Installing a turbocharger kit on an Infiniti G37 transforms its naturally aspirated VQ37VHR engine into a forced-induction powerhouse, but it demands careful planning and precise execution. You'll unlock substantial horsepower gains, but success relies heavily on understanding your fuel system limits, cooling capacity, and engine management parameters from the start.
Understanding VQ37VHR Turbo Limitations
The factory VQ37VHR engine features an open-deck aluminum block and high compression ratios, typically around 11:1. That high compression ratio makes for crisp throttle response in stock form, but it leaves very little room for error once boost enters the equation.
Stock connecting rods and pistons on the VQ37VHR have established limits. Most experienced tuners agree that pushing past 450 to 500 wheel horsepower on a stock bottom end puts immense stress on the factory internals, particularly the thin connecting rods. If you're planning to run high boost pressures exceeding 9 PSI on pump gas, building the engine with forged rods and low-compression pistons becomes essential for long-term reliability.
Selecting Your Turbo Kit Components
Choosing the right turbocharger kit dictates how your G37 delivers power. Single turbo kits and twin turbo kits each offer distinct characteristics. As reported in latest coverage by Reuters, the effects are notable.
- Single Turbo Kits: Typically spool slightly later in the rpm band due to longer piping routing, but they often produce massive top-end power and simplify exhaust packaging under the hood.
- Twin Turbo Kits: Offer quicker spool times and broader power bands by mounting smaller turbos closer to each exhaust manifold, though installation is tighter and more complex.
Look for kits featuring ball-bearing turbochargers for improved transient response over traditional journal-bearing units. Turbine A/R sizing also matters; a smaller A/R housing spools faster for street driving, while a larger A/R housing prevents backpressure bottlenecks at high rpm.
Fuel System Upgrades and Management
Stock fuel injectors and the factory fuel pump cannot support the increased air volume provided by a turbocharger. Starving a turbocharged engine of fuel causes severe lean conditions, leading to instant detonation and catastrophic engine failure.
- Fuel Injectors: Upgrade to high-flow injectors rated between 650cc and 1000cc depending on your power goals and whether you plan to run E85 ethanol blends.
- Fuel Pumps: Install a high-flow in-tank fuel pump, such as a 345LPH or 450LPH unit, to maintain steady fuel pressure under heavy boost.
- Engine Management: You'll need a robust tuning platform. Custom ECU calibration via EcuTek Technologies allows your tuner to safely rewrite ignition timing, fuel maps, and boost control solenoids.
Step-by-Step Installation Process
Tackling a turbo kit installation requires an organized garage, specialized tools, and mechanical experience. Expect the project to take anywhere from 20 to 40 hours of labor.
- Disconnect Battery and Drain Fluids: Disconnect the negative battery terminal, then drain the engine coolant and engine oil completely to prepare for turbo manifold and oil line installation.
- Remove Factory Exhaust and Intake: Unbolt the factory exhaust manifolds, catalytic converters, and air intake assembly. Keep track of all oxygen sensors and hardware.
- Install Oil Feed and Return Lines: Tap the oil pan for the turbocharger oil return line, ensuring the fitting sits above the oil level to prevent pooling. Route the oil feed line from a pressurized oil source on the block.
- Mount Turbochargers and Manifolds: Bolt up the aftermarket exhaust manifolds and secure the turbochargers. Ensure proper clearance around steering shafts, coolant hoses, and the firewall.
- Install Intercooler and Piping: Mount the front-mount intercooler securely to the crash bar, then route the aluminum charge piping from the turbos to the intercooler and up to the throttle bodies. Tighten all T-bolt clamps to prevent boost leaks.
- Reassemble and Test: Refill all fluids, reconnect sensors, and double-check every hose clamp and electrical connection before attempting an initial crank.
Common Installation Mistakes to Avoid
Avoiding typical installation pitfalls saves you from costly engine repairs and endless troubleshooting sessions.
- Improper Oil Drain Angle: If the oil return line slopes upward or sits below the oil level in the pan, oil will back up into the turbo center housing, blowing past the seals and causing heavy smoke from the exhaust.
- Ignoring Boost Leaks: Even a tiny gap in your intercooler piping causes unmetered air loss, forcing the turbo to work harder and triggering rich or lean diagnostic codes. Pressure test your charge pipes before driving.
- Skipping Oil Priming: After installing new turbos, crank the engine with the fuel pump fuse pulled until the oil pressure light turns off. This ensures oil reaches the turbo bearings before high-rpm rotation begins.
Frequently Asked Questions
How much horsepower can a stock G37 engine handle with a turbo kit?
A healthy stock VQ37VHR engine can reliably handle around 400 to 450 wheel horsepower on a conservative tune. Pushing past 500 wheel horsepower requires upgraded connecting rods, pistons, and head studs.
Do I need to upgrade my transmission for a turbo G37?
If your G37 has a manual transmission, the factory clutch will slip immediately under boost and needs an upgraded multi-disc or heavy-duty clutch kit. Automatic 7-speed transmissions can handle stock turbo power levels for a while, but high-horsepower builds require upgraded valve bodies or built transmission internals.
What kind of maintenance changes after turbocharging?
You'll need to change your engine oil much more frequently—typically every 3,000 miles—using high-quality full synthetic oil. Spark plugs should also be gapped tighter and replaced more often to prevent spark blowout under boost.
Can I run a turbo kit on pump gas?
Yes, premium 91 or 93 octane pump gas works well for moderate boost levels. However, if you want to push higher boost safely without detonation, mixing in E85 or running a dedicated flex-fuel tune yields significantly higher power output.
