The Infiniti G37 Fuel Economy Improvement Guide: Save Money at the Pump
You’re cruising down the highway in your G37, enjoying that powerful VQ37VHR engine purr, but when you glance at the fuel gauge, you realize this performance comes at a cost — here’s how to squeeze every mile out of every gallon without sacrificing the driving experience you love.
TL;DR
The Infiniti G37 averages about 10.5L/100km combined (approximately 22-23 MPG), with urban driving dropping to around 15.3L/100km (15 MPG) and highway improving to roughly 7.8L/100km (30 MPG) . Improving fuel economy involves a combination of regular maintenance like tune-ups and spark plug replacements, upgrading to performance parts like cold air intakes that can improve MPG, adjusting driving habits, and even considering a flex fuel conversion for potential cost savings — though E85 typically reduces MPG .
Key Takeaways
- Regular tune-ups can bring power back to your G37’s engine and improve fuel economy — watch for signs like reduced MPG or shaky idling
- Cold air intake upgrades from brands like STILLEN claim improved mileage per gallon along with performance gains of 14WHP and 6.9WTQ
- Smooth driving habits make a real difference — hard starts and stops increase stress on engine parts and reduce fuel economy
- Spark plugs should be replaced around every 30,000 miles to maintain optimal engine performance and efficiency
- E85 flex fuel conversion offers cheaper fuel costs and performance benefits, but expect reduced MPG compared to gasoline
- Fuel system cleaning removes varnish and carbon deposits that hurt your G37’s efficiency
Understanding Your G37’s Fuel Economy
The VQ37VHR Engine: Power and Efficiency Potential
The heart of your G37 is the 3.7-liter VQ37VHR engine, which produces an impressive 330 horsepower and 270 lb-ft of torque . What makes this engine special is Nissan’s VVEL (Variable Valve Event and Lift) technology, which works similarly to BMW’s Valvetronic system .
Here’s the interesting part — VVEL eliminates the need for a traditional throttle butterfly, improving both the torque curve and fuel consumption across the rev range . The system combines hydraulic-controlled variable valve timing with electronically controlled variable valve lift on the intake side, which helps improve emissions and fuel efficiency . In fact, the G37 was estimated to achieve nearly one MPG better than the G35 Sedan and nearly two MPG better than the previous generation G35 Coupe .
Official Fuel Economy Figures
Based on 2013 G37 specifications, here’s what you can expect:
- Combined fuel consumption: 10.5L/100km (approximately 22-23 MPG)
- Urban driving: 15.3L/100km (approximately 15 MPG)
- Extra-urban (highway): 7.8L/100km (approximately 30 MPG)
- Fuel tank capacity: 80 liters
- Recommended fuel: Premium ULP with 95 RON octane
Practical Ways to Improve Your G37’s Fuel Economy
1. Regular Tune-Ups and Maintenance
A well-maintained engine is a more efficient engine. Here’s what the experts recommend:
Spark Plug Replacement: Replace spark plugs on time — about every 30,000 miles or so . Worn spark plugs can prevent your car from starting properly and reduce fuel efficiency .
Fuel System Cleaning: Over time, varnish, dirt, and carbon deposits build up inside your fuel injectors, throttle body, and throttle plate. A professional fuel system cleaning removes these deposits, improving your fuel system’s performance . Watch for signs like:
- Shaky idling
- Poor fuel economy
- Knocking noises from the engine
Air Filter Replacement: Your engine needs clean air to run efficiently. A clogged air filter restricts airflow, forcing your engine to work harder and use more fuel.
2. Upgrade to a Cold Air Intake
One of the most popular modifications for the G37 is upgrading to a cold air intake system. The STILLEN Gen 3 Dual Ultra Long Tube Air Intake is specifically designed for the VQ37 engine and offers several benefits:
- Improved MPG: The manufacturer claims improved mileage per gallon
- Performance gains: Up to 14WHP and 6.9WTQ
- Increased airflow: Larger surface area air filters provide superior airflow
- Better throttle response: More responsive acceleration
Key considerations:
- Installation is described as “driveway-friendly” and straightforward
- No tune or reprogramming is needed — it runs great on the OEM tune without triggering check engine lights
- Available in both dry and oiled filter versions
- Some models require mild modification of the core support for installation
The idea is simple — your engine needs air to burn fuel. The factory air box is designed for quiet operation, which often means restricted airflow. A cold air intake allows more cold air to reach the engine, improving the air-to-fuel ratio, which leads to better gas mileage and performance .
3. Fuel System Upgrades and E85 Conversion
For owners looking for a more significant change, E85 flex fuel conversion is an option worth considering.
What is E85 Conversion? An eFlexFuel kit converts your G37’s VQ37VHR engine to run on both E85 and regular gasoline .
Benefits:
- Cost savings: E85 fuel prices are generally lower than regular gasoline
- Performance boost: Higher octane levels in E85 can lead to increased horsepower and improved throttle response
- Environmental benefits: Ethanol burns cleaner, reducing greenhouse gas emissions
Important drawbacks to consider:
- Fuel economy reduction: E85 typically reduces miles per gallon compared to gasoline
- Fuel availability: E85 stations may not be as widespread as regular gas stations
- Need for proper tuning: Running E85 without a proper tune can lead to suboptimal performance and potential engine damage
“The eFlexFuel kit offers a seamless, plug-and-play solution for converting your vehicle to run on E85. Our kits offer a seamless, plug-and-play solution for converting your vehicle to run on E85.”
4. Driving Habits That Save Fuel
Your right foot has the biggest impact on fuel economy:
Smooth Starts and Stops: Hard starts and stops can increase stress on engine parts and reduce fuel economy. Using gradual, smooth starts and stops is a great way to help your engine run better and maximize fuel efficiency .
Maintain Steady Speeds: Constant acceleration and deceleration burns more fuel. Use cruise control when appropriate on highways.
Avoid Excessive Idling: The G37’s 80-liter tank gives you good range, but idling wastes fuel without moving you anywhere.
Keep Tires Properly Inflated: Under-inflated tires increase rolling resistance, forcing your engine to work harder.
Remove Excess Weight: Extra weight means extra fuel consumption. Clear out unnecessary items from your trunk and cabin.
5. Proper Fuel Selection
The G37 requires Premium ULP with 95 RON octane . Using lower-octane fuel can cause engine knocking, reduced performance, and potentially lower fuel economy as the engine computer adjusts timing to compensate.
Comparison of Fuel-Saving Upgrades
Here’s a quick comparison of options to improve your G37’s fuel economy:
| Upgrade Type | Best For | Installation Difficulty | Approximate Cost | Fuel Economy Impact |
|---|---|---|---|---|
| Regular Tune-Up | Maintenance-minded owners | Professional recommended | $200-500 | Restores lost efficiency |
| Cold Air Intake | DIY enthusiasts wanting performance + MPG | Moderate (driveway-friendly) | $400-650 | Claimed improvement |
| Fuel System Cleaning | Owners noticing reduced performance | Professional service | $100-200 | Removes deposits hurting efficiency |
| E85 Conversion Kit | Owners wanting cheaper fuel costs | Moderate to advanced | $500-800+ | Improved cost per mile, but reduced MPG |
| Spark Plug Replacement | Preventative maintenance | Moderate | $100-300 | Prevents efficiency loss |
The VVEL Advantage: How Your G37 Already Saves Fuel
One thing to appreciate — your G37 already has built-in fuel-saving technology. The VVEL system is estimated to deliver:
- 32% quicker response than comparable systems
- 20% smaller design and 52% fewer parts than BMW’s Valvetronic
- Improved fuel consumption at both top and low rev ranges
This means the G37 is designed to be as efficient as possible for a 330-horsepower V6. Any additional improvements come from smart maintenance and driving habits.
Frequently Asked Questions
How often should I replace spark plugs in my G37?
Replace spark plugs on time, or about every 30,000 miles. Old spark plugs can reduce fuel economy and prevent your car from starting at all .
Does a cold air intake really improve MPG?
Manufacturers like STILLEN claim their G37 air intake systems improve mileage per gallon by increasing airflow and improving the air-to-fuel ratio . Many owners report noticeable improvements in throttle response and efficiency .
Can my G37 run on E85?
Yes, with an E85 conversion kit from companies like eFlexFuel, your VQ37VHR engine can run on both E85 and regular gasoline. However, running E85 without a proper tune is not recommended .
Does E85 improve fuel economy?
No — E85 typically reduces miles per gallon compared to gasoline . However, the lower cost per gallon can still result in overall savings at the pump.
What’s the best way to improve G37 fuel economy?
Regular maintenance (tune-ups, spark plugs, fuel system cleaning), upgrading to a cold air intake, and adopting smooth driving habits. Avoid hard starts and stops, which increase stress on engine parts and reduce fuel economy .
What fuel should I use in my G37?
Your G37 requires Premium ULP with 95 RON octane. Using lower-octane fuel can cause knocking and potentially reduce performance and efficiency .
What are signs my G37 needs a tune-up?
Watch for shaky idling, poor fuel economy, knocking noises from the engine, or a lit check engine light. These signs indicate it’s time for engine service .
References
Sources and Further Reading:
- Firestone Complete Auto Care – G37 Tune-Up Guide
- STILLEN – G37 Gen 3 Air Intake System
- eFlexFuel – G37 E85 Conversion Guide
- Drive.com.au – 2013 Infiniti G37 Specifications
What fuel-saving tricks have worked best for your G37? Have you tried a cold air intake or E85 conversion? Share your experience in the comments below — your insight could help another owner save money at the pump.