Body Overview

Near-luxury sedan buyers have always loved the previous Acura TL for its performance and handling. They also love their build quality, durability and resale value when the time comes to trade in. For the 2005 TL, the designers chose to "step outside the box" to provide TL customers with a daringly more emotional and athletic design.

Design Concept

The TL was designed to embody aggressiveness and power, agility and endurance. Designers began with the stance of the vehicle-how it looks and sits on its suspension. They worked towards a look of poise, with a promise of agility and power. The contrast of muscular tension and fluid lines flows through the sheet metal, with the long wheelbase, short front and rear overhangs and wide track setting the tone.

The design team leaders were, in part, influenced by "Bauhaus" styling themes. Founded in 1919, Bauhaus was the first and most famous German design house. Bauhaus set a template for European design with the now-famous maxim, "Form follows function." That classic design logic meshes well with established Acura design philosophies.

An excellent example of this fresh design sense is in the dynamic "face" of the TL, with its strong character and reduced body openings. An under-bumper cooling air system makes this look possible because most of the cooling air is drawn in beneath the front fascia.

The 2005 Acura TL design features in review:

Front

• Aggressive front end
• Wide stance
• Short, dramatic bumper offset
• Raked windshield
• Strong style lines at the outer edges of the hood

Side

• Minimal wheel arch to tire distance
• Concave style line links front and rear marker lights
• Integrated body color door handles

Rear

• Wide stance
• High, short deck lid
• Short dramatic bumper offset
• Wide roof span for wider moonroof and improved head clearance
• Efficient trunk room
• LED taillights
• Reduced gap between exhaust finishers and rear valance

Packaging

The Acura TL is 3.6 inches shorter, 1.9 inches wider and 3 inches taller than the previous generation TL.

Rigidity

Adding stiffness to a vehicle's unit body improves road holding and makes the driver feel more connected to the car, but it also can add weight. In the 2005 TL, ample use of high strength steel accounts for a strong unit body structure that is also light. A front shock tower brace, a rigid front bulkhead, a roof stiffener that extends to the C-pillar, and a parcel shelf box section also contribute to stiffness. Optimized attachment of the front frame rails, roof and rear panel and parcel shelf and larger rear unit body gussets also contribute to overall stiffness.

High-Tensile Steel

High-tensile 440 and 590 steel was used for 48 percent of the body. Even though the forming process is similar to that used for standard steel, the chemical composition of high-tensile steel allows it to be stronger after forming. Parts can therefore be made thinner and lighter while maintaining strength.

Aerodynamics

Design and engineering objectives for the TL required aerodynamic creativity. The challenge was to allow stylists to craft the TL front end as powerfully and emotionally as they wanted, without impeding the airflow essential for engine operation. Moreover crash safety, high-speed stability, reduced wind noise and high fuel mileage were essential.

Achieving the desired exterior styling required that most of the cooling air come from under the front of the car. Several different polypropylene panels enhance underbody aerodynamic performance. These lightweight and durable panels include a curved valance below the front fascia. Air attaches to its smooth radius at highway speeds and is directed into the radiator. The center section of the valance bends out of the way if the TL encounters a curb or other obstruction.

Other aerodynamic elements include refined A-pillar shape, front and rear deflectors, an engine undercover and a rear floor cover. These underbody improvements benefit fuel economy, reduce wind noise and improve high-speed stability. Internal testing reveals that the 2005 TL betters the BMW 530i, Mercedes-Benz C320, Lexus ES 300 and Volvo S60 in coefficient of drag.

Reduced Wheel Arch Gaps

Minimizing the visual gap between the edges of the tires and the wheel arches was an important design goal. To retain a wide wheel track with these narrow gaps, the TL has a special fender flange design that allows the tires to sweep up and inside without making contact during suspension movement.

Mass Reduction

Keeping the TL curb weight low was a matter of the highest priority for Acura. Despite a comprehensive array of technology and the use of insulating materials to promote an even quieter and more luxurious cabin, strict control over component weight has kept the TL to just 3,575 pounds, with the 6-speed model coming in at only 3,482 pounds.

Power Glass Moonroof

The TL has a 30.7 inch moonroof, the largest Acura has ever developed. It lends a tremendous open feeling to the car, and features the convenience of 1-touch opening and closing, and an anti-pinch safety feature, the first for an Acura moonroof.

The overhang of the edge into the opening is a scant 1.6 inches. The moonroof itself is virtually flush, reducing the chance of wind noise. There is also a special flush type seal that promotes quietness.

HID (High-Intensity Discharge) Headlights

LED Lighting

Extensive use of Light Emitting Diodes (LEDs) provides a high-tech image for side and rear lighting. LEDs are used for the front side marker lights, Center High Mount Stop Lamp (CHMSL), taillights, and rear side marker lights.

These LED arrays provide uniform lighting and a unique, modern look. They also have a quicker turn-on time and a projected service life four times longer than normal automotive bulbs.

5 MPH Bumpers

The Acura TL uses a highly efficient Xenoy thermoplastic energy absorber with a high-strength steel reinforcement beam that absorbs 80 percent of low-speed crash energy. This allowed designers to reduce the overhang of the bumper, while also reducing the weight and repair costs. Both the front and rear bumpers meet the federal government's damage-free regulation when tested at 5 mph. They are also lighter than previous versions: the weight savings are 3.0 pounds and 2.9 pounds front and rear, respectively.

Noise, Vibration & Harshness (NVH) Control
An assortment of anti-NVH measures includes advanced aerodynamic design, the first U.S.-market use of automotive acoustic glass with shade band, insulating panels under the hood and inside the trunk and the fenders.

Key NVH countermeasure areas include:

Acoustically tuned glass windshield

To reduce cabin noise, the TL windshield is made of 4.7 mm thick acoustic glass, which consists of two layers of safety glass, separated by a thin acoustic resin center. This represents the first time that acoustic glass with a shade band has been applied to a luxury vehicle in North America. The windshield reduces road noise on smooth asphalt significantly in the higher frequency ranges. To reduce noise intrusion through the side glass, the front and rear movable door glass is 5 mm thick.

Thinsulate

Patented by 3M, Thinsulate^TM insulation was developed for thermal applications but it is also ideal for noise reduction. It is crushable and can be used in tight-clearance areas. In the TL it is used behind the door liners, rear seat side garnishes, center console, rear seatback and front and rear pillar garnishes. It is also used under the instrument panel and parcel tray.

Trunk

Engineers treated the trunk as an acoustic package, containing the speaker array and trunk hinges and springs in a rigid box structure. This improves audio bass performance, reduces interior noise levels, enhances the appearance of the trunk interior, and reduces the chance that belongings will be damaged by a speaker or hinge.
VH reduction item

• Aluminum-alloy front subframe
• Improved melt sheet package
• Improved A-pillar shape
• Diffuser type mirrors with full seals
• 5 mm side glass
• Hood insulator
• Improved door-handle sealing
• Flush-mount moonroof

Aluminum-alloy front subframe
Besides its low mass, the TL aluminum-alloy front subframe reduces "starting boom" (resonance noise) without the use of additional dampers.

Melt Sheet
The careful application of high-density melt sheet makes a huge reduction in high-frequency sound. Testing results show it reduces the high frequency (approx. 500Hz and above) vibration of the TL floor panels, decreasing noise inside the vehicle.

Power Windows

TheTL has a front power window feature with an auto-open and auto-close feature. It also incorporates an anti-pinch safety feature. The glass is 5 mm thick to reduce cabin noise.

Exterior (SIDEVIEW) Mirrors

A mirror housing needs to be small and aerodynamic to reduce turbulence-without compromising mirror area. To reduce the housing size engineers devised a way to hold the mirror element from behind instead of at the sides, and carefully controlled the gap between the mirror element and housing to further reduce turbulence. Blue-tinted mirrors also reduce eyestrain in bright conditions.

Engineers also measured the airflow through the channel between the A-pillar and the mirror. By designing this channel in an expanding V-shape, the air actually decelerates (rather than accelerates) as it moves across the glass. This helps keep the air from tumbling across the side glass, reducing high- and mid-frequency noise.

Engineers also positioned the mirrors forward, away from the window glass, to further reduce wind noise while increasing the driver's side view. A reverse tilt function automatically tilts either the left or right mirror down when the TL transmission is shifted into Reverse. This is a driver-selectable function that may be turned on or off as desired.

Doors & Latches

To resist parking lot dings and dents, the TL door skins are made from special 340H high-tensile steel. This bake-hardened steel has much greater resistance to bending and a higher work-hardening threshold than conventional steel, making the door skins much more resistant to dents and dings. The door skins are 10 to 15 percent stronger with 50 percent better permanent deform resistance than conventional steel.

Door fit is a matter of extraordinary precision on the TL. The gap is just 3.5 mm at the leading edge of the front doors, 4 mm between the doors, and 3.5 mm at the trailing edge of the rear doors.

Acura precisely refined the door closing sound on the TL. A door sash structure, manufactured with a laser-welded blank, increases the rigidity of the door sashes and reduces objectionable high frequency noise as the doors are closed. A door lock structure absorbs sounds caused by the latch, eliminating objectionable noise.

Body Trim

The TL's aggressive and sporty styling is subtly enhanced by satin trim on the leading edge of the hood, on the grille, and above the license plate. The B-pillar and drip moldings are high gloss black, while aluminum step garnishes inside the door openings provide a finished appearance.

Exhaust Finishers

The exhaust has bright trapezoidal finisher tips integrated into the rear styling. The tips are inset far enough to allow adequate bumper stroke in the event of a slow-speed collision, but are positioned far enough back to allow exhaust gases to pass beyond the bumper. Special multi-axis rubber mounts control the exhaust tip placement, allowing a closer fit of the rear bumper fascia. The gap is approximately 0.8 inch, compared to a gap of nearly 1.2 inches on the previous TL. A high heat-resistance polypropylene garnish is clipped to the bumper to protect it from heat.

Exterior Paint

The 2005 TL is available in eight pearl and three metallic exterior colors. The painting process begins when the steel body receives a phosphate bath to completely clean it of oils and film after welding is complete. This is followed by an electrodeposition primer bath, where the unit body is electrically charged to attract the primer. After baking, the color coat is applied, followed by a protective clear coat.

Accessories

The TL has a wide range of exterior accessories available through Acura dealers. They are factory warranted for 4 years/50,000 miles when purchased with the vehicle.

Individual exterior accessories include:

• 18-inch aluminum-alloy wheels
• Back-up sensor
• Bodyside protectors
• Car cover
• Decklid spoiler
• Door edge guards
• Door window visor
• Engine block heater
• Front and rear splash guards
• Front under spoiler
• Gold emblem kit
• Moonroof visor
• Nose mask
• Rear under spoiler
• Spoiler wing
• Sports shocks and springs
• Wheel locks

These accessories are also available in these packages:

Aero Kit - Includes front, side and rear under body spoilers

Protection Package - Includes wheel locks, splashguards and trunk tray

Wheel Package - Includes 18-inch aluminum-alloy wheels and tires

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