From the March 2006 Issue of Car and Driver.
Cadillac’s V-series is to that nameplate what AMG is to Mercedes or M is to BMW. It’s the high-performance wing of the company, where the original product (and its price) gets kicked up some serious notches. It is also a pretty brave enterprise at Cadillac. Running up your colors in the company of cars that define the art of corporate hot rodding is an unmistakable signal of intent.
With its XLR-V, Cadillac puts a player in among the SL55 AMGs and Jaguar XKRs of the world—cars with performance and pedigree to spare. So how does the XLR-V match up, this low-slung, high-end pretender to the thrones of Europe?
In some areas, very well indeed. The new supercharged 4.4-liter version of General Motors’s Northstar V-8 is an exceedingly sophisticated engine. Pressurized by a GM-designed and patented Roots-type blower made by Eaton, the engine supplies prodigious torque throughout most of its operating range. Continuously variable valve timing at all four cams undoubtedly helps spread the available torque around so the car almost always responds to a jab of the pedal with a surge of acceleration.
The Northstar is also endowed with desirable versatility, able to purr around at lower engine speeds as befits a luxury marque, then snarl to the redline with almost shocking ferocity. Part of this Jekyll-and-Hyde act is due to a muffler that suppresses low-rev noise levels and then switches to a more free-flowing mode at higher speeds when a vacuum-operated valve opens, allowing the exhaust gases a more direct path to the atmosphere.
Also part of this suave schizophrenia is a host of detail work done on the Northstar to retain necessary levels of refinement along with elevated power output. The reduction in displacement (from 4.6 to 4.4 liters) was achieved by reducing the size of the cylinder bore—thus increasing the amount of metal between those cylinders—and was considered necessary in the interests of durability. That blower is housed in a casting that is integrated with the Laminova tube-type intercooler and the intake tract in one rigid unit, and it works extremely well at reducing unwanted supercharger whine.
The engine block is a unique casting that provides improved coolant flow and has a new oil gallery to supply under-piston cooling jets. Lower-compression cast-alloy pistons necessitated a rebalancing of the crankshaft, and the accessory drive required a redesign and a new, wider three-sheave pulley to power the blower. That’s no small issue, since the supercharger soaks up nearly 80 horsepower at maximum speed.
Still, the engine manages to keep some of that extra power to itself, punching out 443 horsepower at 6400 rpm, which is enough to propel this 3840-pound convertible to 60 mph in 4.7 seconds and through the quarter-mile in 13 seconds flat. More important to everyday users is the 414 pound-feet of torque, of which 90 percent is available between 2200 and 6000 rpm.
All that torque just about precludes the need for a downshift in most scenarios, but the intelligent 6L80 six-speed automatic transmission will probably hand you one (or two) anyway when you squeeze the throttle. This rear-mounted six-speed provides almost intuitive response to a driver’s inputs with Caddy’s performance shift algorithm, which refrains from shifting up on a trailing throttle when cornering. It can be operated in manumatic mode by tapping the lever into an adjacent selector slot. This action also informs the magnetorheological shocks to switch to sportier settings.
The XLR-V‘s chassis is upgraded from the naturally aspirated base model’s by having a solid front anti-roll bar, a rear anti-roll bar (not present on the V-less XLR), stiffer rear lower-control-arm bushings, and a recalibrated ride program. All of this results in a flat and well-controlled stance on the road, and the ride is still considerably better than that of the Corvette with which this car shares so much platform architecture. At least part of that arises from the more-modest tire sizes, increased though they are from those of the base XLR.
In supercharged form, the XLR-V wears 19-inch wheels and rubber, but with nothing like the width found on its Corvette cousins. The rear tires are 255/40R-19 Pirelli run-flats. (The Vette runs 285s on “normal” models and 325s on the Z06.) The result is a car that can be used as an everyday commuter with far less drama and inconvenience than can its bow-tie-badged brothers.
Smaller tires affect the car in other ways, of course. On the skidpad, we could only wring 0.87 g of grip out of the XLR-V, which was far below GM’s claim of 0.94 g. Also, the braking distance was a longish 176 feet, despite the V-series brake upgrade—basically a set of Z51-spec rotors and calipers also lifted from the Corvette parts bin. These small compromises in overall performance are worth tolerating for the comfort and luxury you get in exchange.
Noise levels are low enough—some road roar aside—to allow full enjoyment of the nine-speaker Bose stereo with the hardtop in place. This Caddy has a navigation system, dual-zone climate controls, fully powered seats, keyless door opening and engine operation, and the tactile delights of French-stitched leather coverings throughout the interior. These improve the ambiance considerably. The XLR always suffered somewhat from the modern angularity of its design. The V-series’s textural additions soften the overall effect.
In trying to strike the important balance between high-performance integrity and luxurious isolation, the XLR-V occasionally falls between two stools. On some road surfaces we noted a little body-structure quiver like that of the stiffly sprung Corvette, yet on the ubiquitous grooved concrete freeways of Los Angeles, the car proved surprisingly smooth and tranquil.
Cadillac employs GM’s magnetic steering mechanism to vary effort, and although the XLR-V‘s wheel feels a little leaden at low speeds, it improves to a reasonable heft in the driver’s hands as speed rises. But the wheel never transmits the stimulating feedback you get in the best sports cars. To be fair, though, the XLR-V‘s likely competitors in this market–the BMW 650i, the Mercedes SL55 AMG, the Lexus SC430–have similarly inert steering mechanisms.
We can’t complain about steering accuracy. The XLR-V goes pretty much where it’s pointed, and the chassis geometries reveal no serious handling vices. Not that it could go astray with the StabiliTrak control standing by to intercede in the event of horseplay. You can disable the traction-control portion and switch the stability to a less intrusive strategy, but you can never make StabiliTrak go away completely.
This is not a serious problem for most drivers (we leave the system on in normal driving situations, too), and it’s a positive benefit for the average owner. Another safety technology—this one exclusive to the V-series—is a system that swivels the headlights in corners to improve the illuminated field of vision. Try this before you deride it as technology for its own sake; trust us, it’s advantageous to see where you’re going.
Having the versatility of a fully automatic retractable hardtop is advantageous, too, even if the device eats up luggage space. Still, as we’ve said before, you would be wise to drive to your weekend destination with the top up and stash your luggage inside the resort before motoring around the lake with the top down. An equal handicap is the absence of storage space behind the seats. There’s an upright storage bin between the seatbacks, but it will only accept something about the size of a large tissue box.
As high-performance roadsters go, the XLR-V is quite well-suited to the quotidian requirements of your less-extreme motorist. There’s no super-low chin spoiler to mash on parking curbs. There are no limbo antics necessary to get in and out. The car has all the creature comforts technology can provide, and its unique mesh grille, supercharged badge, and four shiny tailpipes tell everyone this Cadillac is a cut above.
For those who think 100 grand is a reasonable amount of money to spend on a car, this Cadillac is certainly worth a look.
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