Unleashing Performance: Harnessing the Power of the Tomioka Racing Manifold for the Porsche

In 2015, EDO Performance conducted testing on a 2008 Porsche 911 (997.1) with the objective was to maximize the performance of the Porsche 911 (997.1) Turbo on a fresh platform. Additionally, we set out to create a Stage 1 Performance Package, integrating various aftermarket enhancements such as the COBB Access Port, Agency Power Titanium Cat-Back Exhaust, Agency Power Boost Recirculation Valves, Tomioka Racing Stainless Steel Exhaust Manifolds, and Torque Solution Semi-Solid Engine Mounts.

Understanding the Modifications

1. Exhaust Manifolds and Cat-Back Exhaust,

An exhaust manifold is designed to reduce back pressure and improve an engine's volumetric efficiency, resulting in increased power output. Aftermarket cat-back exhaust systems, like the Agency Power Titanium Cat-Back used in this project, replace the smaller and heavier stock exhaust components. This particular cat-back reduced weight by 20 pounds from the rear of the vehicle and improved engine responsiveness. Additionally, increasing the diameter of the cat-back exhaust further enhances flow efficiency, leading to additional power gains.

2. Engine Management with COBB Access Port

Engine management is a critical aspect of a vehicle's operation, controlling various engine functions, including fuel injection, ignition timing, boost pressure, startup and idle behavior, safety measures, rev limits, and more. The COBB Access Port allows for tuning and customization of the factory engine control unit (ECU).

3. Agency Power Boost Recirculation Valves

Boost recirculation valves (BRVs) contribute to the longevity of turbochargers. These valves open when sufficient pressure builds up in the intake pipe and vacuum is present in the intake manifold, a condition that occurs when the throttle is opened to create boost pressure and then released, creating a vacuum. When the BRVs open, they release the pressurized air from the intake piping either back to the turbocharger or vent it to the atmosphere. Additionally, BRVs help maintain turbine speed during gear shifts, improving drivability.

4. Engine Mounts

Factory engine mounts are made of solid rubber, designed to absorb engine vibrations and provide a more comfortable cabin experience. Replacing them with semi-solid polyurethane engine mounts, like the Torque Solution Semi-Solid Engine Mounts used in this project, transmits more vibration from the engine but allows the engine to sit more securely in the engine bay, reducing fore-and-aft motion and improving power transfer through the drivetrain.

Testing Methodology and Parameters

All experiments were conducted at sea level altitude, with an average humidity of 30% and an average outside temperature of 86°F (30°C).

A Dynapack 5000 Dynamometer was used to measure wheel horsepower (WHP). Before each configuration, the vehicle's ECU was reset to eliminate potential skews in the dynamometer readings. The reported horsepower values were calculated by averaging three dynamometer pulls for each configuration. ECU tuning was performed to measure power output across all configurations.

Configurations Tested

1. Configuration 1 (Baseline): Original 2008 Porsche 911 Turbo (997.1)

The car was purchased in 2014 with its original factory settings (ECU calibration) and hardware intact.

2. Configuration 2 (Stage 1): Installation of COBB Access Port, Agency Power Titanium Cat-Back Exhaust,, Agency Power Boost Recirculation Valves, Tomioka Racing Stainless Steel Exhaust Manifolds, and Torque Solution Semi-Solid Engine Mounts. 

Starting from Configuration 1, the original cat-back exhaust, exhaust manifolds, boost recirculation valves, and engine mounts were replaced with the aforementioned aftermarket components. The COBB Access Port was also installed to manage the OEM ECU.

Results:

The stock configuration delivered torque at lower RPMs, but after installing aftermarket performance parts, the car's power output skyrocketed from 418.2 whp to 569.1 whp—a staggering 36% increase. The addition of an Agency Power Titanium Cat-Back Exhaust, boost recirculation valves, Tomioka Racing Stainless Steel Exhaust Manifolds, and COBB Access Port significantly improved the car's responsiveness. These modifications resulted in a much smoother power delivery across the entire rev range, right up to the redline. Moreover, the Agency Power BRVs enabled the car to maintain higher boost pressures, thereby increasing power and keeping the turbines spooled during gear shifts.