Radium Engineering Toyota MK5 Supra Port Injection Kit: Unlocking the True Potential of the B58

The MK5 Supra has quickly become one of the most tuner-friendly platforms on the market. With the BMW-sourced B58 engine at its core, it offers strength, reliability, and big power potential right out of the gate. But as with most factory turbocharged setups, once you start pushing boost levels beyond what the OEM fuel system was designed for, fueling becomes the limiting factor.

That’s where the Radium Engineering Toyota MK5 Supra Port Injection Kit comes in. Built for enthusiasts and tuners looking to safely squeeze every ounce of performance from their B58 builds, this system provides precise additional fueling exactly where it’s needed—directly into the intake runners.

Whether you’re chasing a reliable 600–700whp street setup, or you’re pushing north of 1,000hp with a big turbo and E85, Radium’s port injection kit is the clean, reliable solution that bridges the gap between what the stock fuel system can handle and what your build actually demands.

Why Port Injection Matters on the B58

The Supra’s B58 engine uses direct injection (DI) from the factory. DI systems are excellent for efficiency, emissions, and throttle response—but they have their limits. At higher horsepower levels, the factory DI injectors and high-pressure pump simply can’t deliver the volume of fuel needed to keep up with increased boost or ethanol-based fuels.

Port injection solves this problem. By spraying fuel into the intake runners upstream of the intake valves, it supplements the direct injection system with additional fuel volume. The result?

• Increased fueling headroom for high-boost applications

• Better fuel atomization and cylinder distribution

• Cooler intake valves (helping combat carbon buildup common in DI-only engines)

• Improved throttle response and smoother power delivery

This dual-fueling approach is becoming the standard for modern high-power turbocharged engines, and Radium’s kit makes it straightforward on the B58.

Radium Engineering: Why Their Kit Stands Out

There are plenty of ways to add supplemental fueling to the B58, but not all solutions are created equal. Radium Engineering is known for building high-quality fuel delivery systems designed to integrate cleanly with modern platforms. Their MK5 Supra port injection kit offers:

1. Factory-Style Fitment:
   The injector plate mounts neatly between the intake manifold and the cylinder head. No cutting, hacking, or questionable adapters.

2. Injector Flexibility:
   Injectors are sold separately, allowing you (and your tuner) to spec the right injectors for your build, whether that’s 1,000cc, 1,300cc, or even 2,000cc.

3. Precision Machining:
   CNC-machined from billet aluminum, the injector plate maintains airtight seals and perfect alignment, ensuring reliability under boost.

4. High-Quality Materials:
   Built with components that can withstand the heat and pressure of high-performance use, from ethanol fuels to long track sessions.

5. Expandability:
   Designed to integrate seamlessly with Radium’s full lineup of fuel rails, regulators, and ancillary parts for a complete fueling upgrade path.

Breaking Down the Kit

The Radium Toyota MK5 Supra Port Injection Kit includes:

• Injector mounting plate (CNC-machined billet)

• Necessary hardware for installation

• Seals to prevent boost leaks and ensure OEM-like fitment

Fuel injectors are not included. This gives flexibility, allowing you to select injectors sized for your goals and fuel type.

Radium also offers complementary components such as:

• Fuel rails with AN fittings

• Fuel pressure regulators

• Fuel pumps and surge tanks

• Fittings and lines designed for ethanol compatibility

Installation Overview

While this isn’t a step-by-step guide, here’s what’s involved when installing the Radium kit:

1. Manifold Removal:
   The intake manifold must be pulled from the engine to install the injector plate.

2. Injector Plate Install:
   The plate is sandwiched between the manifold and cylinder head with proper seals to prevent boost leaks.

3. Fuel Rail & Injectors:
   Injectors are mounted into the plate via Radium’s rail system. Lines and fittings are routed to tie into your fuel system.

4. ECU Integration:
   A standalone ECU, piggyback, or port injection controller (like AIC-1 or similar) is required to properly manage injector operation. This allows your tuner to dial in additional fueling under load.

Installation is straightforward for an experienced shop, but does require proper tools, fuel line routing knowledge, and tuning.

Why It’s Essential for High-Performance Builds

Here’s where this kit really shines:

• E85 Conversions: Ethanol requires ~30% more fuel volume than pump gas. Port injection provides that headroom.

• Big Turbo Kits: Once you move past the factory turbo, DI alone can’t keep up with the airflow.

• Track & Drift Cars: Consistency under heat and load is critical. Supplemental fueling prevents lean conditions and detonation.

• Street Builds: Even at moderate power levels, port injection improves throttle response, smoothness, and long-term reliability.

Without port injection, tuners are forced to rely on band-aid solutions like higher-pressure DI pumps or meth injection. While those have their place, Radium’s port injection kit is the long-term, scalable solution.

Why Radium Engineering?

Plenty of brands offer fueling solutions, but Radium has earned a reputation for:

• Motorsport-grade durability

• Clean, factory-style fitment

• Compatibility with ethanol and high-pressure applications

• Technical support and expandability

When you’re investing in something as critical as fueling, you don’t want to risk a cut-corner part. Radium’s products are designed to be part of a complete fueling ecosystem, not just a one-off solution.

Supporting Mods to Consider

The port injection kit is just one part of the fueling puzzle. Depending on your power goals, you may also need:

• Upgraded Fuel Pumps: High-flow low-pressure pumps and surge tanks keep injectors fed at all times.

• Fuel Lines and Regulators: AN fittings and ethanol-safe lines prevent restrictions and leaks.

• ECU or Controller: A proper standalone or controller is required to manage the supplemental injectors.

• Injectors: Select size based on horsepower goals and fuel type. Your tuner will guide you here.

Who Should Run This Kit?

• Street Enthusiasts looking for smooth, reliable fueling on E85 or with mild turbo upgrades.

• Track Day Drivers who want consistent fueling under heat and sustained high RPM.

• Drag Racers & Time Attack Builds pushing the B58 into four-digit horsepower territory.

• Tuners & Builders who want a scalable, reliable fueling solution that integrates cleanly.

Final Thoughts

The Radium Engineering Toyota MK5 Supra Port Injection Kit is more than just an upgrade—it’s a necessity for anyone serious about pushing the limits of the B58 engine. By adding supplemental fueling exactly where it’s needed, this kit ensures you have the headroom, consistency, and reliability required for high-performance builds.

From street-driven cars running ethanol to track monsters chasing 1,000+ horsepower, this kit unlocks the full potential of the Supra while keeping installation clean and straightforward. Combine it with Radium’s ecosystem of fuel components, and you’ve got a fueling system built to handle whatever power goals you’re chasing.

👉 Ready to take your B58 to the next level? Order the Radium Engineering Port Injection Kit for your Toyota MK5 Supra from Select Speed Shop →