4 P Tr2.5 camshaft

Description

TR2 vs TR2.5 testing

We conducted comprehensive prototype testing of the new TR2.5 camshafts in collaboration with 4 Piston Cylinder Heads. These evaluations were performed using a standard 9.8:1 compression 4Piston short block paired with an FK8TD-ported cylinder head and a G30-770 turbocharger configured with the Rampage Fab kit. The goal was to validate performance gains, tuning characteristics, and overall drivability under controlled and repeatable conditions.

With 0.5 psi less boost pressure than the baseline, the TR2.5 camshafts demonstrated consistent gains across the entire powerband. Power continued to climb well into the upper RPM range, and the setup showed clear potential to carry strong output to 8,500 rpm. Vehicle behavior during testing—including chassis squat under load—further confirmed the increased airflow and torque advantages provided by the new cam profiles.

All testing was conducted on pump ethanol at an E55 blend sourced locally, with strict control of fuel consistency and engine temperature throughout. No additives or race fuels were used. Ignition timing, AFR targets, and all ancillary calibration parameters were held constant; only cam timing and the camshafts themselves were changed. This allowed for an accurate and isolated assessment of the camshafts’ true contribution to performance.

The TR2.5 camshafts exhibited no loss in spool and delivered measurable increases in turbine drive energy, translating to improved boost availability. While they require an experienced tuner for optimal results, they proved highly tunable using Hondata software. On-road drivability improved as well, with smoother highway behavior, reduced cabin drone, stable fuel economy, and a refined idle quality.

Based on observed airflow and boost response, we anticipate this setup is capable of achieving 725+ whp, with current results limited only by software constraints rather than mechanical potential. These characteristics also position the TR2.5 camshafts as an excellent choice for high back-pressure applications.

We appreciate the support and collaboration from Josh and the entire team at 4 Piston Cylinder Heads, as well as Deadpool_FK8 for providing the test vehicle.