The B20B and B20Z engine designations have become well-known in the automotive world. Both are four-cylinder engines with a displacement of 2.0 liters, but they have several key differences.
So, what are the B20B and B20Z differences, and why do they matter? The main difference between the two is their compression ratio, timing chain, intake manifold, weight, and cost. Other differences include the design and construction and the power output and performance.
This article will discuss the differences between the two engines, reasons why these differences matter, and why one may be better suited for specific applications.
What is a B20B or B20Z Engine?
The B20B and B20Z engines are part of Honda’s B-series engine family and are used in the Honda Civic and Acura Integra. The B20B and B20Z engines are four-cylinder, 16-valve, 2.0-liter engines.
Here is a table showing some of the most common features of both the B20B and B20Z engines.
| Feature | B20B | B20Z |
| Displacement (l) | 2.0 | 2.0 |
| Maximum power | 200hp | 200hp |
| Maximum torque | 145lb-ft | 145lb-ft |
| Fuel delivery | Multi-point EFI | Multi-point EFI |
| Number of cylinders | 4 | 4 |
| Emissions | ULEV-2 | PZEV |
| Valvetrain | DOHC | DOHC |
| Stroke (mm) | 85.1 | 85.1 |
| Bore (mm) | 87.2 | 87.2 |
The B20B and B20Z engines are famous for engine swaps (replacing an engine with one from a different model or manufacturer) in sport-compact cars. This is because they are both extremely reliable and capable of producing more power with the addition of aftermarket performance parts.
They are also relatively inexpensive, making them an excellent choice for budget builds. Overall, the B20B and B20Z engines are reliable, economical, and powerful engines that are an excellent choice for engine swaps in sport-compact cars.
B20B Vs. B20Z: What’s The Difference?
There are several key differences between the B20B and B20Z engines, and they include the following:
Compression Ratio
The compression ratio is one of the significant differences between the B20B and B20Z engines. B20B has a compression ratio of 9.7:1, while B20Z has a compression ratio of 10.2:1.
This higher compression ratio gives the B20Z an edge in terms of power and efficiency. The higher compression ratio also makes the B20Z more suitable for forced induction applications, such as turbocharging and supercharging, as it can better tolerate the increased air pressure.
The higher compression ratio of the B20Z also makes it more sensitive to the quality of fuel used. For optimal performance, it is essential to use high-quality fuel with an octane rating of at least 91.
Lower octane fuels can cause engine knock, leading to engine damage. On the other hand, the B20B can run on lower octane fuel with minimal risk of engine knock or damage.
Design And Construction
The most notable difference is the block design and engine construction between B20B and B20Z. The B20B has a “square” block design, with cylinders arranged in a square formation. And the B20Z has a “V” block design, with the cylinders arranged in a V-formation.
Accordingly, the square block design of the B20B allows for a lower center of gravity, which improves the engine’s stability and handling characteristics. The V-block design of the B20Z allows for higher power output due to its larger cylinder bores and shorter stroke.
Regarding engine construction, the B20B is a SOHC (Single Overhead Camshaft) engine, while the B20Z is a DOHC (Dual Overhead Camshaft) engine. This difference in construction affects the way the engine operates, as well as its performance capabilities.
Besides, the SOHC engine is more straightforward in design and has fewer moving parts. This makes it less expensive to manufacture and more reliable and durable. Furthermore, the SOHC design allows the engine to run more efficiently, resulting in better fuel economy.
On the other hand, the DOHC engine is more complicated and has more moving parts. This makes it more expensive to manufacture, but it also improves performance capabilities.
Power Output And Performance
The B20B is a reliable and efficient engine but has a different performance capability than the B20Z. On the other hand, the SOHC design limits the airflow through the combustion chambers, resulting in lower power output. Thus, the B20B and B20Z engines have different power outputs, such as
- The B20B engine is rated at 150 horsepower and 141 pound-feet of torque
- The B20Z engine is rated at 160 horsepower and 145 pound-feet of torque
- The B20B’s power output is adequate for most applications but is not enough for high-performance applications
- The B20Z, on the other hand, is a high-performance engine. Thus, the DOHC design allows for better airflow through the combustion chambers, resulting in higher power output
- The higher power output of the B20Z engine is also due to its larger cylinder bores and shorter stroke
Weight
The B20B and B20Z engines also have different weights. So the B20B engine weighs 363 pounds, while the B20Z engine weighs 375 pounds. This added weight of the B20Z engine is due to its larger cylinder bores and shorter stroke.
Cost
The B20B engine is typically less expensive than the B20Z engine. This is because the B20B engine does not require as many costly components as the B20Z engine.
Timing Chain
The B20B engine is equipped with a single-row timing chain, while the B20Z engine is fitted with a double-row timing chain. This single-row timing chain on the B20B engine has a shorter lifespan and is more susceptible to stretching and wear than the double-row timing chain found on the B20Z engine.
Accordingly, the double-row timing chain found on the B20Z engine is more durable and reliable than the single-row timing chain on the B20B engine. This is because the double-row timing chain can absorb more shock and vibration, thus reducing the amount of wear and tear on the components.
Additionally, the double-row timing chain has more teeth, which allows for more precise timing control and a smoother running engine.
Intake Manifold
The B20B features an aluminum intake manifold, while the B20Z features a cast-iron intake manifold. This aluminum intake manifold on the B20B is designed to allow for better airflow and improved performance.
In contrast, the cast-iron intake manifold on the B20Z provides better durability and improved torque. The lighter aluminum intake manifold on the B20B also allows for a lower center of gravity, improving the engine’s overall performance.
Similarly, the cast-iron intake manifold on the B20Z engine is designed to provide improved durability and torque. This makes it ideal for applications that require increased torque.
Reasons Why The Difference Between B20B And B20Z Matters
As we’ve seen, several key differences between B20B and B20Z engine blocks can impact a vehicle’s performance and characteristics. Here are a few reasons why these differences may matter to you:
Performance
As mentioned in the previous section, the B20Z engine has a higher power output and redline than the B20B. If you are looking for an engine that delivers more power and performance, the B20Z may be a better choice.
Fuel efficiency
While the B20B and B20Z are both relatively efficient engines, B20B may be more fuel efficient due to its smaller size and lower power output. This could be a factor to consider if you want to save money on fuel costs or reduce your carbon footprint.
Cost and availability
The B20Z engine is generally more expensive and harder to find than the B20B. If cost is a significant concern, the B20B is a more budget-friendly option.
Compatibility
It’s essential to ensure that your engine block is compatible with your vehicle. Depending on the model and year of your Honda, one engine block may be a better fit than the other.
Tuning potential
The B20Z engine has a higher redline and compression ratio, which may make it more suitable for performance tuning than the B20B. However, both engine blocks can be modified and tuned to some degree, and the specific results will depend on the specific modifications and tuning methods used.
Likewise, the choice between B20B and B20Z will depend on your specific needs and goals. Both engine blocks have unique characteristics and performance capabilities. So, it’s essential to carefully consider all factors before making a decision.
Conclusion
Now that you know the B20B and B20Z differences and why they matter, you should find it easier to choose between them. This choice will depend on the application.
For applications that require a higher power output, such as racing or performance applications, the B20Z engine is the better choice. However, for applications that require a lower center of gravity, such as daily driving or towing applications, the B20B engine is the better choice.
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