Infinity Design Carbon Fiber Intake for 2017-2021 Honda Civic Type R [FK8] Read reviews

The FK8 Honda Civic Type R is one of the fastest front-wheel-drive cars on the market, but like most modern turbocharged cars, the factory intake has its limitations. The standard system uses a restrictive airflow path and incorporates features designed to reduce intake noise, which can limit airflow as power levels increase.

The Infinity Design FK8 intake was developed to address these limitations, with a focus on improving airflow and providing enough capacity for highly tuned cars.

Highlights

• Proven gains: Independently tested by Tegiwa Imports and TPW Engineering — results showed an increase of 18 bhp and 15 lb-ft of torque, along with improved throttle response and a more pronounced intake sound
• Developed with data: Refined using CFD and tested extensively on the dyno. Data logging was also carried out to check that the gains were repeatable and not simply the result of ECU adaptations
• Bigger intake duct: Redesigned intake duct with a larger opening and increased internal volume
• Smooth airflow: Venturi-profiled inlet tube that extends as close to the turbo inlet as possible, creating a smoother, more direct path for the air to travel through
• Largest filter available: Includes the largest air filter available for the FK8 platform, providing the airflow capacity needed for both standard and highly tuned applications

Dyno Results at a Glance

All power figures are reported in brake horsepower (BHP), measured at the flywheel. 99 RON fuel.

Design

Redesigned Intake Duct

The Infinity Design intake features a redesigned intake duct with a larger opening and increased internal volume. The original rubber seal against the bonnet is retained, while the cross sectional area from the front air feed to the air filter has been increased.

A More Direct Air Path

The factory intake forces air through a 90-degree bend before directing it through a 180-degree turn into the panel filter. From there, the air passes through a short velocity stack within a relatively confined, cuboidal section. The Infinity Design intake takes a more direct approach, allowing air to reach the filter with less than a 45-degree change in direction before entering the main intake volume. The available volume has been maximised to provide an adequate air supply as airflow demands increase.

Venturi-Profiled Intake Tube

The intake tube features a gradual transition from the large cross-sectional area of the air filter to the smaller diameter of the MAF sensor. This design helps maintain a smooth airflow path while contributing to improved throttle response and driveability.

Induction Sound

The tube also shapes the induction sound. Rather than producing a sharp, abrupt intake noise, it creates the deeper, more substantial induction note characteristic of Infinity Design intakes. The gradual change in diameter gives the tube a megaphone-like effect, helping shape the sound produced by the intake.

Integrated MAF & Breather Housings

The MAF sensor and breather housings are integrated into the carbon fibre intake tube, creating a more robust design and a cleaner, more cohesive appearance, particularly when paired with the Infinity Design carbon fibre turbo inlet.

Custom EPDM Coupler

A custom EPDM coupler is supplied to connect the intake tube to the factory turbo inlet. Its internal profile provides a smooth transition between the larger diameter of the intake tube and the smaller turbo inlet, eliminating an internal lip that could otherwise disrupt airflow.

Performance Testing

Test Setup

• Standard car: Completely standard, unmodified car, tested on a Maha MSR500 2WD dyno by Tegiwa Imports
• Modified car: Fitted with a sports cat, intercooler and ECU tune, tested on a Dyno Developments 2WD dyno by TPW Engineering

Test Procedure

For both intake configurations, the vehicle was brought up to operating temperature and fully heat-soaked before testing. The dyno cell temperature was maintained at approximately 3°C above ambient, with the same cell temperature conditions replicated for both intakes to ensure a consistent comparison.

Each intake was tested with three consecutive dyno runs, with the same test procedure used throughout. The vehicle remained completely stock apart from the intake system and was operated on 99 RON fuel for all testing.

Performance Gains on a Standard Engine

The dyno graphs show a baseline power figure of 315BHP, which matches the manufacturer's quoted stock output. With the Infinity Design intake fitted, peak power increases to 329BHP at 6,500RPM, representing a gain of 14BHP, alongside an increase of 15ft-lb of torque.

More importantly, the dyno results show improvements in both power and torque across the RPM range, rather than just an increase at peak power. This means the gains are not limited to the top end of the rev range, but are also present in the RPM range most commonly used during everyday driving.

These improvements are a result of the intake's ability to improve airflow to the engine and reduce restrictions compared to the standard intake system, helping the engine breathe more efficiently throughout the rev range.

Performance Gains on a Modified Engine

The vehicle tested is fitted with a PRL intercooler, Milltek sports catalyst downpipe and non-resonated cat-back exhaust, and has been remapped by TPW Engineering.

On this tuned setup, the performance gains from the Infinity Design intake are even more significant. The dyno results follow the same trend as the standard car, showing improvements in both power and torque across the RPM range, rather than being limited to peak output.

The largest increase is 28BHP at 5,400RPM, demonstrating the benefits of improved airflow under higher engine loads. Peak power increases from 335BHP with the standard intake to 356BHP with the Infinity Design intake, a gain of 21BHP, alongside an increase of 30ft-lb of torque.

These results highlight how the standard intake can become a limiting factor as engine performance is increased through tuning. As power output increases, so does the engine's demand for airflow. An intake system that is sufficient for a standard engine can become increasingly restrictive as airflow requirements rise.

The larger gains seen on the tuned car demonstrate the importance of having an intake system capable of supporting increased airflow demands, rather than becoming a restriction to the engine's performance potential.

Data Logging

The vehicle used for data logging was completely stock and ECUTEK was used to data-log the vehicle with both the factory and Infinity Design intakes on the dyno, providing further validation of the performance results. The data logged included wastegate duty cycle, intake air temperatures measured in the inlet manifold, ignition timing, air-fuel ratio and boost pressure.

Key Findings

• Lower wastegate duty: 1-2% lower until 5,000 RPM, then around 4% lower until redline
• Higher boost: Higher boost pressure throughout the run, from the initial build-up through to 6,500 RPM
• Cooler intake air: Approximately 2–4°C reduction in manifold intake air temperature
• Reaches boost target sooner: Hits the ECU's 1.5 bar boost requirement at approximately 5,900 RPM, compared to 6,400 RPM with the factory intake

Wastegate Duty Cycle

The first comparison is the wastegate duty cycle. The data logs show that in general the Infinity Design intake runs 1-2% lower wastegate duty until 5000RPM, after which it can be around 4% lower until redline.

Boost Pressure

Comparing manifold boost pressure shows that the Infinity Design intake achieves higher boost pressure throughout the run, from the initial build-up through to 6,500RPM. This is particularly interesting when considered alongside the lower wastegate duty cycle discussed previously.

The fact that the intake achieves higher boost pressure despite requiring less wastegate duty suggests that the turbocharger is operating more efficiently, with the reduced intake restriction allowing it to generate greater boost with less actuator demand.

Intake Air Temperature

The manifold intake air temperature data also shows a reduction of approximately 2–4°C with the Infinity Design intake fitted. This provides further evidence of improved intake performance, although the lower temperatures and increased boost should be considered as separate measurements rather than assuming one directly causes the other.

Boost Target

Perhaps most notably, the Infinity Design intake reaches the ECU's 1.5 bar boost requirement for the target torque at approximately 5,900RPM, compared to 6,400RPM with the factory intake. This demonstrates that the improved airflow allows the engine to reach its target earlier in the rev range, highlighting the limitations of the factory intake system.

Air-Fuel Ratio

The air-fuel ratio can next be compared between the stock and Infinity Design intakes. Both systems run close to stoichiometric at lower RPM, before 3500 RPM, at which point both mixtures become significantly richer.

Following this, the stock intake runs at approximately 11.5 AFR, while the Infinity Design intake maintains a slightly leaner mixture of around 12 AFR up to 5500 RPM. From 5500 RPM onwards, the Infinity Design intake returns to 11.5 AFR and remains consistent through to redline.

Although the Infinity Design intake runs slightly leaner than the stock system through the mid-range, the AFR remains significantly richer than stoichiometric under load. This shows that the increased airflow from the intake does not result in an excessively lean mixture, while maintaining the richer AFR required under high engine load.