Nov 222012
 

Powertrain – GT-R has a 3.8L V-6 with 545hp. Leaf gets 106mpg. Green and powerful = Nissan

Under the hood is Nissan’s 2.5L inline-4 (QR25DE) 16-valve DOHC engine with continuous variable valve timing control (CVTC). It generates 170 horsepower @ 5,600 rpm, 175 lb-ft of torque @ 3,900 (175 hp & 180 lb-ft non-PZEV) mated to continuously variable transmission (CVT) with 6-speed manual mode driving the front wheels. The CVT equipped here is Nissan’s 2nd generation Xtronic system. It received updates on the software to enhance engine braking, further eliminate the “rubberband” feel, and improves overall responsiveness. The gear ratio spans from 2.349 to 0.394 with a 5.798 final drive.

QR25DE

A lot of eyes were on the QR25DE, not only the QR was introduced with the all-new L31 Nissan Altima and equipped in the reintroduced Sentra SE-R in 2002 but it also replaced both the SR20DE and the KA24DE engines.

Both SR and KA are legendary Nissan engines of the same era that had two distinct characters. The SR was all-aluminum, light weight, high revving and mod-friendly. The KA was the robust, torquey workhorse with cast iron block that response to boost just as well as the SR out from the factory. On enthusiasts’ point of view, we are well qualified to say that SR and KA are two very unique engines of the same family since we are very fortunate to have proficient experiences. They sound, behave, and drive much differently from one another. Each have a loyal fan base as well, kinda like, the STI and EVO fans, except the SR and KA fans talk to each other with friendliness.

On the QR25DE, the aluminum cylinder head received the most engineering attention and it contains features than SR and KA could only dream off in their infancy. Nissan’s continuous variable valve timing control (CVTC) is employed on the intake cam. As the intake cam timing can be retarded or advanced, valve overlap is dialed in to allow exhaust gas recirculation to eliminate the EGR valve that simplifies emission control equipments. Both friction and component mass in the valvetrain are also reduced from the use of direct-acting cam-on-bucket design, and micropolished narrow cam lobes.

Mated to the cross flow cylinder head is the thin-wall aluminum casting intake manifold that features electronically controlled dual path intake runners. The short path is used at above 5,000rpm under load to enhance volume efficiency. The long path is used for lower-rpm to enhance torque. On the exhaust side, the close-coupled catalytic converter is integrated with the tubular, stainless-steel 4-into-1 header exhaust manifold and mounted up-close to the engine for it to reach operating temperature as quickly as possible.

Below the cylinder head is the light weight thin-wall die-cast aluminum open deck block. The block provides home for 89mm bore and 100mm stroke that spells torque in this undersquare layout. The connecting rod is 163mm long with a 1.63:1 rod/stroke ratio mated to the forged and micropolished crank journals.

To reduce secondary vibration inherit to a large displacement 4-cylinder engine, balance shafts are utilized. The balancing assembly is mounted in the upper oil pan near the oil pump and consists of twin counter rotating shafts that spin at twice the speed of the crankshaft.

With all that being said, the early production QR25 had some durability issues due to the premature failure of the manifold mounted catalytic converter and butterfly screw in the dual path intake manifold that would loosen itself. Although the failure rate wasn’t as widespread as the Toyota engine oil sludge problem, the QR25DE received upgrades in 2007 to address these issues and to further improve the engine.

The upgrades replaced the original dual path aluminum intake manifold by a large diameter single path composite manifold with incorporated swirl control valve in PZEV engines. Raised engine redline and increase power output by change of compression ratio to 9.6:1 (from 9.5), revised camshaft profile, stronger con-rods and further use of molybdenum coatings on the piston skirts to reduce friction.

Despite its age, the QR25DE is retained in the all-new 2013 Altima (L33) and capable of delivering 38 mpg on the freeway.

Did the QR retain both distinct characters and fan base? I am afraid there isn’t a fine line to say yes or no. Yes, the QR did retained KA’s strong low to mid range torque character along with some diminished NVH at high rpm. Yet, the SR attributes were gone.

On the road, throttle tip-in from the drive-by-wire throttle is a bit aggressive. The car will lurch forward at the first inch of pedal travel. After that the pedal has linear input. Consider the low odometer reading on the tester (less than 2,000 miles), the tip-in aggressiveness should be tamed as miles accumulate. Place the CVT in manual mode, it’s shifting is as responsive as Euro’s finest DSG/DCT transmissions. It up-and-down shifts quickly and smoothly.

Pin the throttle to the floor taking the engine to its 6,200 rpm redline, the powertrain is capable of propelling its, respectable, 3,192 lbs curb weight from complete stop to 60 mph in ~8.5 seconds, and reaches quarter mile in ~16.5s @ 87 mph. These acceleration figures are right at the norm of the class segment.

Cruising at 70mph, engine speed stays at fairly low 1,800 rpm for a 4-banger to conserve fuel. Thanks to the healthy low end torque, the Altima doesn’t feel like it is in the wrong gear lugging the engine. Combine with CVT’s quick response to throttle input, the engine revs up to desire rpm very quickly for instantaneous acceleration when needed.

Our 850 miles test route, took us to Monterey Park from the Bay Area, the observed fuel consumption ranged from 26.4 to 28.1 mpg which were within EPA’s 23 City, 32 highway and 27 mpg combined rating. The fuel tank has 20 gallon capacity that could yield over 500 miles distant-to-empty range which would be sufficient to go from the Bay Area to San Diego in one tank of fuel – making the Altima the ultimate road trip choice.

Brake – Confidence inspiring.

Four wheel discs brakes are spotted on the car. Front consists of 11.7” x 1.02” vented, and 11.5” x 0.35” in the rear. In the name of safety, All Altimas came standard with 4-channel Anti-lock Braking System (ABS) with Electronic Brake force Distribution (EBD) and Brake Assist along with Vehicle Dynamic Control (VDC) with Traction Control System (TCS).

To comply with current federal regulation on brake pedal operating effort, the Altima is not the lone player in the market with a low effort pedal. It is not what car enthusiasts’ would prefer but otherwise, the pedal feels right-at-home, Nissan. It has linearity in response – the harder you step on it, the harder it stops – which makes for intuitive modulation.

The brakes are sufficient to endure the 4,000 ft descent from Red Box Saddle at Angeles Crest Highway back to sea level. No fade was experienced. It is capable of stopping the car from 60 mph in 124 ft.

Interior – If you have been inside an Infiniti, you will understand the elegance.

Situate in the cockpit, the first thing noticed is the elegant Fine Vision Illumination gauge cluster. The cluster has three rings to define the speedometer, tachometer and one for coolant temperature and fuel level gauges. The rings are protruding out to present a 3D effect. The gauges have white background, red dials with an orange LED multi-function screen that displays vehicle information such as instant MPG, maintenance notices…etc. With the ignition off, the entire gauge cluster is shaded black.

The previous generations of Altima, and even the L32, consumers criticized the interior workmanship when it was first introduced to the market. With the facelift in 2010, Nissan took the initiative to rework the interior to make it on par with the segment. The dash material is soft to the touch, good to look at, and panel gaps are minimal.

The switchgears are logically layout making them very intuitive to use and operate with quality feel and in appeal. The Intelligent Key system makes you feel like you are driving a Nissan just when you are unlocking the door to enter the car. Nissan is seemingly one of the very few manufacturers to widely use this technology even at the bread-and-butter level models. Once you tried, you will understand how convenient this could be. Not needing key to open door or trunk, or to start the car is priceless.

Being a family sedan, the passenger compartment has a lot of storage bins to accommodate the commodities needed for the journey. The door panel pocket is can fit two standard size bottle water in addition to three cup holders at the center console behind the shifter. Arm rest compartment has two-tier design; top is great for cell phone and wallet. Bottom tier is very deep and include a charge port. In front of the shifter is a flip up compartment has room for a roll of triple-ply toilet paper, and also contains a charge port. Glove compartment is huge as well. Trunk is 15.3 cu-ft big.

For occupants, there are plenty of leg room front and back. Front seats have great thigh support to make long journey comfortable. Lateral support is sufficient to hold you into the seat during spiriting driving. Driving position is also easy to find aided by the height adjustable driver seat and tilt-and-telescope steering wheel.

The standard sound system has 6-speaker with auxiliary input. Output is lack of bass and average in sound quality. For those enjoy lively music while driving, the optional Premium Audio Package with 9-speaker Bose system will light up your day. Headlight visibility is great for being halogen reflector style housing. The light can get pretty far distant and with even beam spread – field tested pitch-dark in the dense fog on I-5. Speaking of safety, the Altima came standard with eight air bags. It also earned the highest frontal offset, and side impact IIHS, Insurance Institute for Highway Safety, ratings.

Overall Impression

Scoring System:
Powertrain Performance & Refinement
8

Handling & Ride Characteristics
8

Brake Performance & Feel
8

Comfort & Workmanship
8

Features & Technologies
8

Will I buy one factor
8

My recommendation factor
8

Lamzgarage factual ratings. Dollar-to-Horsepower: $138.2/HP; Dollar-to-Trunk Space: $1,535.3/cu-ft.

Afterthought – We’re not bias

Here in Lamzgarage, we’ve recently driven the Chevrolet Malibu, Mazda 6, Mitsubishi Galant, Subaru Legacy, we can say that the Altima would be one of the best choices. If you are in the market for a mid-size sedan, the brand new 2013 Altima is available as of this writing. Also, with the very good looking Kia Optima, and the equally capable Hyundai Sonata twin that both offer standard 200 hp direct injection engines. Be sure to test them out before being sidetracked by the number of Toyota Camry and Honda Accord clogging the road. Perhaps, wait for just a little longer to check out the upcoming 2013 Mazda 6. Rumors are it might come with an ultra eco-friendly diesel engine.

To show the unbiased nature, if we are the shopper looking for a mid-size sedan, we will add an extra $1,000 for a 2013 Ford Focus ST. End.

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