Unique to the IS is a pair of differently sized engines, for the first time in North America, which are now vee shaped instead of straight.
 |
| The new 2.5-litre V6 is quiet and refined, even with normally noisy direct injection on board. (Photo: Justin Couture, Canadian Auto Press) |
Reasons behind the latter switch are innumerable, but the prime motivation was to shed the heavy cast-iron Supra block for a lighter all-alloy design, plus a vee layout is more compact, allowing for a larger displacement capabilities, as well as allowing the motor to be positioned further back in the vehicle for better weight distribution.
Where I-6s offer the pinnacle of engine smoothness, promoted by none other than rival BMW, the IS follows the lead of Mercedes-Benz which dropped its inline
 |
| The IS 250's 204-hp V6 definitely gives off a seat-of-the-pants impression that the rumours of its horsepower rating being downplayed may be correct. (Photo: Hideo "Edge" Egashira, Lexus Canada) |
sixes years ago in place of a series of new V6 engines. Where we can chalk one up for Lexus, is in just how quiet and refined its new 2.5-litre V6 is, even with direct injection on board, a technology acclaimed for its performance-boosting abilities but panned for its inherent loudness. With the aforementioned D4-S direct injection system, dual variable valve timing, and dual overhead cams, the smaller 2.5-litre engine comes close to eclipsing the old IS 300's performance too, with an output of 204-hp and 184 lb-ft of torque, giving it an impressively high specific power ratio. Rumours have it that this value is downplayed, with the actual output being some 20 horses higher. It certainly gives off a seat-of-the-pants impression that the rumours may be correct.
