Engineering Performance: The '07 Acura TL Type-S
The greatest success for Acura is unquestionably the TL sport sedan (that’s as in “touring luxury”), which it originally introduced in 1996, and which was completely modified in model year 2004. The TL is the leading seller in the company’s lineup: from January through August 2006, 48,940 TLs were sold; the MDX sport utility came in second, with 33,377 products during the same period. According to John South, a planner within the Acura Product Planning department, before the redesigned and reengineered TL was launched, the TL buyer was someone who was primarily looking for a vehicle offering safety, comfort, performance, value, DQR and (dependability, quality, reliability). Style was optional. But with the more aggressively designed ’04 model, the balance shifted from the logical assessment to something with an increase in emotional content.
Still, there was one vehicle that had been in the TL lineup, but which was absent from the ’04 platform: the Type-S, the performance variant of the model. So in addition to providing a mid-cycle refresh for the TL with such differences as a larger satin chrome grille, separate fog lights, mirrors with LED turn signals, a three-spoke steering wheel, new headrests, blue ambient lighting for the footwell and the console, new aluminum door trim, and even a new engine cover, they decided to bring back the Type-S after a three-year absence.
Certainly, there are some distinctive design differences between the standard TL and the Type-S. Like a rear spoiler. Black chrome grille at the front and black chrome license plate surround at the rear. A more pronounced splitter in the front fascia. Quad exhaust. Red illumination rather than blue. Stainless steel pedals. A leather and carbon-fiber shift knob. Paddle shifters for the automatic transmission version. Bigger bolsters on the seats. Type-S logos. Yes, a number of small things that are meant to make the vehicle appear more aggro. Something to really appeal to the emotional buyer, one looking for performance.
Performance, of course, isn’t a matter of logos. It’s predicated on engineering—the powertrain, in particular.
Yes, there is different engine cover for the Type-S. With a red stripe and reversed type on the aluminum displacement plate. But the more significant aspect is what’s under the cover. While the TL has a 3.2-liter, SOHC all-aluminum engine that produces 258 SAE Net hp @ 6,200 rpm and 233 lb-ft of torque @ 5,000 rpm, the Acura engineers have based the engine for the Type-S on the 3.5-liter used in the Acura RL sedan, the top-of-the-line model in the lineup. This engine produces 286 hp @ 6,200 rpm and 256 lb-ft of torque @ 5,000 rpm. Brian Hourt, test principle engineer on the program, explains how you go from 258 hp to 286 hp:
- 18 hp through the displacement increase
- 6 hp from an exhaust flow increase, going from 128 liters/sec to 146; a low-restriction catalyst is used on the Type-S
- 4 hp from an intake flow increase, going from 150 liters/sec to 156; there is an increase in the diameter of the intake valves, and in the VTEC (Variable Valve Timing and Lift Electronic Control) setup there is an increase in the valve timing lift and duration.
As weight was a consideration, they worked to make the engines lighter for both vehicles. Overall, it is 6.7 kg lighter than the engine in the ’06 TL. Among the ways this was accomplished:
- Cylinder head covers: Magnesium is used in place of aluminum. A 30% weight save.
- Intake manifold: Magnesium. A 53% weight save.
- Camshaft: A hollow shaft upon which the cams are fitted is used. An 11% weight save.
- Oil strainer: From a stamping to a plastic molding. A 40% weight save.
While the TL is available with an all-new five-speed automatic with Sequential SportShift, based on the transmission that debuted in the ’05 RL (note the architecture sharing being followed here), the Type-S is available with either the automatic or a close-ratio six-speed manual. Once again, weight savings was a goal. The manual has a high-pressure die-cast aluminum alloy housing. Special narrow high-strength steel gears are used, and the shafts are hollow. Overall, the six-speed is lighter than the automatic. Overall, a Type-S with the manual weighs just 3,559 lb., while the automatic version weighs 3,674. One consequence of the new five-speed and the new 3.5-liter V6 is a redesign of the subframe. The U-shaped aluminum alloy component is hydroformed and attached to aluminum alloy corner brackets.
What does this get you? In internal tests of acceleration—0 to 60 mph, quarter mile, and 50 to 75 mph—against both an Infiniti G35 and BMW 330, the Type-S, especially with the manual transmission, handily outperformed both. Hourt admits that one of the goals of the program was to assume leadership in performance, so would one expect anything else?
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