DOMESTICS! The 2007 domestic car nameplate lineup has HERE COME THE

Transcription

1 HERE COME THE 2007 DOMESTICS! BY PAUL WEISSLER The domestic manufacturers have several new passenger vehicle offerings on tap for 2007, as well as significant advances in the areas of performance, economy, convenience and comfort. The 2007 domestic car nameplate lineup has important new entries from General Motors, Ford and Chrysler. Yes, there are conventional sedans such as the Saturn Aura and Chrysler Sebring, a new Mustang muscle car (the Shelby GT500) and a two-seat convertible (the Saturn Sky). But most significant are the crossovers carlike vehicles with transverse front-drive, optional all-wheel-drive and SUV cues. You know such domestic entries as GM s Saturn VUE, Buick Rendezvous, Chevy Equinox and HHR and Pontiac Torrent, Chrysler s PT Cruiser and Ford s Freestyle. This model year, look for a GM trio GMC Acadia/Buick Enclave/Saturn Outlook along with Ford s Edge and Lincoln MKX, plus the Jeep Compass from the Chrysler Group. The following offerings from the domestic carmakers are truly new and noteworthy: 26 November 2006

2 Chrysler Sebring Ford Edge Saturn Sky Jeep Compass Shelby GT500 Buick Enclave November

3 This engine compartment view of the Saturn Green Line shows electronics that control the mild hybrid powertrain to the right. In the spring, it will be optionally available in the Saturn Aura sedan. Note the blue wiring harness, which indicates medium-voltage electronics. The conventional 12-volt leadacid battery for cold starts and accessories is just underneath. General Motors Much of GM s new-car product news is about Saturn. Saturn has three new vehicles the Aura sedan, Sky convertible and Outlook, which joins VUE in the crossover category. However, some of the powertrain changes made for Saturn also apply to other GM makes. The most important new car coming out of the GM camp may be the Saturn Aura. Although it s built on the same platform as the Chevy Malibu and Pontiac G6, it s much more upscale nicer interior, more elegant overall appearance, quieter. It s almost like the separation between the Lexus ES 350 and the Camry V6, although not quite as far apart. As for GM engines, the 3.5L V6 is the base Aura engine (a step up from the base 2.4L four-cylinder in the Malibu and G6). This pushrod engine gets variable valve timing, joining the 3.9L V6 used in the Malibu, G6 and Impala/Monte Carlo. The 3.9 V6, incidentally, also gets Active Fuel Management (which deactivates three cylinders during cruise), introduced last year on the Impala/Monte Carlo 5.3 V8. The 3.6L world V6 (DOHC and variable intake and exhaust valve timing), which was used in Cadillac and Buick models in 2006, is the top option in the Pontiac G6 and the Aura, and the only engine in the Acadia/Enclave/Outlook crossover vehicles. The 3.6 V6 is mated to a six-speed transaxle, the same basic transmission (with internal differences, though) that also is being used in the new Ford crossovers and Lincoln MKZ sedan. Ford and GM are in a joint venture to produce this gearbox. What about four-cylinder engines, the several versions of the Ecotec in particular? The 2.4 version continues as noted in the Malibu and G6 but with significant changes, the most visible of which is the dropping of the Photo: Paul Weissler What looks like a large alternator at the front of the Saturn mild hybrid Ecotec engine is actually a belt-driven starter-alternator system for automatic restarts. A conventional 12-volt starter performs cold starts. This is the twin-scroll turbo for the Ecotec 2.0L Four. Notice the diagonal split entry on the end of the pipe for the exhaust gases. It creates a twin path, one from cylinders 1 and 4, the other from 2 and 3. There s one path to each scroll, for the most efficient exhaust gas flow. The turbo mates to an exhaust manifold with a similar split. Photos courtesy Saturn 28 November 2006

4 engine oil cooler. GM added piston oil jets and modified the cooling system, which lowered oil temperatures enough to eliminate the need for external oil cooling. The 2.0 Supercharged version continues in the Saturn Red Line and Chevy Cobalt SS. The 2.2, with what GM calls continuous improvement upgrades, continues in the Cobalt, Malibu, G5 (a new Pontiac-badged twin to the Cobalt) and Saturn ION. Changes to the 2.2, however, include such visually noticeable, service-related ones as a cartridge oil filter replacing the spin-on type and coil-on-plug ignition replacing the dual-coil cassettes with plug wires. A special premium version of the 2.4 Ecotec also goes into the Saturn VUE Green Line and (some time in the spring) the new Aura as a low-cost mild hybrid that promises a fuel economy boost of up to 20%. What s a mild hybrid? Well, the GM hybrid pickups that came out last year are an example. They use a flywheel alternator/starter system and 42-volt nickel-metal-hydride battery pack. The setup in the VUE, and that s coming to the Aura this spring, has a conventional starter plus what looks like an oversized alternator but is actually an alternator/starter with a That sure looks like the top of a dipstick on this Chrysler transmission, with a label that warns against use of anything but CVT fluid. But it s just a cap; the dipstick is actually a separate special tool from Miller. Photos: Paul Weissler very special, seven-rib-wide belt with a unique tensioner. A complex computer strategy determines when to stop the engine, typically when it s warmed up and the vehicle is stopped, such as at a traffic light. When the driver steps on the gas pedal, the alternator/starter operates as a motor, restarting the engine instantaneously. During acceleration, the motor also provides a small boost through the engine. During deceleration/braking, some of the energy goes to operate the alternator to charge the 42-volt battery pack; that s called regenerative braking. The battery pack is located behind the rear seat and has a fan and ductwork for cooling. All the electronics are housed in an underhood module, characterized by the blue wiring harness that indicates medium-voltage systems (vs. orange for high-voltage full hybrids). Like most electronics packs, this one runs pretty hot, so a tap off the front of the engine cooling system routes coolant through the electronics housing to lower temperatures. Accessories run on 12 volts and there s an auxiliary 12-volt lead-acid battery, which also operates a conventional starter for cold starts. The vehicle s onboard diagnostics cover the hybrid system and will log specific trouble codes. The mild hybrid won t run on electricity alone (full hybrids have battery packs many times the size) and it doesn t do nearly as much regenerative braking. But at perhaps 35% of the price premium of a full hybrid, it s more likely to pay for itself a lot The power transfer unit on Caliber/Compass all-wheeldrive models is bolted to the transaxle, as shown here. At the rear, the Caliber/Compass torque split coupling an electronically controlled multidisc clutch transfers torque according to signals from ABS wheel speed sensors. 30 November 2006

5 THE 2007 DOMESTICS! sooner and be a lot more affordable for buyers. A 2.0L direct-injection turbocharged version of the Ecotec is optional on GM s two low-volume two-seat convertibles, the Pontiac Solstice (GXP model) and a new Saturn spin-off, the Sky. This engine, which has a smaller bore and stroke than the 2.4 Four, is GM s first U.S. direct-injection engine. The turbo, a twin-scroll design, makes use of extreme valve overlap to allow intake air to help sweep out the exhaust at low rpm, spooling up the turbo to eliminate most of the usual acceleration lag. Because the fuel is injected C Main Shaft (2 Planetaries) Output Shaft (Added Planetary) directly into the cylinder, injection occurs after the exhaust has been swept out, so the intake air that goes with it contains no fuel. There s a new Dexron automatic transmission fluid No. 6, labeled Dexron VI. It is said to provide major improvements in clutch durability and friction stability, more consistent oil thickness and less foaming and oxidation. The recommended service interval for severe use is 50,000 miles; for socalled normal use, double that figure. Dexron VI actually came into use in 2006 production, and if a vehicle has it, don t use anything else. The new fluid can be retrofitted to 2005 models only, which requires flushing out the old Dexron III. Don t use D-VI on anything older than 2005, or on any Saturn VUE, whose transmissions take specific fluids. Remember, the VUE s tranny is a CVT (continuously variable transmission), which, as we note in our coverage of the Chrysler Group, requires a specific fluid. Ditto for the five-speed manual or Honda automatic also used in the VUE. GM s crossover vehicles the Acadia, Enclave and Outlook are a bit different from the totally carlike type in that they have a sheet metal ladder frame integrated into the underbody, onto which front and rear subframes Photo: Paul Weissler Chrysler s sixspeed automatic transaxle was developed from a four-speed by the installation of an additional planetary gearset and clutches on the output shaft, as shown. Power transfer is by sprockets with a chain drive at the back end of the transmission (C). are bolted. It s still a unit body vehicle, with the longitudinal frame rails of the conventional unit body and the addition of ladder steps connecting them. This integral frame does not perform the function of a conventional separate frame; rather, the ladder steps provide a major improvement in side-impact protection. There are front and rear subframes for powertrain and suspension. The transverse-mount 3.6L V6 was boosted from 270 to 275 hp, 251 ft.-lbs. of torque, with cylinder head modifications and new camshafts for this specific application. An optional electronically controlled multidisc clutch coupling provides all-wheel-drive with on-de- If the chart at right is missing, please circle #40 on the Product Information Card on page November 2006

6 mand, variable power split. Ground clearance is 7.4 in. Only the Acadia is out now; the Outlook is due in early spring, the Enclave by early summer. Photo: Paul Weissler Photo courtesy Ford Chrysler Group Why are we including a Jeep the new Compass in a car report? Doesn t it belong in our January light truck/suv roundup? Not this one, which, like the Caliber, is really a crossover a Jeep that isn t trail-rated, but is designed to get some extra business from people who like the Jeep image, never go offroad but just want to be able to go in snow. So the Compass was built on the same platform as the Dodge Caliber, but with a more rugged look and Jeep design cues. Although we covered Caliber in our 2006 report, since the arrival of the Compass, there s important additional information. The powertrain is the same 2.4L four-cylinder and JATCO CVT you ll find in the Caliber. With all the transmission fluids on the market, you won t be thrilled to know that this CVT requires a special oil. If it s the Mopar brand, it s CVTF+4 and it s dyed green. The CVT oil has to provide exceptional lubrication and not cause slippage when the pulley halves apply clamping pressure to the steel link belt. The changes in clamping pressure must be instantaneous, and avoiding slippage is critical, or the transmission would fail quickly. Naturally, Dodge and Jeep dealers will have the oil for openers. JATCO is a Nissan affiliate company that makes similar CVTs for Nissan products, such as the Murano crossover and the new Versa econocar. So, if necessary, you should be able to get the appropriate oil from Nissan dealers, too. You ll notice what appears to be a dipstick tube at the front of the vehicle on the driver s side, and it should have a warning label to use CVT oil. But when you remove the top, there s no stick. The dipstick itself is a special tool (Miller No. 9336). The stick is marked for fluid levels for different temperatures, although there is an acceptable range. If a customer asks about a bump-step close to wide-open-throttle when accelerating, you should know it s just a detent that separates the economy and performance modes of the CVT. Overriding the detent activates the performance mode. Both the Caliber and Compass have a four-wheel-drive system available, a pretty basic design with a power transfer unit on the transaxle at the front and an electronically controlled multidisc clutch to vary the power transfer according to readings off the antilock brake wheel speed sensors. The HVAC case for the Caliber has a special section at the glovebox that con- This is an external view of Ford s new 3.5L DOHC engine, called the Duratec 35. It develops 265 hp, a competitive output for the vehicles in which it s installed. It s shown with the six-speed Ford/GM joint venture transaxle attached. The supercharged 5.4L V8 on the Shelby GT500 with cast-iron block produces 500 hp to create an affordable supercar for the Mustang brand. November

7 centrates a/c system cold air into a beverage storage area. Called a Chill Zone, it requires the a/c to be on, of course. The Chrysler Pacifica gets a major mechanical fix-up for The problem was inadequate performance from the single overhead-cam 3.5L V6, which in the relatively heavy vehicle was unable to provide decent launch. Fuel economy was so-so and overall acceleration feel with the four-speed automatic was somewhat crude. The factory fixes were not accomplished with all-new components, but with intelligent upgrades to existing ones. The 3.5 V6 was stroked to 4.0L. Longer stroke equals more low-end torque and better launch. Although the block was always sized for the longer stroke, Chrysler did beef it up when it went to the new displacement. The 4.0 displacement adds just five horses (to 255) and just 15 ft.-lbs. of peak torque (to 265). But in the low-middle range, when most people feel it, the torque is as much as 35 ft.-lbs. greater. Externally, the engine looks the same, although the air intake has been slightly reshaped. It s still a three-stage design, though. The 3.5L version continues in the Chrysler 300, and is the top option in the all-new Chrysler Sebring sedan, where the transverse front-drive installation drops horsepower to 235 and torque to 232 ft.-lbs. The base engine on the Pacifica is the 3.8L pushrod V6, which, along with the 3.3 V6, also continues in use on minivans. All pushrod V6s are being changed over to a newly issued smaller oil filter. So for a while you ll see some with the larger filter, some with the smaller one. The Pacifica and the new Sebring with the 4.0 or 3.5L SOHC V6 will get Chrysler s new six-speed automatic transaxle. It s the same as the four-speed automatic, with an additional planetary gearset (and clutches) on the output shaft, which multiplies the number of gear ratios from the two planetary gearsets on the mainshaft. Chrysler doesn t use all of the possible ratios because there wouldn t be enough ratio separation to make it worthwhile. However, the upshift 4th gear is 1.45 and the kickdown 4th (6-4 shift) ratio is 1.57 for better acceleration, so there really are seven gears. The housing is basically the same as the four-speed, which continues in use on the Pacifica V6 pushrods and with the 2.4 Four and 2.7 V6 in the Sebring. The housing was modified to accommodate a new, more compact torque converter for The new Sebring is a stylish competitor for the Camry, Accord, Altima, Oil Cooler A stacked-plate engine oil cooler is installed on the supercharged 5.4L V8. Fusion, Malibu/G6 and Aura. With the Four and two V6s, it has one engine more than its Japanese competitors, and is a match for GM with the 2.4 Four and 3.5 and 3.6 V6s. The platform is all-new, and you can expect to see more Chrysler Group products based on it. A novel feature is a cup holder that contains a Peltier junction unit, a mini version of the electric pic- We took the cover off the black box on the right shock tower of the supercharged Shelby GT500 (see photo opposite page) and saw two relays and two fuses. One relay and fuse is for the supercharger s intercooler water pump, the other relay and fuse are for the electric fuel pump. Photo courtesy Ford 42 November 2006

8 Photos: Paul Weissler Photo courtesy Ford For stable handling of a vehicle with 500 horses, the Shelby GT500 has this underbody brace connecting the lower control arms rear bushing, aiding a conventional shock towers brace and beefy sway bars. nic coolers and heated and cooled car seats. This setup is totally independent of the HVAC, as are car seats. Ford The Lincoln MKZ sedan was introduced as the Zephyr last year, and it was just a trimmed-out version of the Ford Fusion/Mercury Milan. But the Zephyr name didn t last long, and for 2007 the MKZ replacement has an all-new 3.5L V6 and six-speed automatic. That same powertrain combo is being used in the Ford Edge and Lincoln MKX crossovers, which are built on a modified version of the platform also used for Fusion/Milan/MKZ sedans. Compared with the sedans, the wheelbase for the Edge and MKX is stretched 4 in. (to 111.2), although the overall length was reduced 4 in. (to 185.7). The body is 67.2 in. high, which is 10 in. taller than the sedans. These crossovers, like the GM s Acadia/Enclave/Outlook trio, feature unit body construction with a ladder frame underbody to improve side-impact protection, and independent suspension front and rear for a smooth ride. The vehicles also have true subframes front and rear for the powertrain and suspension. Ground clearance is 8 in. The brand-new 3.5L DOHC V6 is called the Duratec 35, with horsepower ratings currently up to 265. It fits in the same space as the Duratec 3.0, but that engine, which began life at 2.5 liters, was maxed out at 3. So in spite of tuning changes, it was underpowered at 221 hp when installed in a premium car. It continues in the Fusion/Milan as the optional engine over the 2.3L Four. The 3.5 V6 has variable intake valve timing only, although it s set up for the addition of variable exhaust timing, direct fuel injection and even hybrid drive. Ford calls it a Six Sigma engine, which means the design is so well verified that unless there s a problem at the manufacturing plants, it should be trouble-free. The engine does not have hydraulic lifters. The bucket lifters are select-fit, and there s a recommended valve clearance check with a feeler gauge (bucket on cam lobe base circle). If a bucket is worn out of spec, you have to select-fit a replacement using the number on it as a starting point. Example: the number refers to millimeters (3.31mm =.13 in.) and the replacement has a higher or lower number, as needed, to bring the clearance within spec. You may be able to do some switching around and reduce the number of new buckets required. The engine oil filter is on the rear side of the transverse engine, and there s a panel in the underbody cover that has to come off for access. The oil fill is qts. and a full-synthetic 5W-20 is specified. The new six-speed automatic transaxle, which has a very wide ratio range (6.04), is the product of a joint venture with General Motors, so you ll find a similar model on GM vehicles. November

9 The Ford transaxle has all-electronic shift control integrated into the PCM. The specific engagement, clutch fluid fill and drain characteristics of the solenoid pack are determined by transmission hot-testing, which is programmed into the PCM and entered into a database for the VIN. If the pack fails, the barcode on the transmission label will permit obtaining a replacement with the same characteristics. Backup data will eventually be placed on the Ford tech information website ( craftservice.com). As a result, it will not be possible to replace an individual solenoid, only the six-pack. If you see a Lincoln MKS with a 4.4 V8, don t be confused by another MK+ name. It s just the old Lincoln LS with a freshening up and a new name. The Shelby GT500 is a lot more than a Mustang GT with a Cobra emblem. Ford made many changes to turn it into a performance car and, as you d expect, they impact service. The supercharged version of the 5.4L V8, which produces 500 hp and 480 ft.-lbs. of torque, is a cast-iron block engine, with four-valve heads with variable intake and exhaust valve timing, similar to the limited production Ford GT. To help it breathe, there s a huge air cleaner (the mass airflow sensor is in the same housing), without the vapor trap used in the Mustang GT. However, the engine does have an electrically heated PCV valve to help with emissions. To feed fuel to the cylinders, high-flow-rate injectors are used. A full-synthetic 5W-50 oil is specified nothing else allowed and the pan takes qts. To deal with all the heat, the frontend cooling module has a specific highperformance radiator and condenser, an air-to-water intercooler, plus a power steering cooler loop. There s also a stacked-plate type engine oil cooler mounted on the engine. You may notice a small black box on the right side shock tower. Lift off the cover and you ll see a couple of relays and fuses that you won t find on the Mustang GT. One fuse and relay are for the fuel pump; the other is for the intercooler pump. The suspension resembles the one on the standard Mustang, although the tuning is very different. There s a much stiffer front sway bar to prevent understeer from the heavier nose (due primarily to extra engine weight). And there are two handling braces the familiar one across the shock towers, plus a second one that connects the rear lower control arm bushings. The power steering pump and internal valving for the steering gear also are different from the Mustang GT, and the differences in engine compartment layout affect steering gear replacement. The left side of the engine must be raised for clearance to remove the power steering pressure line clamp bolt and a steering gear mounting bolt. Ford offers special tools for the engine lift. Front brakes are 14-in. discs with four-piston Brembo calipers. The rears are single-piston calipers with vented discs. The transmission is the six-speed manual Tremec, but internally it s a much-beefed-up version of the one in the Mustang GT. There s still the solid rear axle, although it s a much stronger component than in the Mustang GT. The two-piece propshaft also is specific to the Shelby, with a clip connection between the sections. To help keep the insurance rates down, the Shelby Mustang has a multifaceted antitheft system. And if you operate a tow truck, you ll also want to be aware of the antitow sensor that s part of it. You might have to tow the car for even a flat tire, as the car doesn t come with a spare just one of those inflator kits that often doesn t work. Visit to download a free copy of this article. Circle #25 44 November 2006