Honda J37a4 Engine Specs And Performance

If you’re looking for detailed technical information on a specific V6 powerplant, you’ve come to the right place. This article covers the essential Honda J37A4 engine specs and performance in a clear, straightforward manner.

The J37A4 is a 3.7-liter V6 engine produced by Honda for use in several of their larger vehicles. It represents a significant step up in displacement and power from the more common J35 series. Known for its smooth operation and robust power delivery, this engine has earned a reputation for reliability and performance.

We’ll break down everything you need to know, from its basic architecture to its real-world driving characteristics.

Fundamental Design and Architecture

The Honda J37A4 is part of Honda’s J-Series engine family, which has been a cornerstone of their lineup for decades. This particular variant features several key design elements that differentiate it.

Engine Type: 60-degree V6, SOHC (Single Overhead Camshaft) per bank.
Displacement: 3,664 cc (3.7 liters). This is achieved with a larger bore and stroke compared to the 3.5L versions.
Cylinder Block: Made from cast aluminum with reinforced silicone sleeves for durability.
Cylinder Head: Aluminum alloy, featuring Honda’s VTEC (Variable Valve Timing and Lift Electronic Control) system.
Valvetrain: 24-valve (4 valves per cylinder), with VTEC on both the intake and exhaust camshafts.
Fuel System: Programmed Fuel Injection (PGM-FI), which is Honda’s term for multi-point electronic fuel injection.

Detailed Technical Specifications

Here are the precise numbers that define the J37A4’s capabilities. These figures are crucial for understanding its potential and for comparison with other engines.

Bore x Stroke: 90.0 mm x 96.0 mm. The relatively long stroke contributes to its strong low-end torque.
Compression Ratio: 11.2:1. This is a high compression ratio for a naturally aspirated engine, requiring premium fuel (91 octane or higher) for optimal performance and to prevent knocking.
Horsepower: 300 hp @ 6,300 rpm (for most applications, like the Acura TL SH-AWD). Specific output can vary slightly by model year and vehicle.
Torque: 270 lb-ft @ 4,500 rpm. This healthy torque figure is felt across the rev range, especialy in mid-range acceleration.
Redline: 6,800 rpm. The engine remains smooth and willing even as it approaches this limit.
Engine Management: Honda PGM-FI ECU with Drive-by-Wire throttle control.

Key Performance Technologies

Honda employed several advanced technologies to get this level of power and efficiency from a naturally aspirated V6.

Dual-Stage Intake Manifold (DBW): Uses a butterfly valve system to switch between a long, torque-optimized intake path and a short, power-optimized path at higher RPMs.
Advanced VTEC System: Unlike some earlier VTEC engines that only affected intake valves, the J37A4’s system adjusts timing and lift on both intake and exhaust valves. This improves power across the entire rev band and enhances emissions control.
Variable Volume Intake System: Works in tandem with the dual-stage manifold to optimize airflow for different engine loads and speeds.
Friction-Reducing Measures: Includes roller rocker arms and low-tension piston rings to reduce internal mechanical losses, improving both power output and fuel economy.

Vehicles Featuring the J37A4 Engine

This engine was not used in a wide range of vehicles, making it somewhat special. It was primarily reserved for higher-performance or top-trim models.

Acura TL (4th Generation, 2009-2014): Specifically in the SH-AWD (Super Handling All-Wheel Drive) models. This is the most common application.
Acura RL (2009-2012): Used in the later years of the third-generation RL, paired with SH-AWD.
Honda Inspire (Japanese Market): Some variants of this model, sold in Japan, were equipped with the J37A4.

It’s important to note that the similar J37A1 and J37A2 engines were used in the Honda Pilot and Acura MDX, but these were tuned differently for SUV applications, with less horsepower and more focus on low-end torque.

Real-World Performance and Driving Feel

On paper, the specs are impressive, but how does it actually feel to drive a car with this engine? Owners and reviewers often highlight a few key characteristics.

The power delivery is exceptionally linear. Thanks to VTEC and the intake systems, there isn’t a dramatic “kick” at a certain RPM—instead, it pulls strongly from around 2,500 rpm all the way to the redline. The engine is remarkably smooth and refined, with minimal vibration even under hard acceleration.

Paired with the SH-AWD system in the TL, it provides confident power out of corners. The engine’s willingness to rev and its crisp throttle response make it engaging for spirited driving. It’s a mature performance engine that feels both powerful and polished.

Fuel Economy and Efficiency

For a 3.7L V6 producing 300 horsepower, the J37A4 is relatively efficient, though it’s not a fuel-sipper by modern standards. Expect real-world figures in the range of:

City Driving: 17-19 MPG
Highway Driving: 25-27 MPG
Combined Average: 20-22 MPG

Remember, using premium fuel is not just a recommendation; it’s required for the engine to operate correctly with its high compression ratio. Using lower-octane fuel can cause pre-ignition (knocking), reduce power, and potentially lead to long-term engine damage.

Reliability, Common Issues, and Maintenance

Overall, the J37A4 is considered a very reliable engine. It shares the robust design principles of the entire J-Series family. However, like any complex mechanical device, it has a few known areas to watch.

Common Maintenance Items

Spark Plugs: Use only the specified iridium-tipped plugs. Replacement is recommended around 100,000 miles but can be a labor-intensive job due to the rear bank’s location.
Timing Belt: The J37A4 uses a timing belt, not a chain. Honda recommends replacement every 105,000 miles or 7 years. This is a critical service—if the belt breaks, it will cause catastrophic engine damage.
Water Pump: Often replaced preventatively during the timing belt service, as it is driven by the timing belt.
Variable Valve Timing (VVT) Solenoids: Can sometimes fail or get clogged with sludge, leading to check engine lights (often P0341, P0344) and rough operation. Cleaning or replacement is usually the fix.

Potential Issues to Monitor

Oil Consumption: Some owners report higher-than-normal oil consumption, particularly in engines that have seen extended use with lower-octane fuel or infrequent oil changes. Regular monitoring of oil level is advised.
Exhaust Manifold Cracks: There have been isolated reports of the exhaust manifolds developing cracks, leading to an exhaust leak noise. This seems to be more prevalent in colder climates with significant heating/cooling cycles.
Secondary Air Injection System: This emissions-related system can fail (a common issue on many Hondas/Acuras of this era), triggering a check engine light. Codes P0411 or P0418 are typical.

Proactive maintenance is the key to longevity. Using full synthetic oil and changing it every 5,000-7,500 miles, along with adhering to all other service intervals, will help this engine last well over 200,000 miles.

Modification and Tuning Potential

The J37A4 responds well to basic bolt-on modifications, though its naturally aspirated design means large power gains require significant investment.

Intake and Exhaust: A cold air intake and a freer-flowing exhaust system can liberate a small amount of horsepower (typically 10-15 hp) and improve throttle response and sound.
ECU Tuning: Aftermarket tuning (via Hondata FlashPro or similar) can optimize ignition timing, fuel maps, and VTEC engagement points. This is where the most noticeable gains from bolt-ons are realized, potentially adding 20-30 hp at the wheels.
Forced Induction: Supercharger or turbocharger kits are available but are complex and expensive. They can, however, push power outputs over 400-450 hp reliably with proper supporting modifications and tuning.
Internal Work: The engine’s internals are quite strong from the factory. For high-horsepower forced induction builds, upgrading pistons and connecting rods is recommended.

It’s worth noting that the 6-speed automatic transmission in the TL SH-AWD is robust but has its limits. Significant power increases may necessitate upgrading the transmission’s clutch packs or valve body.

Comparison to Related Engines

How does the J37A4 stack up against its siblings?

vs. J35Y1 (e.g., in newer Pilots/Odysseys): The J35Y1 is a 3.5L with Earth Dreams technology, direct injection, and a higher 11.5:1 compression. It makes similar horsepower (around 280-290 hp) but with better fuel economy and more low-end torque. The J37A4 feels more performance-oriented and loves to rev higher.
vs. J35A8 (in older Acura TL): The older 3.5L makes about 280 hp. The J37A4’s extra 0.2L of displacement and updated tech provide a noticeable bump in torque and a broader powerband.
vs. J37A1 (in Honda Pilot): The SUV-tuned J37A1 produces only 250 hp and 250 lb-ft, optimized for low-end grunt and towing rather than high-RPM power. The camshafts and tuning are different.

FAQ Section

What is the horsepower of the J37A4 engine?

The Honda J37A4 engine produces 300 horsepower at 6,300 rpm in its primary Acura TL SH-AWD application.

Is the Honda J37A4 a reliable engine?

Yes, it is generally considered very reliable. Following the strict maintenance schedule, particularly for the timing belt and using premium fuel, is essential for ensuring its long-term durability. Some minor issues like VVT solenoid failures can occur but are usually not major.

What cars have the J37A4 motor?

The main applications are the 2009-2014 Acura TL SH-AWD and the 2009-2012 Acura RL. It was also available in some Japanese-market Honda Inspire models.

Does the J37A4 require premium gas?

Absolutely. With an 11.2:1 compression ratio, the engine is designed for 91 octane fuel or higher. Using regular fuel can cause knocking, reduce performance, and potentionally harm the engine over time.

What is the difference between J37A1 and J37A4?

The J37A1 is tuned for SUV use (Honda Pilot, Acura MDX), making less power (250 hp) and more low-end torque. The J37A4 has different camshafts, a higher state of tune, and intake components aimed at high-RPM performance for sedans.

How much torque does a J37A4 have?

It produces 270 lb-ft of torque at 4,500 rpm. This provides strong acceleration across a wide range of engine speeds.

Final Thoughts

The Honda J37A4 engine is a standout in the company’s history of excellent V6 designs. It combines smooth, refined operation with genuine performance, offering 300 horsepower in a linear, accessible way. While it demands proper care—specifically premium fuel and timely timing belt changes—it rewards owners with robust reliability and an engaging driving experience.

Whether you’re considering buying a vehicle equipped with one, or you already own one and want to understand it better, the J37A4 remains a compelling piece of engineering that represents the peak of Honda’s naturally aspirated V6 development. Its specs and performance continue to impress enthusiasts and everyday drivers alike.