Infinity Design Honda Civic Type-R FL5 Carbon Intake

Performance Enhancement for the Honda Civic Type-R FL5

The latest Honda Civic Type-R FL5 is a highly potent and entertaining sports car, boasting a formidable 325 hp and 310 lb-ft of torque. However, the factory intake system has a convoluted airflow path and a small opening, which was identified as an area for improvement.

The design team took a radical approach, using a large, expanding tube with an integrated MAF housing that feeds into a completely redesigned airbox. This new airbox has a significantly larger volume and an 80% larger opening. The system uses a signature double-cone air filter with a 175mm opening and is housed within the new air filter housing.

In addition to the intake system, a standalone turbo inlet tube was developed. This component increases volume and has a smoother radius leading into the turbo, which reduces turbulence.

The Development Process

During the development process, multiple prototypes and models were created. The OEM system uses a simple tube with a small cross-sectional area and a standard panel filter. The decision was made to create a new system that followed the same general path but with a significantly enlarged air opening, mating it to a vastly larger-volume airbox.

This new system doubles the cross-sectional area of the front inlet feed, providing more than an adequate increase in available air. After several iterations, this method produced the best airflow under CFD analysis, showing less turbulence than the OEM system and a vastly increased airflow. The results on both the dyno and during road driving were excellent, with a vastly improved throttle response and low-end torque. Under normal but spirited driving, the engine feels even more eager to accelerate at every RPM, whether under partial or full load.

Air Intake Temperatures & Heat Soak

Intake temperatures were tested by placing thermocouples before the air filter on both the OEM and Infinity systems. The OEM system proved to be a benchmark, maintaining ambient temperatures as low as 20 mph and immediately under full load, with ambient temperatures remaining consistent during full-load, high-RPM acceleration. The Infinity Intake was found to match the OEM intake’s temperature efficiency.

Air Filtration

Within the beautifully shaped carbon enclosures sits a bespoke, short-stack, high-surface-area filter. At a huge 170mm (6 3/4″), it is larger than any cone filter design currently on the market and is designed to take full advantage of the intake tubes by altering the direction of airflow toward the outer walls.

By placing the air filters in front of the inlet tube, the design achieves the largest velocity stack ever seen for this application, which also provides superior laminar flow. The decision to use the largest possible air filter was a meticulous one. A larger filter not only allows for more airflow and power but also remains efficient at its primary purpose—filtering harmful elements from the air—for a longer period without clogging.

Dyno Testing

Dyno tests were performed under strict, controlled conditions on an independent Maha MSR500 dynamometer to ensure a true and realistic result. The stock car produced a nearly identical output to the manufacturer’s claim, with 330 BHP and a perfect, natural power curve. After fitting the intake system, a peak of 347 BHP was achieved, a significant and clear gain of 17 BHP.

From 2500 RPM to 7000 RPM, the torque and power consistently increase through the RPM range, with significant gains in both at 5500 RPM. Rundown losses and ambient temperatures remained identical between the two tests, which were conducted with identical starting oil and coolant temperatures.

Specifications

• 1 x Inlet Tube with integrated CNC MAF Boss
• 1 x Large Air Filter Housing / Inlet Duct
• 1 x Bespoke Infinity Design Air Filter
• 1 x black metal clamps
• 1 x EPDM Flexi hoses with clamps
• 1 x Bracket
• 1 x Fitting Kit