After providing you with an exclusive first-drive of the all-new 2009 Acura TL and TL SH-AWD recently, Leftlane writer Gary Anderson has decided to go back and take a more extensive look at each model individually starting with the performance-oriented TL SH-AWD today and the standard TL next week.

In past years, Acura has attempted to capture enthusiasts who had cut their teeth on other Honda products by offering a Type S version of the TL, with more power and a tighter suspension in the same front-wheel drive chassis. With the all-new 2009 TL, Acura has dropped the Type S; the high-performance version of the TL now comes in the form of the SH-AWD model. This “Super Handling” version uses a high-tech all-wheel drive package to make a run around end, leaving the front-drive and rear-drive enthusiasts still butting heads in the middle of the field. In our view, this is a goal-scoring technology maneuver that may change the rules of the handling game.

We had the opportunity recently to test this strategic new Acura product on California’s gorgeous twisting coastal roads north of San Francisco, and then refresh our memory of the 2008 TL Type S in a quick loop drive near Sausalito. Our conclusions were two-fold: First, on every measure, the SH-AWD clearly outperforms the Type S that it replaces, but it delivers a different sort of driving experience. Second, the improvements in style and luxury shared with the standard TL have created a performance sedan that seems more likely to appeal to grown-up enthusiasts, rather than one to which young drivers will aspire.

What is it?
The Acura TL SH-AWD is an unabashed sports sedan, with a 3.7 liter all-wheel-drive VTEC engine producing 305 horsepower and 273 pound-feet of torque. Incidentally, that’s the most powerful engine Acura has ever built.

Power gets to the wheels through a paddle-controlled five-speed automatic transmission and an electronically controlled all-wheel-drive system that can vary torque not only front to back but between the rear wheels to provide optimum power to each wheel in any type of driving maneuver.
The SH-AWD also incorporates duct-cooled front brakes and a high-performance exhaust system which also provide the only design clues that it is different from the standard TL since in all other respects, the two models are identical.

What’s it up against?
Acura is going after the luxury sport sedan customer with the SH-AWD, compelling the engineers to benchmark it against the BMW 5-Series, Cadillac CTS, Mercedes E-class, Audi A6, Lexus GS 350, and Infiniti M35. That’s a tough crowd to match in a sedan that’s expected to sell for under $42,000.

Nevertheless, the product planners believe they’ve achieved their goal. Their qualitative evaluation scales of luxury and performance/emotional appeal show the new TL positioned beyond everything in the performance/luxury sedan category except the Audi A8 and BMW 7-Series. It’s worth noting that the TL SH-AWD is positioned to compete with larger cars than its identically-sized, less-powerful sibling, the standard TL.

Any breakthroughs?
Phew! There are so many innovations incorporated into the new SH-AWD that we can best discuss them under the subheads of drivetrain, suspension and engine.

Drivetrain
We’ll start with that “super-handling” all-wheel drive system, since that’s important enough that Acura names the car with it. The Acura engineers made two statements that summarize what they consider to be important. First, they say that the system is intended primarily to improve handling, rather than just enhance safety in wet or slippery conditions. Second, they make the claim that this system actually provides better handling than any car with traditional front-wheel drive or rear-wheel drive. Did you hear that, BMW?

So how does it perform this miracle? Standard all-wheel drive systems, intended primarily to improve handling safety, have some form of clutch between the front and rear wheels. This clutch allows power to be directed to the end of the car that has the most grip, overcoming any loss of grip due to weight shifts caused by acceleration or braking as well as differing road surfaces. If power needs to be reduced to stop a specific wheel from spinning, that is done by using the ABS system to brake that wheel. Though this does keep the car from rotating, it does it at the expense of loss of power.

The Acura system starts with a electronically-controlled multi-plate clutch between the front and rear wheels. Under normal cruising conditions, the system directs 90 percent of the power to the front wheels to maximize fuel efficiency by reducing drive-line power loss. Under acceleration and hard cornering, as much as 70 percent of the engine’s power is directed to improve handling and negate torque-steer. Given the range of power shifts, that capability gives the SH-AWD pretty much the best of both the front-wheel and rear-wheel drive world.

However, in addition to this capability, the Acura system has separate electronically-controlled multi-plate clutches between the rear differential and each of the rear wheels, which allows as much as 100 percent of the rear-wheel power to be directed to either wheel. Consequently, not only can power be proportioned between the front and rear of the vehicle, but it can also be proportioned between the rear wheels without the loss of power that would result from using wheel braking to minimize wheel slip.

This attribute is useful, of course, in situations where one wheel loses its grip and starts to spin, but its key advantage is that the outside rear wheel can actually be “overdriven” in tight curves. The result is that the wheel which is traveling the longest distance in the curve is actually turning faster than the other wheels, overcoming any tendency towards understeer. More about this when we discuss our experience with the SH-AWD.

Suspension
Of course, any system that controls power to the wheels is going to work best if it doesn’t have to overcome significant amounts of body pitch and roll. The TL engineers have generally done a good job of balancing the springs, shock absorbers, and anti-sway bars to minimize weight shifts without sacrificing ride quality.

In recent years, to improve ride quality under all driving conditions, Acura has introduced a two-valve shock-absorber design. During normal cruising, both valves remained open, so that bumps encountered when driving in a straight line could be absorbed with a minimum of passenger discomfort. However, when cornering, one of the valves would shut so that shock movement was restricted to keep the vehicle level. Pretty nice: a soft ride on the straights, and a taut ride on the corners.

In the 2009 TLs, Acura has gone one better in the shock department, by introducing a new generation of dampers that have blow-off dual stage valves, which retain the two-level shock absorption capability but improve the response time, so that in a situation where a pothole is encountered on a tight curve, the bump will be cushioned without unsettling the car or passengers.

The result here is that the TL is getting most of the variable damper response now being built into high-end luxury cars through the use of sophisticated electronically-controlled shock absorbers, but at considerably less cost since the mechanical system is simpler to manufacture.

To take advantage of these handling improvements, in the SH-AWD, engineers built in more responsive variable electronic power steering assistance. This system increases assistance at low speeds to make parking lot maneuvers easier and reduces assistance at speed to maintain directional stability and improve feedback and turn-in response.

Engine
As noted in the statistics, the SH-AWD also is equipped with a higher-capacity and consequently more powerful version of the TL’s VTEC engine. This engine produces 305 horsepower and 273 pound-feet of torque, an increase of 25 horsepower and 19 pound-feet of torque over the standard TL, achieved by increasing engine capacity from 3.5 liters to 3.7 liters.

But what’s interesting is the way engine volume is increased. While the smaller engine in the TL uses iron cylinder liners in an aluminum block, the larger engine uses thinner high-silicon aluminum liners. These aluminum cylinder liners have the same distances between cylinder bore centers but dissipate heat more efficiently between adjacent cylinder bores.

With the additional power, Acura has tweaked the SH-AWD engine in a couple of other ways. The throttle body is proportionately bigger to provide better fuel-air flow into the engine, coupled to reprogramming of the “throttle-by-wire” system. Coming out of the engine, the exhaust is directed through exhaust manifolds cast directly into the cylinder heads, and into a high-flow sport-tuned dual exhaust system with quad exhaust tips at the rear.

Of course, any increase in engine power can come at the expense of gas mileage, but the engineers have come up with an answer to this problem as well for the more powerful SH-AWD.

As everyone who knows about Hondas is aware, VTEC means “variable valve timing and lift electronic control” (Shouldn’t that be the wordy VVTALEC?) which in previous Honda and Acura engines has meant that the timing and lift on the intake valves could be altered electronically by changing the positions of the intake lobes on the camshaft. The consequence was a precise metering of the air-fuel mixture relative to the cylinder position across the range.

Now the Acura engineers have re-engineered the camshaft on the SH-AWD engine so that the exhaust valve timing can be altered as well. The result is a near-optimal intake and exhaust cycle at all RPM, which means improved fuel efficiency as well as engine performance. Bottom line? City mpg of 17 and highway mpg of 25, one mile per gallon less than the standard TL, while the engine still meets the more stringent California LEV II standards for ultra-low emission vehicles (ULEV).

Oh, and one more technological improvement: Underneath the skin, Acura has improved the skeleton of the chassis shared by both models to increase torsional rigidity while increasing crash zone responsiveness, which is earning them five-star ratings in front, side, and rear collision testing, a designation achieved by very few other automobiles on the market.

How does it look?
In the earlier TL review, we discussed the new exterior design, and we had to say we weren’t overwhelmed. While maintaining the overall lines of the previous TL – wouldn’t want to scare away repeat customers – the design of the new model has been changed slight by sharpening the feature lines into paper-fold edges. This would be interesting if Cadillac hadn’t done the same thing a few years ago. Beyond that, Acura has changed the front grille to follow the changes it has incorporated on other cars in the Acura line-up. It is certainly distinctive, but even objective observers can’t help note the beaver-like effect it has on the front “face” of the car.

Our view carries over to the SH-AWD for the simple reason that the more powerful model is virtually identical to the standard TL. The only difference in front is that the SH-AWD incorporates cooling ducts that direct air from the lower front fascia to the front brakes, which means that the signal/parking lights had to be redesigned to share the opening in the fascia. In the rear, the rectangular dual exhaust tips of the standard TL are each divided into two for the quad-tip exhaust of the SH-AWD.

That similarity with the TL is a shame, since the SH-AWD is a high-performance car with a truly innovative approach to handling and power, and it deserves to be more distinctive. We expect that buyers who agree with our performance assessment are going to be firing up their computers to look for distinctive aftermarket touches as soon as they buy their car. Unless they do, the car they’re taking to the track to whomp up on the BMWs is going to look just like the car the nice older couple down the street bought last month.

And inside?
On the inside, the interior trim is quite pleasing, using high-quality materials of soft-touch vinyl and leather trim, accented with an attractive, pleasant-feeling metal composite material. We liked the choice of materials and the workmanship very much, and definitely felt that the composite metal trim was superior to both the brushed aluminum and retro polished wood that are the typical clichés of most luxury car lines.

The front cabin has been sculpted to create two visually separate passenger spaces, divided by an imposing center console.

Overall, we like the interior, except for the design of the center stack, which is excessively busy. Not only does it have a knob or button for every HVAC, audio, and nav function, it also has a doorknob-sized circular center control which provides redundant control of most functions.

Unfortunately, even inside the car, friends who are impressed with the handling and power of the SH-AWD, probably aren’t going to notice the few changes that distinguish the high-performance model. About the only differences are in the steering wheel, which is slightly fatter than that of the standard TL, and in the stitching on the steering wheel and shift knob wrap, which is more pronounced. We wouldn’t want to see the red gauge rims and fake alloy pedals of the old Type S, but maybe a few logos or extra gauges or something wouldn’t be amiss.

But does it go?
The two-lane coastal roads north of San Francisco were a perfect venue to put the SH-AWD through its paces. From Sausalito along Route 1 to Bodega Bay we could enjoy intricacies of the curves while once in awhile stopping to take in the breath-taking coastal scenery.

On this great driving route, the SH-AWD was perfect for the tight curves and unexpected camber changes. Whenever we got some space in traffic, we could enjoy the sensation of taking curves at invigorating speeds. The noteworthy feature of the SH-AWD was how competent it was when responding to an unexpected change in camber or curve radius.

With most high-performance cars, even the new M3, when conditions change unexpectedly, you’ve got to be prepared to drive the car; though other high-performance cars are capable of allowing the driver to handle issues that might arise, they don’t actually help with the task.

In contrast, the modulated torque to each wheel in the SH-AWD actually pitches in to help you handle anything you encounter. It was almost as if the car’s outside wheels developed claws, scrabbling to pull the car around the corners like some living thing.

The other advantage of the SH-AWD is under the hood and in the transmission. Route 1 is notorious for slow sight-seeing traffic and sparse passing zones, so when opportunities did present themselves to make a pass, it was a simple matter to flick the paddle to downshift the car and, with an automatic blip of the throttle, go from 40 to passing speed in a very short distance. At that point, the improved brakes were more than capable of slowing the car down to the typical 30-40 mph needed to take the next curve.

One surprising factor was in the transmission. When we were told in the briefing that this super-fantastic new beat-everything-on-the-road car only had a five-speed automatic transmission, we weren’t the only ones in the room who raised our eyebrows. But however the Acura engineers did it, with electronic throttle control and wider gear ratios as they claimed, or by black magic, this transmission works exceptionally well.

On the SH-AWD, gear changes in sport mode are as fast as we would ever be able to manage with a manual stick, complete with an automatic throttle blip to smooth out transitions. Couple that with the convenience of being able to downshift from the steering wheel to make a quick pass or slow the car on a long downgrade while the transmission lever remains in drive, and we had no complaints whatsoever with the transmission.

The smoothness of the ride was also gratifying. In recent drives in the Nissan 350Z and BMW M3, we realized our passengers were paying a price in ride comfort so that we could enjoy taut handling response. With the SH-AWD, there didn’t seem to be any trade-off. Under cruising conditions it was comfortable, but when the curves got tighter the car just sucked it up and handled whatever was thrown at it.

Why you would buy it:
The performance of the SH-AWD, particularly at a price that’s promised to be around $42,000 (the TL is manufactured in Marysville, Ohio, which means they benefit from exchange rate fluctuations that hit their European competitors) is reason enough, and the nice cabin features and smooth ride are a bonus that will impress the in-laws.

Why you wouldn’t:
It’s going to be hard to deal with the fact that this high-performance sedan looks just like the plain-vanilla version, even if the hard-edged design and distinctive grille are to your tastes. The busy interior design is also a bit low-rent for the money.

The SH-AWD will be on sale in November of this year. Look for exact pricing to be announced here in the coming weeks.

Words and Photos by Gary and Genie Anderson

2009 Acura TL SH-AWD