J-series Lives On
Honda's J-series V6 made its debut over 10 years ago on the 1996 Acura 3.0CL. Since then, it has been Acura's sole V6 engine family.
The 3.2L J32 served as the TL's standard engine between 1999-2008. For 2009, the base engine is now the 3.5L, and Acura's 3.7L J37 (Acura's biggest) powers the 2009 TL SH-AWD.
3.5L SOHC VTEC V6
A 3.5L was introduced to the TL lineup with the 2007 TL Type-S - this configuration produced 286hp and 256lb-ft. The 2009 J35 is essentially the same engine that was found in the TL Type-S, but there are a few differences, resulting in slightly less output in the '09 version (280hp and 254lb-ft). Compression has actually increased from 11.0:1 to 11.2:1, but for duty in the Base TL, there's less of an emphasis on all-out performance, so this year's J35 uses more conservative intake and exhaust tuning for NVH performance. For this engine, Honda's more traditional SOHC VTEC valvetrain has been employed. This system switches between two discrete camshaft profiles to alter the timing and lift of the intake valves, depending upon RPM.
3.7L SOHC VTEC V6 with Intake/Exhaust SOHC VTEC
The TL SH-AWD's 3.7L SOHC VTEC engine is an enhanced version of the all-new-for 2009 3.7L V6 that was recently introduced in the RL. Compared to the RL's new V6, the TL version is up 5hp and 2lb-ft, for a total of 305hp and 273lb-ft.
This engine is essentially a bored and stroked version of the 3.5L, but there are some key differences, starting with the cylinder liners. The 3.5L engine features an aluminum block with cast-in iron cylinder liners, but due to the relatively close bore spacing of the J-series V6 design, the 3.7L version uses high-silicon aluminum cylinder liners for improved cooling. During the block machining process, a mechanical etching process exposes silicon particles embedded within the aluminum sleeves, creating a hard piston ring sealing surface. A side benefit of the aluminum cylinder liners is that the overall engine weight of the J37 is actually less than the J35.
The really big news for this engine family in 2009 is the introduction of VTEC control for both intake and exhaust valves. This is made possible by a new multi-arm VTEC® rocker arm system for the exhaust valves.
For each cylinder (set of 4 valves), the camshaft has 6 lobes. The two center lobes (in the set of 6) actuate the intake valves - one lobe is the "high cam" lobe and the other is the "low cam" lobe. There are two exhaust lobes outside of these two center lobes. The outermost lobes are the exhaust "high cam" lobes, and the lobes closer to the center lobes are the "low cam" lobes. For each cylinder, there are a total of 4 exhaust followers and 2 intake followers, each one dedicated to a single cam lobe.
At engine speeds below 4700 rpms, the three "high cam" followers are decoupled from the valve rocker arms, while the "low cam" followers are actuating the 4 valves. Above 4700 RPM, under the correct conditions, the engine control computer signals VTEC® actuation, sending oil pressure to three locking pins, which couple the rocker arms to the "high cam" followers. This increases the lift and duration of both the intake and exhaust valves (+28% lift, +35% duration on the intake side, and +10% lift, +11% duration on the exhaust side). With this new intake/exhaust VTEC® system, more valve timing control is possible, resulting in 47 percent more valve overlap over the standard intake-only VTEC® system.
This added valve control results in improved torque production, improved emissions, more top end power, and better fuel efficiency. Additionally, the new VTEC system also uses roller cam followers, resulting in improved durability and reduced friction.
Stopping is important too
Back in 2004, the addition of Brembo brakes on 6-speed TL models was huge news. Acura and Honda have long been known for equipping their vehicles with undersized brakes, so going with a big name like Brembo brought a lot of performance credibility to the 6MT TL. Interestingly, Acura has abandoned the Brembo brakes for 2009, but the new no-name stoppers are said to represent a significant improvement.
Acura's not messing around with the size of the new braking hardware. 12.6" rotors are found up front, bound by dual piston calipers, while 13.1" rotors (a full 2" larger than before!) are clamped by single piston calipers in the rear. Stopping force is is improved dramatically as brake pad area has increased by 21% up front and 22% in the rear. SH-AWD models use the same hardware, but performance is enhanced by way of functional front fascia-mounted cooling ducts and "proprietary vacuum booster specifications". Additionally, 2009 TL SH-AWD models feature Hill-Start Assist (HSA, also found on 2009 Honda Pilot), to eliminate vehicle rollback when starting on a sloped surface.
The 2009 joins its platform siblings (2008 Accord and 2009 TSX) in utilizing Honda's new unit-body frame rail system. Stamped steel frame rails are positioned above and inside the floorpan (rather than underneath it) to create a nearly flat underside. The benefits include improved structural strength (for improved crash performance), reduced air turbulence (improving aerodynamics and reducing wind noise), and an improvement in interior space.