Looks, lux and lighting: loaded '05 Acura RL features an all-wheel-drive system could be the benchmark for luxury performance sedans

Automotive Industries,  Nov, 2004  by Rob Wilson

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The RL, as in Acura RL, must stand for "Really Loaded," because it really is. Them simply are no factory options whatsoever on the new '05 and the standard equipment is so comprehensive and the systems so sophisticated it seems every need is provided for or exceeded. Buying this automobile is pretty much an open and shut case of pick your color and pony up the MSRP of $48,900.

Real-time traffic for 20 of the largest U.S. metropolitan centers, XM Satellite radio, OnStar (one year standard), navigation system with voice recognition, hands-free telephone interface, GPS linked solar sensing, dual-zone, duN-mode automatic climate control system, Bose 10-speaker surround sound with 6-disc CD, DVD-Audio and DTS changer, keyless access and starting system, active noise cancellation: all standard comfort and convenience features and this only touches on a few of the higher tech bells and whistles on the ,'05 RL.

This is a much sleeker automobile than the old Acura RL, just inches shorter, slightly wider, but much, much wilder. Through its evolution from concept car to production automobile, the new RE has retained its wedge- like shape with forward sloping beltline and short deck lid. It achieves a very attractive yet powerful, aggressive look and stance.

The new RE is longer and wider than its competition in the sector, claims Acura, and has significantly wider front and rear track. It sits on 17 in. alloy wheals and Michelin tires.

If Acura has taken some of the fun out of buying a car, it has certainly reinvested that fun into driving the new '05 RL. The 3.5 L 24-valve VTEC V6, rated 300 hp at 6,200 rpm, packs 75 hp more than the previous 3.5 L RL powerplant. Acura attributes the gains to a new dual-stage, high inertia intake manifold (+15 hp), higher internal engine efficiencies and lower pumping losses (+40 hp) and a variable flow-rate exhaust system (+ 20 hp). The engine is fitted with variable valve timing and lift electronic control (VTEC), with 4 valve per cylinder, belt-driven, single overhead camshaft.

Peak torque for the engine is 260 lb.ft. at 5,000 which is redlined at 6,800 rpm. Bore and stroke is 3.5 in x 3.66 in. (89 mm x 93 mm). The engine has a relatively high compression ratio of 11.0:1, which compares with 9.6:1 for the previous 3.5 L RL powerplant.

The new engine has a forged steal crankshaft with revised counterweights to handle the greater weight of the higher compression pistons. These have taller reinforced crowns. Pistons are oil jet cooled on the underside. Connecting rods are made of forged steel, with the big end split by fracturing, providing for a perfect bearing cap fit.

The engine is of 60 degree V configuration, with a heat-treated die-cast aluminum alloy block with cast-in centrifugally cast-iron liners. Cylinder heads, also of aluminum, incorporate the tuned exhaust manifolds as an integral part of the casting.

The VTEC system operates the intake valves in two modes to optimize volumetric efficiency and complete combustion of the air-fuel mixture. The intake valves have low lift and are open for a comparatively short duration at low engine speed. The intake valves switch to a high lift, longer duration mod to provide optimal volumetric efficiency at higher engine speed where breathing is more critical. The engine shifts modes at 4,950 rpm and it is absolutely seamless to the driver.

By using a three-rocker valve actuation, each intake valve is controlled by its own low-speed cam lobe. This is what permits the staggered valve lift and opening duration.

At 4,950 rpm, the powertrain control module opens an electric spool valve routing pressutized oil to small pistons in the intake valve rocker arms. Sliding into position in all six cylinders, the pistons lock together the three intake rockers which then provides the high-lift, long-duration cam lobe valve actuation.

Tuned intake is provided by a two-piece, dual-stage intake manifold. This serves to boost torque across the full operating range of the engine. The volume of the manifold's plenum is tuned to resonance together with the length of the inlet passages to amplify intake pressure waves thereby assisting charge, air filling of each cylinder.

At 4,000 rpm, the engine control opens two butterfly valves, one for each cylinder bank, and this interconnects the two halves of the plenum, effectively tuning them for resonance at the higher engine speed range where even more charge-air is required.

The direct-injection engine also features detonation/knock control retarding ignition timing to eliminate knock--of damaging potential in this high compression engine. So-called Programmed Fuel Injection (PGM-FI) monitors the exact state of exhaust gas and multiple engine inputs to optimize the amount of furl injected to each cylinder.

A drive-by-wire throttle adjusts the moment-to-moment relationship between pedal position and throttle opening and changes the amount of "gain" between the pedal and butterfly. Engine response is smooth and progressive. The gain increases at higher speed for crisp passing and hill climbing.