I read your comments regularly in the Globe and enjoy them. However, one question that puzzles me is that a 2011 Toyota Highlander with a six-cylinder, 3.5-litre motor runs on regular grade gasoline as well as all Toyota 3.5-litre motors in the Camry, Sienna and RAV4. These are the same as my 2008 Lexus RX 3.5-litre motor which requires high-grade gasoline according to the owner’s manual. I do long-distance driving and have almost 50,000 kilometres on the odometer and have used regular-grade gasoline about two-thirds of my driving with no apparent difference in performance or fuel mileage. Can you please enlighten me, am I doing harm to my motor? I plan to drive my RX to at least 300,000 km. – Bev
No, you are not doing your engine any harm.
While all of these 3.5-litre engines (motors are electric) share the same basic architecture, they are tuned differently.
The engines used in the Toyotas produce 266-268 horsepower, slightly less in models where the exhaust may be more restricted by rear suspension layouts, while that in your Lexus is rated at 275. The slight difference is due to higher octane gasoline and the ability of the management system to advance timing slightly.
It accounts for regular gas by backing off the timing and a few horses escape the corral. I guess the thinking is that Lexus customers are less likely to be concerned with fuel prices.
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