Slice and Dice - 2008 Lotus Exige S 240, 2008 BMW Z4 M Coupe, 2008 Porsche Cayman S

Like everything else in the modern automotive realm, the term `sports car' seems to have a pretty subjective definition. Ask 10 different people what a real sports car is and you'd probably get 10 different interpretations.

Still, it's hard to argue that the three cars featured here are anything but. Each shares a common trait or two: rear-wheel drive, sharp handling, a favorable power-to-weight ratio and a fixed-roof cockpit equipped with two seats.

Every now and then, we manage to slip the manacles to the daily production grind and hit the road for a bit of actual driving. And these three cars presented an ideal opportunity. The trip covered two days, more than 800 miles, 6,500 vertical feet, and every road and weather condition imaginable--from long, blustery desert blasts to towering switchbacks with zero emergency runoff, to gleaming, snow-dusted mountain passes. It revealed three vehicles that have their own distinct personalities, even though they've all been assembled for a similar purpose.

Proving that these cars even possess a modicum of functionality, we packed our tents, sleeping bags and a change of clothes with the photo gear and actually went camping at the end of the first day (really). And to avoid angering the various enthusiast camps with their pet definitions of a sports car, we won't call them that any more. We'll just call them canyon carvers.

Lotus Exige S 240

The ascetic choice

A lot of hype surrounds this car from engineering and so-called `purist' circles--that is, people who appreciate the bare basics in an automobile and nothing else. Lotus has traditionally eschewed creature comforts like air conditioning, power assist and cushioned seats in the pursuit of a completely raw and undiluted driving experience. The Exige S 240 is the latest embodiment of that philosophy.

The cockpit is cramped and noisy, and it's difficult to steer at low speeds due to the absence of power steering. But turn into your first corner at speed, crest your first apex and it quickly becomes clear there's nothing else like it on the road today.

The S iteration supercharges the Toyota-built 1.8-liter four-cylinder engine and adds close to 30 hp to the previous Exige's 190-hp peak. The S 240 features a more efficient intercooler fed by a larger integrated roof scoop and pushes power by another 20 hp (hence the 240 designation). Off the line, the S 240 still doesn't feel particularly fast, but it isn't really about straight-line speed. It's more about building revs to keep the supercharger on the boil, screaming into bends and maintaining silly velocities through the exit thanks to unbelievably flat cornering. And the faster it goes the more stable it becomes, the aerodynamics sucking it ever closer to the pavement and generating a reported 100 pounds of downforce at 100 mph.

On a tight, twisting road, there's no doubt the Lotus carves the hardest of the three and maintains cornering speeds with the greatest confidence. In this respect, it's a perfect weekender or track-day toy, albeit a pricey one ($60,000 and change to start). This particular Lotus isn't as spartan as some, equipped as it is with the Touring Pack, which adds leather seat and door trim, an Alpine stereo with iPod connector, additional sound insulation and full carpeting (basically a set of floor mats).

Even so, living with it on a daily basis would take a special sort of individual. Two grown men can fit inside, but they may occasionally find themselves dueling elbows. Or the driver may inadvertently grab the passenger's knee while reaching for the shifter. Rearward visibility is severely compromised by the intercooler, which is vertically mounted directly behind the cabin. The car comes with an interior rear-view mirror, but about the only thing it's good for is pointing it out the passenger window to help monitor the blind spot.

Ingress and egress aren't easily accomplished. Getting in requires negotiating high and wide door sills and the non-adjustable steering wheel. Getting out can only be described as clambering. The car has more storage than might be expected. The entire rear end behind the central engine bay is hollow, although everything must fit through an opening about the same diameter as a human torso.
To deride the car for its inherent asceticism, though, is to miss the point. Any complaints are quickly forgotten once the curves are reached.

2008 Lotus Exige S 240
Layout
Transverse mid-engine, rear-wheel driveTransmission
Six-speed manual
Performance
Peak Power: 240 hp @ 8000 rpm
Peak Torque: 170 lb-ft @ 5500 rpm
0-60 mph: 4.0 sec.
Top Speed: 150 mph (est.)
Base MSRP: $64,890
Price as Tested: $70,060

BMW Z4 M Coupe

The wild animal

Anyone who's spoken to me in the last year or so knows how much I like this car--but I'll concede that it has its flaws. Its biggest problem making friends seems to be an inherently feral nature.

Not that it imparts the same raw, no-compromise driving experience of the Lotus. It's just difficult to deal with, being that you really have to muscle the car around to get any response from it.

It's especially true with the steering and gearshift. Some have complained that the shifter is notchy and imprecise. I don't consider the feel notchy, just very positive. When the lever is slammed home, you know without a doubt you're in gear. In the Lotus, for example, the throws are so short and closely grouped that I often second-guess the gear selection. And I don't consider the M's shifter imprecise. I quite enjoy the extremely stiff, deliberate feel; I've put about 15,000 of the car's 19,000 miles on it and have never missed a shift (honest).

Another important complaint is that the car is `squirrely' and `edgy' (that last comment from BMW brass, no less). Edgy, yes--though BMW claims 50/50 weight distribution, the M is one of only a handful of modern cars with a distinct propensity toward oversteer at the limit. Engineering editor Febbo attributes this to its forward-mounted engine (see sidebar).

This is the only one of the three with a standard-fit limited-slip differential. With that diff and a torque-rich, 330-horse inline six, the M offers the most aggressive and intoxicating acceleration. On long, sweeping sections of road, it seems to walk away from the other two. It also feels the most stable at high speeds, thanks to generous amounts of tire and a 98.3-inch wheelbase.
Considering this is the most massive car in the group, braking power is suitably muscular. The large, cross-drilled rotors offer a good amount of bite under hard use, and pedal feel is extremely firm with just a tiny bit of play for ease of modulation.
Its biggest drawback is overall visibility. The rearward and lateral rear views are fairly terrible (although not non-existent, as with the Exige S 240). Forward visibility is the worst in the group as the driver tries to peer past that long nose, making apex navigation a chancy proposition at times.
The best thing is the seating position. The cockpit really wraps around you in a way the others don't. I can adjust the seat and steering wheel so that both elbows are supported on comfortable pads on the center console and door insert with hands placed at three and nine, allowing steering input with minimal effort.
More difficult to control than the other two, the Z4 M Coupe still makes for a potent carving machine. It just needs a little more work and a little more brass to make things happen.
 

2008 BMW Z4 M Coupe
Layout
Longitudinal front engine, rear-wheel drive
Engine
3.2-liter inline six, dohc, 24-valve
Transmission
Six-speed manual
Performance
Peak Power: 330 hp @ 7900 rpm
Peak Torque: 262 lb-ft @4900 rpm
0-60 mph: 4.9 sec.
Top Speed: 155 mph (limited)
Base MSRP: $50,100
Price as Tested: $57,500

Porsche Cayman S
The baby GT
The Cayman is an interesting study compared with the Exige. While older Porsches (like the first 911s) were also lightweight, raw and minimalist, the modern Cayman is something else entirely. That's not to say it isn't a capable canyon carver, because it is. But of the three, it feels the most insular, the most luxurious and the least hardwired to the road.

Ride quality is good over all surfaces, more so than either the Exige or the M, both of which can beat the hell out of you on bad pavement. Because of this, you might expect it to be slower through the corners, but--thanks to Porsche's sophisticated PASM stability management--even the tightest hairpins can be tackled with sporting precision. Its mid-engine configuration allows it a slight rear weight bias, but it remains neutral, even at high speeds. Steering input and feedback are good, but control feels somewhat compromised by the wheel. Compared to the M's meaty, sculpted tiller or the Lotus' small-diameter, perforated leather-skinned number, it looks like it could have come out of a Peterbilt. Still, once you really start pushing, the car slices through corners with great alacrity, its ability to carve seemingly limited only by the willingness to trust.

Acceleration is more languid and less dramatic than in the other two cars, adequate but not real snappy--in spite of decent torque. The brakes are possibly the most disappointing aspect, with fairly long, mushy pedal travel and feel, and not a whole lot of bite at the end of the stroke. The shifter, however, is likely the most accurate and easily used, so precise and feathery light, shifts are executed with a flick of the wrist.

Overall, given the compliant ride quality, comfortable seats and a good amount of storage space (items may be stowed either under the rear hatch or under the front hood) the Porsche could make the best all-around road-tripper. Seen this way, the Cayman S offers the best of two worlds: an ability to carve when the need arises and a propensity for long-distance touring.

Possibly the most curious thing about the Cayman S (and the most aggravating to Porsche-philes), is its positioning within the company's model line. It's billed as the entry-level model, the ramp up to the 911, but by all accounts the mid-engine layout makes for superior handling characteristics. The only thing holding the Cayman S back seems to be engine displacement: 3.4 liters pushing 295 hp against the base Carrera's 3.6 pushing 325. Many believe that a comparably powered Cayman would spank its bigger brother up and down any given canyon road. Could the Cayman represent the precursor to the 911's eventual mid-engined successor?

 

 2008 Porsche Cayman S
Layout
Longitudinal mid-engine, rear-wheel drive
Engine
3.4-liter flat six, dohc, 24-valve
Transmission
Six-speed manual
Performance
Peak Power: 295 hp @ 6250 rpm
Peak Torque: 251 lb-ft @ 4400 rpm
0-60 mph: 5.1 sec.
Top Speed: 171 mph
Base MSRP: $59,100
Price as Tested: $65,780

The mass factor
This is what really separates the cars. It isn't just the weight but where it's located. The BMW and the Porsche are similar in heft at 3,230 and 2,976 pounds respectively. The Lotus is a scant 2,077 pounds, but that isn't the whole story.

BMW claims the Z4 M to have 50/50 weight distribution. However, it feels like the car rotates around the engine, which is, of course, forward-mounted. The Porsche has a slight rear bias at 45/55, but feels extremely neutral. There's no real sense that the car wants to pirouette around its center of gravity like most mid-engine cars. The Lotus has a decidedly rearward weight bias at 40/60. It never feels like a pendulum, but it does give an eagerness to turn not found in the others. When exiting turns, the weight in back can be felt pulling the car around, but because everything is so compact near the center, it never feels as if it could get away from you.

The Lotus also takes full advantage of being a smaller vehicle in every way it can. Smaller brakes, wheels and tires all mean less rotating and unsprung mass. What most people don't consider is the much smaller gyroscopic effect of the smaller, lighter tires and wheels. It adds to the already amazing feedback, allowing the car to transmit even smaller nuances in tire/road interface. The giant rubber found on the BMW and Porsche allows for huge amounts of grip, but also numbs steering feel. All that mass just takes the edge off what the tires are doing. -Michael Febbo

Natty tread

Both the Porsche and the Lotus were on factory original tires for the test. The Porsche was on Pilot Sport 2s--one of our favorite tires for fast yet still surprisingly comfortable driving. The Lotus wears Yokohama A048s specifically designed and tuned for this application. The BMW, our long-term tester, had recently received Nitto Invos, which replaced the worn OEM Continental Sport Contacts. The Nittos provided an equal level of grip with a little less noise and improved ride quality.

They performed flawlessly during the canyon running and on the highway. The factory tires led some staffers to believe the car was equipped with run-flats. The Nittos traded the razor-sharp turn-in of the OEM rubber for a touch less sidewall stiffness, yet they still provided accurate feel and were a little more predictable than expected.

The Cayman's PS2s were as grippy and as comfortable as we remembered. It didn't feel as though they had the same high-speed stability as the other tires, but they were definitely the quietest.

The Yokohamas on the Lotus are thinly disguised race tires. It was interesting to drive in different conditions, because the tires really responded well to heat. During slower driving, the tires were slightly cooler and the car moved around a bit more. As temperatures built up with faster driving, the tires kept getting stickier. For race-spec rubber, they provided highly controllable breakaway.

Lotus advises owners not to use anything but the OEM tire on the car. The Exige, being as light as it is, will have trouble generating enough heat to get the most out of other tires. Porsche has a numbers of tires it approves. BMW is a little more open in tire choices but recommends owners stick with tires that meet speed and load indices of the factory equipment.-Michael Febbo