically speaking this means it is a type of piston engine that places the camshaft under the pistons and uses pushrods to drive lifters or pushers above the cylinder head to power the valves. Pushrod motors are an old technology, largely superseded by cam designs in Europe and Japan.
The pushrod design is fraught with several problems. First of all, pushrod motors have limited rev capacity compared to camshaft designs. This is due to its higher rotational mass, the valve’s susceptibility to “float”, and the pushrods’ tendency to flex or break at high revs. The LS2’s redline is at 6500 rpm, compared to the 2JZ-GTE’s higher 7200 rpm redline. Second, pushrod motors have limited valve flexibility. Most pushrod engines only have two valves per cylinder (like the LS2). Camshaft engines, however, often use three, four, or even five valves per cylinder for greater efficiency and power. The 2JZ-GTE has four valves per cylinder, making a total of 24 valves for the engine. The LS2, with its two valves per cylinder, has a total of 16 valves for the engine.
In the form of twin sequential turbochargers, perhaps the 2JZ-GTE’s biggest innovative feature compared to the LS2 is the use of forced induction. Because the 2JZ-GTE has a low compression ratio, it allows the operation of turbochargers. A turbocharger is a device that compresses the air that flows into the engine. The advantage of compressing air is that it allows the engine to squeeze more air into a cylinder, and more air means more fuel can be added. Therefore, you get more power from each blast in each cylinder. Turbo charging is perhaps the most efficient way to get power from an engine, both small and large.
By using turbochargers in smaller capacity engines, Japan has been able to create extremely light, high-revving engines that are easily modified and have excellent fuel economy. Simple modifications to turbo cars allow for huge performance gains, especially compared to naturally aspirated engines. As an example, the 2JZ-GTE with an aftermarket exhaust, a front-mount intercooler, and a higher boost setting produces significantly more horsepower than the LS2. If you spend more money, the gains can be huge. Drawing power from a naturally aspirated engine is a lot more work. First of all, if you are looking for great power, you really need to open up the engine and do internal modifications for extra power, unlike a turbo engine that can be modified effortlessly, without opening the engine. Power is often drawn from naturally aspirated engines by modifying the camshafts and working on the engine head. These modifications are expensive and significantly alter the “street friendliness” of your car. That is, they produce a rough idle, have a tendency to stall and are low on fuel consumption.
With all the praise I’ve been giving the 2JZ-GTE, it may seem like the LS2 engine is a low-performance engine. This is certainly not the case, you just have to look at the stock horsepower figures to realize that straight from the car dealer this engine is really fast, with neck-breaking torque. Its design may be dated and its fuel efficient, but there is no question about it. If you are looking for the V8 rumble that many Australians long after, you will definitely be happy with the LS2. The LS2 is very “roadworthy” with 90% of its torque available in idle. This equates to towing, effortless overtaking, and a pure adrenaline rush every time you hit the gas. Additionally, the LS2 has some advantages over the more advanced 2JZ-GTE engine. The LS2 is a much less complex engine and as such when something goes wrong it is much easier to identify the cause and solve the problem. Furthermore, because the LS2 is naturally aspirated (unlike the 2JZ-GTE), there is much less stress on the internal engine components and therefore I would expect a longer engine life than the 2JZ-GTE. .
Today, with fuel prices reaching an all-time high, it is important to ensure that your engine has the optimal balance of performance and fuel economy. Once again, the 2JZ-GTE outperforms the LS2. This is due to the capacity of the engine, the Toyota has 3 liters and the GM engine has 6 liters of capacity. With exactly twice the displacement, unsurprisingly, the LS2 consumes more gasoline. However, this in no way means that the 2JZ-GTE has good fuel economy. Unfortunately, energy comes at a cost and both engines discussed are not economical.
The 2JZ-GTE has numerous clever design features, which contribute to its strength and robustness as an engine. Two of its most advanced features are the use of sequential turbochargers and VVT. VVT stands for Variable Valve Timing and is an advanced technology in camshaft engines where a mechanical device is used to switch between a ‘small’ cam for low and medium revs and a ‘large’ cam for high revs. This allows for good low-rev driving and excellent high-power acceleration at high revs. However, the main engineering feat of the 2JZ-GTE is the use of sequential turbos. Having two turbochargers allows a small primary turbo to start up early and provide excellent low-end boost response and then a secondary turbo to be gradually entered further up the rev range for incredible high-end power. By having this setup, it allowed Toyota to create an engine with phenomenal response anywhere in the rev range and also to leave the way open for some serious modification potential.
To conclude, size definitely doesn’t matter when it comes to high-performance car engines. Japanese high-performance engines are using new technologies such as turbocharging and VVT to deliver phenomenal power and torque figures similar to engines that double in size. The 2JZ-GTE from an engineering and technical design perspective is far superior in all respects to the outdated technology featured in the LS2.