Greddy RX35 Intake Manifold/ Billet Throttle Bodies - Import Tuner Magazine

How do you take something that’s already good and make it even better? Just ask aftermarket tuning manufacturer Greddy and their newest intake manifold designed for the Nissan R35 GT-R. The R35 RX surge tank, otherwise known as an intake manifold, started off as a conceptual idea that eventually blossomed into a budding reality over a time span of a few years by Greddy engineers. The manifold design is unlike anything Nissan enthusiasts have witnessed for the R35. The cast-aluminum intake manifold was developed and manufactured in Japan using valuable data and track analysis with proven results upon extensive testing using the 200-plus-mph Greddy 35RX GT-R, as well as in the United States with the 8.79-second quarter-mile SP Engineering/HDM GT-R.

The RX intake manifold features a three-piece design with large 58mm diameter runners versus the OEM diameter of 56 mm. A close-up of the RX manifold’s unique design shows symmetrical left and right surge tanks that are divided into three sections with a larger intake manifold.

The R35 RX cast-aluminum intake manifold delivers an increase in power throughout the mid- to high-rpm range. The secret is behind the manifold’s unique design. Engineered to equalize inlet airflow more evenly to each cylinder for maximum efficiency and performance, it’s an important feature when attempting to extract maximum power from any high-horsepower vehicle.

The manifold features internal velocity stacks built into the centersection. The “trumpet” style horns are engineered within the manifold on each runner to smooth the airflow going into the engine and maximize airflow rates entering the induction system.

The side-by-side comparison of flow simulation analysis between the Greddy versus OEM manifold shows how the RX35 unit enables air to be evenly distributed to each cylinder. Notice how the OEM manifold image to the right with its inefficient design passes an uneven amount of air through the ports.

The Greddy RX intake manifold is compatible with both the factory throttle bodies and the new big-bore billet Greddy RX throttle body kit. Although the manifold throttle inlet is manufactured for factory throttle bodies, it can easily be enlarged to accommodate the bigger RX throttle bodies. We should note that larger-sized Greddy throttle bodies will move the throttle bodies farther out from the factory location, which requires some minor modifications to the inlet charge pipes.

Greddy RX Billet Throttle Bodies

Until now, tuners were forced to rely on boring their OEM throttle bodies, allowing for only minimal airflow improvements. The RX throttle bodies are precision CNC engineered from billet aluminum and designed specifically to work with the factory drive-by-wire VR-series engines.

Greddy RX throttle bodies feature a large 75mm bore, which aids in delivering additional air for significant horsepower gains throughout the powerband. The throttle body specifications include an inlet diameter of 75 mm, butterfly valve of 68 mm, and an inlet to intake manifold diameter measuring 70 mm.

We tested the RX manifold with a pair of big-bore, billet Greddy RX throttle bodies on the SP Engineering/HDM GT-R and were rewarded with big gains. The manifold and throttle body combination was dyno proven in producing additional power throughout the powerband on the Nissan R35’s 3.8L VR38DETT twin-turbo V-6 with gains as much as 75 hp and 63 lb-ft of torque over the OEM components.