A45 Turbo Upgrade: Making the Jump to Pure Turbos 2.2L Hybrid Power

If you own a Mercedes-AMG A45 and have been chasing higher power figures, the stock turbocharger eventually becomes the limiting factor. The Pure Turbos 2.2L Hybrid upgrade has become a go-to solution for enthusiasts who want substantial, reliable gains without stepping into a full built-block or custom fabrication territory. This upgrade replaces the factory turbo unit with a hybrid design that flows significantly more air while retaining a direct bolt-on fitment. In this guide, we cover everything from the engineering behind the hybrid to installation procedures, tuning requirements, and the real-world performance you can expect.

What the Pure Turbos 2.2L Hybrid Brings to the Table

The Pure Turbos 2.2L Hybrid is not a generic remanufactured unit. It uses a billet compressor wheel, upgraded bearing system, and revised turbine geometry engineered specifically for the M260 and M139 engine platforms found in the A45, CLA45, and GLA45 models. The "2.2L" designation refers to the increased compressor wheel diameter, which allows the turbo to move a greater mass of air compared to the stock unit. This directly translates to higher boost potential across the rev range without sacrificing spool characteristics.

Key engineering highlights include:

  • A CNC-machined billet compressor wheel that improves flow efficiency and reduces rotating mass.
  • A larger, ported compressor housing that reduces inlet restriction and allows higher volume airflow.
  • Reinforced thrust bearings and upgraded journal or ball bearing options depending on the specific kit version.
  • Direct bolt-on compatibility with the factory manifold, downpipe, and charge piping, requiring no custom fabrication.

The hybrid nature of this turbo means it retains the original turbine housing and manifold interface, so installation does not require removing the manifold or dealing with separate turbo and manifold alignment. This is a critical advantage over full-frame aftermarket turbo kits that often require extensive modifications to the engine bay.

Why the Stock Turbo Falls Short

The factory turbocharger on the A45 is capable and responsive, but it was designed with a balance of performance, emissions, and durability targets set by Mercedes-AMG. For enthusiasts running software tunes, the stock turbo quickly reaches its aerodynamic limit. At boost levels above 28-30 psi, the stock compressor wheel becomes inefficient, generating excessive heat and requiring the engine to pull timing. The Pure Turbos 2.2L Hybrid addresses this by providing a higher flow ceiling, allowing the engine to maintain lower intake temperatures at elevated boost pressures. This means more consistent power delivery during sustained pulls and track driving.

Another limitation of the stock unit is its bearing system. Under sustained high boost and high RPM operation, the factory bearings can experience accelerated wear. The upgraded bearing system in the Pure Turbos hybrid provides additional durability for enthusiasts who frequently drive at the limit.

Installation Preparation: What You Need Before You Start

Proper preparation saves hours of frustration during a turbo swap. While the Pure Turbos unit is a direct bolt-on, the process still requires access to tight spaces in the engine bay, dealing with exhaust hardware, and handling coolant and oil lines. Here is a comprehensive list of what you should have ready.

Tools and Equipment

  • Metric socket set with extensions, including 10mm, 13mm, 15mm, and 18mm sockets.
  • Torque wrench capable of reading in both lb-ft and Nm.
  • Ratchet with flexible head or universal joint for hard-to-reach bolts.
  • Pickle fork or ball joint separator for any exhaust bracket connections.
  • Coolant catch pan and clean container for oil.
  • Vacuum bleeder for coolant refill if available.
  • O2 sensor socket if you need to remove the downstream sensor.
  • Penetrating oil for rusted exhaust fasteners.
  • New gaskets: turbo-to-manifold gasket, turbo-to-downpipe gasket, and any O-rings for oil and coolant lines.
  • New crush washers for oil feed and return lines.
  • Anti-seize compound for exhaust bolts.

Fluids and Consumables

  • Engine oil meeting Mercedes-Benz specification 229.52 or 229.71, with the correct viscosity for your climate.
  • Coolant concentrate or pre-mix meeting MB 325.0 specification.
  • Brake cleaner for degreasing surfaces before reassembly.
  • Shop towels and gloves.

Safety Precautions

Work in a well-ventilated area. The engine bay will be hot if the vehicle was recently driven, so allow the engine to cool completely before starting. Disconnect the negative battery terminal to prevent electrical shorts and to avoid activating the fuel pump accidentally. Wear safety glasses when working with spring clamps or when cleaning components with solvent. If you are lifting the vehicle, use jack stands rated for the weight and never rely solely on a hydraulic jack.

Step-by-Step Installation Guide

This guide assumes you have basic mechanical experience and access to a lift or a safe jacking setup. The process is outlined for the M260 engine, but the steps are similar for the M139.

Step 1: Battery Disconnection and Access Preparation

Disconnect the negative terminal and move the battery cable aside. Remove the engine cover and any trim panels that obstruct access to the turbocharger area. On the A45, this typically includes removing the air intake ducting, the air box, and the charge air cooler inlet pipe. Label any vacuum lines or electrical connectors you disconnect.

Step 2: Drain Fluids

Drain the engine oil and coolant to prevent spills when disconnecting the turbo lines. You can drain the coolant from the radiator petcock and the oil from the drain plug. Reinstall the drain plugs after draining to keep contaminants out.

Step 3: Remove the Stock Turbocharger

Start by loosening the V-band clamp connecting the turbo to the downpipe. It may be seized, so apply penetrating oil and let it soak. Remove the downpipe support bracket and the O2 sensor. Next, disconnect the oil feed line from the top of the turbo and the oil return line from the bottom. The coolant lines are next; be prepared for residual fluid. Remove the turbo inlet pipe and the charge pipe from the compressor outlet. Finally, unbolt the turbo from the exhaust manifold. There are typically four bolts securing the turbo to the manifold. Carefully lift the turbo out of the engine bay. It helps to have a second pair of hands due to the weight and tight clearance.

Step 4: Prepare the New Turbo for Installation

Inspect the Pure Turbos 2.2L Hybrid for any shipping damage. Prime the turbo by pouring a small amount of clean engine oil into the oil feed port and rotating the compressor wheel by hand. This ensures the bearings are lubricated before the first start. Install the new gaskets on the manifold and downpipe flanges. Apply a light coat of anti-seize to all threaded fasteners.

Step 5: Install the Pure Turbos Hybrid

Position the new turbo onto the manifold studs. Tighten the manifold bolts in a crisscross pattern to the manufacturer's torque specification. Reconnect the oil feed line with a new crush washer, then reconnect the oil return line. Install the coolant lines with new O-rings. Reattach the downpipe V-band clamp and tighten it to the specified torque. Reinstall the O2 sensor. Connect the turbo inlet pipe and the charge pipe, ensuring all clamps are tight and seated properly. Double-check that no tools or loose items are left in the engine bay.

Step 6: Refill Fluids and Reassemble

Refill the engine oil and coolant following the correct bleeding procedure for the cooling system. Reinstall the air intake ducting, air box, and engine cover. Reconnect the battery.

Step 7: Initial Start and Leak Check

Start the engine and let it idle. Check for oil leaks at the feed and return lines. Check for coolant leaks at the coolant line connections. Listen for any unusual noises from the turbo area. Let the engine reach operating temperature and verify that the cooling fans cycle on. If everything looks good, take a short test drive at low load to confirm the turbo is operating normally.

Tuning and Calibration: Unlocking the Full Potential

Installing the Pure Turbos 2.2L Hybrid without a proper tune is not recommended. The increased airflow capacity will cause the engine to run lean if the factory fuel maps are not adjusted. Lean operation leads to detonation, high exhaust gas temperatures, and potential engine damage. A dedicated calibration is essential.

Choosing a Tuner

Work with a tuner who has experience with the M260 or M139 engine and the Pure Turbos hybrid. Many reputable shops offer remote tuning via ECU flashing tools. Look for tuners who provide data logging support and revisions as part of the package. Dyno tuning is ideal, but street tuning with proper data logging can also yield excellent results.

What the Tune Adjusts

  • Boost pressure targets: The tune will raise boost levels to take advantage of the hybrid's flow capacity, typically targeting 30-35 psi peak.
  • Fuel mapping: Injector pulse width and fuel pressure are adjusted to maintain target air-fuel ratios across the load range.
  • Ignition timing: Timing is optimized for the increased cylinder pressure without inducing knock.
  • Throttle mapping: Many tuners sharpen throttle response to match the turbo's improved spool.
  • Limiter adjustments: Rev limiters and speed limiters may be raised or removed depending on your goals.

Data Logging and Monitoring

After tuning, monitor key parameters during your first few drives: boost pressure, air-fuel ratio, intake air temperature, coolant temperature, and knock sensor activity. A wideband O2 sensor is highly recommended for accurate air-fuel ratio readings. Log data during a third-gear pull from 2500 RPM to redline and review it for any anomalies.

Performance Expectations: Real-World Gains

The Pure Turbos 2.2L Hybrid delivers a noticeable power increase that transforms the driving character of the A45. The gains are not just peak numbers; the power band broadens significantly.

Horsepower and Torque

With a proper tune and supporting mods such as a high-flow downpipe and upgraded intercooler, expect peak horsepower gains of 60-90 HP over a stage 1 tune on the stock turbo. Torque gains are equally impressive, with increases of 70-110 lb-ft. Some setups have achieved over 450 HP at the wheels on pump fuel, with higher figures on ethanol blends or race gas.

Spool Characteristics

One concern with larger turbos is lag. The Pure Turbos 2.2L Hybrid retains excellent spool characteristics due to its turbine-side design. Full boost typically arrives by 3500-3800 RPM, only slightly later than the stock turbo. Below 3000 RPM, there is a minor trade-off in responsiveness, but the mid-range and top-end pull more than compensates.

Acceleration and Track Performance

The broader power band means fewer gear changes are needed to stay in the sweet spot on a track. Exit speeds from corners improve, and the car feels significantly stronger at higher speeds where the stock turbo runs out of breath. Quarter-mile times typically drop by 0.4 to 0.7 seconds with proper traction.

Supporting Modifications for Maximum Reliability

To fully support the additional airflow and power, consider these complementary upgrades:

  • High-flow catalytic converter or catless downpipe: Reduces exhaust backpressure and allows the turbo to spool more freely.
  • Upgraded intercooler: Keeps intake air temperatures in check during sustained boost, preventing power loss due to heat soak.
  • Cold air intake: Provides a less restrictive path for the turbo to draw air, improving throttle response and peak power.
  • Upgraded fuel system: Depending on the power target, you may need larger fuel injectors and a higher-flowing low-pressure fuel pump.
  • Engine oil cooler: Track use generates higher oil temperatures; an upgraded cooler helps maintain oil viscosity and protection.

Common Pitfalls and Troubleshooting

Even with a well-designed kit, issues can arise during or after installation. Here are the most common problems and how to address them.

Oil Leaks at the Feed or Return Lines

Oil leaks are usually caused by damaged O-rings, improperly torqued fittings, or reuse of old crush washers. Always use new sealing components. If a leak persists, inspect the line for cracks or deformation.

Boost Leaks

A boost leak will cause low power and sluggish response. Check all charge pipe connections, the turbo inlet, and the intercooler coupling. Perform a boost leak test using a pressure tester if necessary.

Check Engine Light After Installation

The check engine light often illuminates due to an O2 sensor that was damaged during removal or a vacuum line that was left disconnected. Scan the fault codes and address the root cause. If the code is related to the catalyst, a tune with catalyst delete logic may be required.

Coolant Loss

If coolant levels drop after the first few drives, verify that the cooling system was properly bled. Air pockets can cause erratic temperature readings and coolant loss. Use a vacuum filler tool to purge air from the system.

Maintenance Considerations After the Upgrade

The Pure Turbos 2.2L Hybrid is built with higher-grade components than the stock turbo, but it still requires proper maintenance to deliver long service life.

  • Use high-quality synthetic oil and change it at shorter intervals, especially if the car is driven hard. Every 3,000 to 4,000 miles is recommended for tracked cars.
  • Allow the turbo to cool down after a hard run before shutting off the engine. A turbo timer can help, but a 30-60 second idle period is sufficient.
  • Inspect the turbo inlet and air filter regularly for debris that could damage the compressor wheel.
  • Check charge pipe connections for tightness periodically, as thermal cycling can loosen clamps over time.

Final Thoughts

Upgrading your A45 turbo to the Pure Turbos 2.2L Hybrid is one of the most effective bolt-on modifications available for this platform. It delivers a substantial and reliable increase in power, broadens the torque curve, and transforms the driving experience without requiring permanent modifications to the vehicle. The key to success lies in careful installation, a professional calibration, and attention to supporting systems. With those elements in place, you will have a car that pulls harder than many purpose-built track machines while remaining daily-driver friendly. For more detailed specifications and ordering information, visit the Pure Turbos website. For tuning solutions, consult with a reputable shop such as Eurocharged or Weistec Engineering, both of which have extensive experience with Mercedes-AMG platforms.