Test Drive: 2008 Lexus IS-F car review, What IS is

August 30, 9:38 AMAuto Review ExaminerJohn Matras

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What this V-8-powered Lexus sport sedan is not: a Lexus IS500. What it is: a Lexus IS-F, powered by a 5-liter V-8. One might have expected Lexus to follow its familiar naming rubric, based on the model’s chassis and displacement. But the IS-F is anything but a familiar Lexus.

Instead, Lexus is borrowing a page from the playbooks of Mercedes-Benz, BMW and Cadillac with, respectively, their AMG, M and V performance brands-within-a-brand. For Lexus, the new designation is “F” and the IS is the first morel to wear that designation.

Briefly, the IS-F is Lexus’ compact IS sport sedan equipped with a buttoned-down sport suspension but especially hand-built high-performance V-8 engine and eight-speed manually-shiftable automatic transmission.

Working with the skunks  It’s the product of the imagination of Lexus engineer Yukihiko Yaguchi who was able to avoid the usual committee-approved and sanitized car. Instead of the typical 1,000 to 1,500 member big comapny product development team, Yaguchi-san worked with at any given time 100 to 300 staff in a “skunk works” type atmosphere, officially beginning in the spring of 2004.

To wrest more power from the new Lexus UR-series V-8 engine that debuted in the Lexus LS460, Yaguchi enlisted help from Yamaha’s aftermarket project division, taking advantage of Yamaha’s F1 engine program. Though the engine, designated 2UR-GSE, benefits from the hybrid LS600h’s five-liter block, including the same bore and stroke dimensions, the F engine is more than just bigger. Starting at the top, the five-liter F has a cast-aluminum intake manifold and new Yamaha-developed cylinder heads.

The Lexus LS-F’s double overhead cam engine has light-weight titanium intake valves, allowing high rpm performance with a high-lift valve train, with electric motor-controlled intake and hydraulically adjusted exhaust valve timing. The engine has a combination of port and direct (into the combustion chamber) fuel injection, also found on the LS600h, LS460, GS350 and IS350. Direct injection, says Lexus, adds more torque at low rpm, while port injection aids efficiency at higher engine speeds Add the usual fine tuning of air flow into and out of the engine, plus a compression ratio of 11.8:1, and the engine is rated at 416 horsepower at 6600 rpm and 371 lb-ft of torque at 5200 rpm. (And for those who are counting, EPA estimates of 16/23 mpg city/highway).

Scavenging your head  A feature direct from racing engines is its “head scavenge oil pump.” High lateral g-forces during cornering can force lubricating oil into the cylinder heads of a vee engine while simultaneously moving oil in the oil pan away from the main oil pickup. The head scavenge oil pump moves the centrifugal force-trapped oil down to the oil pan where it can be picked up by the main oil pump to maintain the flow of oil to the engine.

Rather than the typical air-cooled oil cooler, the 2UR-GSE cools engine oil with the engine’s coolant for a more consistent oil temperature. (It also warms the oil to operating temperature more quickly).

The IS-F’s 8-speed transmission is not an eletronically-shifted manual transmission but rather a conventional automatic…of sorts. Though with a few more ratios. It’s as compact as the 6-speed autobox in IS350 and GS350 and about the same weight, but behaves as much like a manual transmission as any clutchless manual transmission from other makers. In manual mode, shifts are faster, claims Toyota, than the Ferrari F430’s. With four disc clutches, two disc brakes and one one-way cutch, power is transferred in manual mode through the transmission with a solid non-fluid connection, using the torque converter only in first gear at slow speeds. The transmission also has all the rpm-matching features of clutchless manual transmissions.

The IS-F isn’t just a hot drivetrain, however. The front spring and shock absorber rates raised 90 percent and rear increased 50 percent respectively. Body roll in cornering is decreased with stiffer front and rear anti-roll bars. Components, such as high-rigidity, high-precision hub unit bearings, were upgraded from standard for improved cornering performance. The ride height reduced by .8 inch.

Wheels with direction  The IS-F has directional 19-inch wheels, with spokes shaped like fan blades to pull air away from the brakes. Forged by BBS, they’re about 40-percent lighter than cast wheels would have been. They’re also about three and a half times more expensive. Watch out for those potholes.

The rear tires are wider than the front for improved handling and road-holding, front 225/40R19 and rear 255/35R19. The rear track of the IS-F is actually narrower than lesser IS model because the wider tires and lower ride height require more inward offset—thus making the centerline of the tires—where track is measured—closer to the center of the car. So much for raw numbers.

We often complain, by the way, about gaps between the tire circumference and the well-well-opening. Not so with the IS-F, whose rear tires snuggle up inside the rear fenders. Forget fitting chains…as if anyone had plans to mount a snowboard rack on an IS-F anyway.

In addition to having to winter over in a warm garage somewhere, a Lexus IS-F has to stop sometime, or at least slow down, and for that the IS-F is well equipped with Brembo-built, Lexus-spec’d brakes. The front stoppers have six-piston calipers with three caliper diameters and drilled and pillar-fin ventilated 14.2-inch diameter discs. Front discs are matched by 13.6-inch diameter discs, drilled and pillar-fin ventilated ,with two-piston calipers at the rear.

Not surprisingly, you can’t wrap the standard Lexus IS body around all this stuff. While the rear wheels were snuggled inside the standard fenders, the front fenders were flared to accommodate the wider tires and with as inch more front track, adding two inches of width at the front of the vehicle, compared to the 2008 IS350. The wider front fenders shows up in vents (to allow hot underhood air to escape) just ahead of the front doors. Lexus claims the vents are functional, passing heated air from under the hood. Our gut reaction is that they don’t look deep enough to make much of a difference, but then what does our gut know?

Bigger nose  The Lexus IS-F also grew 3.35 inches in length, adding three inches up to fit the V-8 in an engine bay originally designed for a V-6. Lexus designers were able to come up with a new front fascia that maintains the overall look of the basic IS but with larger lower grilles and functional brake scoops, plus a lower air dam. The overall look is still Lexus IS…but a very intense IS.

The wheelbase is the same as the base model, but despite the larger engine, weight balance comes out a respectable 54/46 front-to-rear. The curb weight of the IS-F is a relatively svelte 3,780, compared to the similarly-powered Audi RS4 which weighs slightly less than 4,000 pounds.

Lexus claims 0-60 mph in 4.6 seconds. Well, by diggity, we’ll bet they’re right. Lexus also says the IS-F is governed to a top speed of 170 mph, and again, we don’t doubt it. Asked how fast the IS-F would go with the governor turned off, a Lexus rep just mumbled something and looked the other way. We’re not sure whether that meant the car was limited to that speed because Lexus knows it won’t go much faster and putting a “limit” on it, um, leaves more to the imagination.
One needn’t imagine very much with the Lexus IS-F, however. Nail the throttle and 416 horses nail back. Does it accelerate hard? Oh, yes. Definitely yes. Lexus claims it turns the the quarter-mile in 13.0 ticks of the clock.

It sounds great doing it, too. That’s no accident, with Lexus engineers spending considerable time getting the sound just right, much like Mazda did with the Miata. Yaguchi-san recognized the importance not only of exterior sound but also what’s heard in the passenger compartment. So while the exhaust sound increases linearly over the engine’s operating range, the intake sound—particularly inside the vehicle—takes a bump at about 3500 rpm, which is where Lexus says “ordinary driving” changes to “performance driving.”

It works. Accelerate past 3500 rpm, even at part throttle, and there’s a distinct increase in the in-cabin sound level. At Yaguchi’s performance-driving rpm it’s simply an intoxicating sound track for the activities at hand.

Kachunk  The next question, however, is how well the unique Lexus performance automatic transmission works. Well, left to its own devices, the transmission shifts smoothly at light throttle around town. But crack open the throttle, even in full automatic mode, and each shift is accompanied by a hard kachunk as the engine pauses momentarily and the next ratio slams home. Forget cushy autoshifter ratio changes. The direct clutches, um, emphatically override the torque converter for—if nothing else—a hard-edged credibility a Lexus cavorting in the high-performance playground.

But shift—so to speak—into manual-shift mode and gear changes at part throttle are rewarded with a big swat from behind. Subtle it ain’t. The transmission won’t shift automatically in this mode. Run up against the redline and you’ll bounce against the rev limiter. Watch the tach and flip the paddle at the right time, however, and the transmission bangs through gears like Don Prudhomme (who, if you have to ask, is this famous drag racing guy). The IS-F also has a shift warning beep, and if you do it right, it will sound momentarily with every shift. At least it did for us. And we were obviously doing it right. Because we are definitely us.

Sweepers at 120?  Ride is firm-to-hard. The IS-F has no adjustable shocks or other compromises. Just driving a Lexus IS-F is presumably prima facie evidence that a cushy ride isn’t necessary or perhaps even desired even part-time. Our preliminary impression of the IS-F’s handling is razor responsiveness and it feels like, if we were given full opportunity, the car would prove to be a superb handler. However, Lexus afforded us only public roads that were primarily straight with only a few sweepers that we suspect would require a speed of 120 before taxing the IS-F’s cornering capabilities. Simply put, the owner who doesn’t take the IS-F to track days is not getting his (OK, or her) money’s worth.

As hard-edged as much of the car is, the interior is still Lexus, nicely finished and well thought out. Anyone familiar with standard IS models will be familiar with the IS-F. New front seats, however, are deeply pocketed for lateral support in during hard cornering (hard enough, say, to trap oil under the valve covers—see above). However, unlike many, uh, performance-enhanced sedans, Lexus hasn’t forgotten the backseat passenger. A new rear seat designed by Lexus for the IS-F is belted for two and has the deepest side bolsters ever seen in the rear of a sedan. Very un-Lexus-like.
But then again, so is the rest of the 2008 Lexus IS-F. Lexus promised to make this the Lexus you thought they’d never make. Indeed, we would have been surprised by an IS500. Instead, we’re flabbergasted by the IS-F (and you might be impressed by a base price of $56,000 and EPA estimated 16/23 mpg city/highway on premium fuel).

But we’d be quite happy to take our time getting familiar.

Illustrations: 2008 Lexus IS-F, courtesy Lexus.