V10 off-limits for time being: LFA chief

The race-bred engine that is the heart of Lexus' new supercar is off-limits to the rest of the model range. That's the official line from the powerplant's designer, ex-F1 engine designer, Takamitsu Okamoto.

Okamoto, whose portfolio includes engines of the Le Mans Group C prototypes, Group B rally cars, CART turbo V8s and F1, says the hand-assembled V10 is simply too expensive to be used in other Lexus models.

The compact race-style dry-sumped V10 is assembled by motorcycle specialist Yamaha and features a block that is cast and machined by Toyota's own F1 operation in Toyota City in Nagoya, Japan.

The engine's design places oil, water and scavenger pumps at the rear of the engine for compactness. Ancillaries like the power steering and aircon units are mounted low on the front of the power unit to allow servicing.

Okamoto says the engine is actually smaller than the V8 used in Lexus' only other dedicated performance model, the IS F. But, he says, it is "many times more expensive to build".

This fact, rather than a lack of desire to leverage the engine's development cost, will limit the ten-cylinder's scope for use in further models, he says.

Internals used in the new Lexus engine include titanium rods and valves, and forged alloy slipper style pistons. The engine's rocker covers are magnesium and the headers are works of art in stainless steel. Instead of steel or alloy cylinder liners, the V10 takes a leaf out of motorcycle engineering text books and uses a 'thermal sprayed' cylinder coating.

Inspired by F1 engines, Okamoto says the new LFA powerplant has the potential to rev significantly higher than its current 9000rpm limit save for the "heavy" variable valve timing hardware.

In a race application, the engine would likely feature fixed cam timing which would dispense with the mechanism.

At 483Nm, its peak torque is substantial, though not in the league of cars like Benz's new SLS. That said, Okamoto says torque could be boosted if the engine was used in an application that demanded it.

No total development cost has been announced for the LFA program, though it's a fair guess to suggest it would number into the billions of dollars. Despite rumours to the contrary, Lexus sources say that at no time during its protracted five-year development cycle was the program suspended or its head count reduced.

Nonetheless, overall program boss, Haruhiko Tanahashi, admits the car faced "headwinds" and "crossed many mountains and rivers" to get to yesterday's official debut.

New Toyota boss Akio Toyoda's patronage, and his belief that the LFA is a halo car Lexus needs, appears to have been crucial to the car's fortunes.

Despite the high cost, however, Lexus insiders suggest even over a short two-year life span it's money well spent.

Lexus Australia boss, John Roca told the Carsales Network: "If you look it from a pure view of being a car, yes [it's a large investment for a one-off run]... But if you look at it from a brand statement... It's a statement that says we can produce that type of vehicle."

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