Understanding B16B Engine Gear Ratios for Optimal High RPM Power

Understanding B16B Gear Ratios

The Honda B16B engine is a popular high performance 1.6L four cylinder engine that has been used in various Honda and Acura vehicles over the years. One of the allures of the B16B is its exceptional rev happy nature and strong high RPM power band. However, optimizing the engine's power delivery relies heavily on having the right gear ratios matched to your vehicle and performance goals.

B16B Engine Specs

First let's review some key specs of the B16B engine:

• Displacement: 1.6L (1595cc)
• Configuration: Inline 4 cylinder
• Bore x Stroke: 81mm x 77.4mm
• Compression Ratio: 10.4:1 to 11.0:1 depending on version
• VTEC Engagement: 5200rpm to 5800rpm depending on version
• Factory Horsepower: Between 160hp to 200hp depending on version
• Peak Factory RPM Range: 8200rpm to 8600rpm depending on version

As you can see from these specs, the B16B really shines in the upper RPM range thanks to its oversquare bore and stroke dimensions along with Honda's signature VTEC technology on the intake side. This is where picking optimal gear ratios has the biggest impact.

How Gear Ratios Affect B16B Performance

The gear ratios of your transmission dictate the engine RPMs for any given vehicle speed. Lower numerical gear ratios result in higher RPMs for the same speed compared to higher numerical gear ratios. This relationship is important to manipulate to keep your B16B's RPMs in the optimal range.

For example, 1st gear is typically the lowest ratio in a transmission. This means that in 1st gear at relatively low vehicle speed, your engine RPMs can already be quite high in the RPM band. However, the goal is to utilize the full RPM potential of the B16B, which means you want to manipulate the 2nd through 5th/6th gear ratios to maximize performance.

Common B16B Gear Ratio Modifications

Some popular gear ratio modifications for optimizing B16B engines include:

• Lower 2nd Gear Ratio – This keeps RPMs higher when upshifting from 1st to 2nd gear.
• Lower 3rd Gear Ratio – Further optimization for keeping RPM power band centered.
• Higher 5th Gear Ratio – For better cruise RPM range when not in VTEC.
• Higher 6th Gear Ratio (6 speed only) – Further enhancement of top end RPM optimization.
• LSD equipped differential – Important for improved traction in higher RPM launches.

Choosing Gear Ratios for Your Build Goals

There are a few core factors that influence choosing custom B16B gear ratios for your build goals:

• Peak Horsepower RPM – If your build generates peak horsepower above 8000rpm, target higher RPM power delivery.
• VTEC Engagement RPM – Stay above this RPM threshold to utilize performance cam profile.
• Torque Curve – Wider flatter torque curves favor lower gear ratios.
• Performance Setting – Track built engines favor aggressive ratios compared to street builds.

It takes detailed planning and gear ratio adjustment to attain a B16B's full potential. Always factor in build specifications and intended driving environment when deciding which gear ratio combinations to run.

Gear Ratio Calculation Methods

Figuring out your optimal gear ratios requires specific calculations based on engine characteristics and transmission details. Two main methods utilized include:

• Gear Ratio Charts – Matching RPM readings across various vehicle speeds for target power band.
• Gear Ratio Formulas – Inputs like tire diameter, transmission type, and axle ratio used to compute ratios.

Compatibility Considerations

B16B gear ratio swaps are very common, however it's critical to maintain compatibility with components like:

• ECU and Engine Management – Tuning adjustments needed to account for power delivery.
• Clutch and Additional Drivetrain Upgrades – Supporting mods to handle tuning changes.
• Chassis and Wheel Fitment – Gear ratio impacts shift points and RPM trajectories.

Carefully researching component synergy will ensure optimal performance from your new B16B gear ratios.

In Conclusion

Getting the most out of a B16B engine relies heavily on optimizing your gear ratios to keep the engine's RPMs in the peak power band. Lower gear ratios in the middle gears along with a higher 6th gear (if equipped) allow you to maximize the benefits of VTEC engagement and the B16's sky-high redline capabilities. Just be sure to make any necessary ancillary upgrades to support the tuneability unlocked by your new gear ratio setup.

FAQs

What is the stock B16B gear ratio?

The stock B16B gear ratios vary slightly depending on the vehicle application. Most fall in the range of 3.23-3.93 for 1st gear, 1.90-2.13 for 2nd gear, 1.36-1.70 for 3rd gear, 1.03-1.14 for 4th gear, 0.79 for 5th gear, and 0.68-0.76 for 6th gear in 6-speed configurations.

What transmission upgrades support a B16B gear ratio swap?

It's recommended to upgrade to a limited slip differential and high performance clutch such as a twin-disc clutch to properly handle the torque output changes from gear ratio modifications. Reinforced axles and driveshafts also help improve durability.

Do aftermarket ECUs provide advantages over stock ECU tuning?

Yes, aftermarket engine management systems like Hondata KPro allow advanced control of fuel delivery, ignition timing maps, VTEC engagement and lift amounts. This optimizes drivability and power output across the RPM range based on the gearing equipped.

Should chassis braces be added with an aggressive track gear ratio setup?

Chassis stiffening braces for critical areas like the engine bay, rear subframe, and strut towers help improve handling performance by reducing flex which is important when running tight gear ratios intended for circuit usage.