Toyota Motor Corp. 3.5L DOHC V-6
By Bill Visnic WardsAuto.com, Dec 20, 2006 9:01 AM

The format of the Ward’s 10 Best Engines competition rewards exotic or extravagant engineering that is beyond the competitive norm.

Winning its second consecutive 10 Best Engines award with the 3.5L DOHC V-6 used in the Lexus IS 350 sport sedan, Toyota Motor Corp. has no difficulty scoring top marks in the realm of special technical effort.

Direct-injection gasoline technology no longer is new or unique in the U.S. DIG systems can be found on numerous engines powering vehicles in a wide range of prices. But Toyota, with the 2GR-FSE V-6, adds an intriguing extra layer by blending a more-conventional port-injection system with DIG to optimize the advantages of both fueling designs.

In low- and part-load conditions, each cylinder’s direct- and indirect-injection fuel injectors are used according to the desired performance: emissions reduction, low-speed torque enhancement and reduced fuel consumption.

Variable valve timing and a variable-length intake manifold assist in creating the intake-mixture formation desired from both fueling systems to generate the ideal engine operation according to that moment’s engine load.

That sounds great in the lab, but on the road, the 2GR-FSE also delivers superb drivability and eye-opening performance. Its 306 hp ties the output of Nissan Motor Co. Ltd.’s new-generation 3.5L DOHC V-6, but the Toyota V-6’s 277 lb.-ft. (376 Nm) of torque surpasses even the thrusty Nissan V-6 for outright class leadership.

Toyota's 3.5L DOHC V-6 employs unique fuel-injection design.

Moreover, Toyota’s V-6 has sparkling throttle response, using DIG’s torque-enhancing characteristics to pull hard from virtually every engine speed – and it all comes with a large dose of Lexus-typical mega-refinement.

“So quiet, the acceleration is deceptive,” says Senior Editor Alisa Priddle. “An excellent example of DIG.”

“This one really checks off all the boxes,” gushes Ward’s AutoWorld Editor Drew Winter, noting the only complaint most 10 Best Engines judges can file: The Toyota 3.5L DOHC V-6, like most DIG engines, struggles to generate a satisfying and authoritative exhaust note.

We hear exhaust-component suppliers are hard at work on a fix for DIG engines of all layouts.

Another advantage of the dual-fueling systems, say Toyota engineers, is improved fuel economy. Many testers compliment the Toyota 3.5L DOHC V-6 for its thriftiness, highlighted by its class-leading 21-mpg (11.2 L/100 km) city and 28-mpg (8.4 L/100 km) highway fuel-economy ratings. One editor saw an overall average of 24 mpg (9.7 L/100 km) on a mixed-driving trip of several days.

While the aural emanations still could be more involving, Toyota and Lexus do indeed check off all the boxes here.

The 3.5L DOHC V-6 is a thrilling sport-sedan engine that compromises nothing in terms of refinement and fuel economy. It’s a technical achievement worthy of Toyota and Lexus’ high-flying reputation.

bvisnic@wardsauto.com