LEXUS MADE THE MOST EFFICIENT ELECTRIC CROSSOVER ON SALE. HERE'S HOW

A certain combination of wheels, tires and powertrain can boost the range by dozens of miles.

Lexus and Toyota aren't known for their EV leadership. Both brands offer only one all-electric vehicle, and neither model offers particularly compelling range or charging specs. But when Lexus published efficiency data for the RZ 300e, our audience was shocked at how well it did. We asked Lexus for details on how the base model RZ quietly became one of the most efficient EVs on sale. 

If you're unfamiliar with the RZ lineup—I don't blame you—the base model 300e joined the lineup in 2024. Lexus was already selling an AWD RZ 450e, but the FWD model is way more efficient. The base model gets 125 MPGe, equivalent to roughly 3.7 miles per kWh including charging losses. That's more efficient than a Tesla Model Y. It's the most efficient EV SUV on sale, and one of the most efficient EVs period. 

Only a handful of 2024 model-year electric cars achieved a higher result. Three cars—the Hyundai Ioniq 6, Lucid Air and Tesla Model 3—in a total of seven versions are more efficient.

The question of how the Lexus RZ 300e became so efficient is fascinating because the original 450e version is far behind at 107 MPGe (315 Wh/mi or 3.2 miles/kWh). Plus the Lexus is far more efficient than the Toyota bZ4x on which it is based, which gets 119 MPGe in the EPA cycle. That's an inversion of what we typically expect: Luxury vehicles are heavier, and therefore usually less efficient than their mainstream counterparts. 

InsideEVs asked Lexus/Toyota to confirm the RZ 300e's results, and about why it's so much more efficient than the 450e. Lexus spokesperson Laura Finley confirmed 125 MPGe as the correct rating. As it turns out, there are several reasons why the 2024 Lexus RZ 300e uses less energy than the 450e.

First of all, this version has a single-motor, front-wheel drive powertrain making 201 horsepower, compared to the dual-motor, all-wheel-drive 450e that produces 308 hp. This one change removes some weight and reduces the axle friction from the rear e-axle. The RZ 300e's base curb weight is 4,277 lb, while the RZ 450e weighs in at 4,564 lb.

Another efficiency boost comes from the front e-axle inverter. In the RZ 450e, the inverter semiconductor is made out of silicon (Si). In the RZ 300e, Lexus uses a silicon carbide (SiC) semiconductor, which is more efficient. I'd guess this change improves efficiency by a few percent. It'll be interesting to see whether Lexus brings the SiC-type semiconductor to the AWD version in the next update.

For now, the SiC is unique for the RZ 300e. It's not used in the FWD version of the Toyota bZ4X, which may explain that model's lower efficiency rating.

Finally, the Lexus RZ 300e has different wheels and tires than the AWD version. The rear tire width is 235 mm (the same as the front) instead of 255 mm. On top of that, the 300e has a higher factory tire pressure: 42.1 psi instead of 33.4 psi.

The combination of the changes resulted in a quite significant efficiency improvement. The Lexus RZ 300e gets a slightly bigger battery, too—72.8-kilowatt-hours, instead of 71.4-kWh in the AWD—but that's a very small change (2%). The range improves by over 17% from 220 miles in the 450e to 266 miles in the 300e, so it's clearly more than just the battery. 

As the RZ shows, there are many small changes you can make to an EV to get a big range boost. If other manufacturers take note, hopefully, we'll soon have more 120+ MPGe SUVs to choose from. 

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See also

• 2024 Ford Mustang Mach-E: A Bit More EPA Range, Improved Efficiency
• The Number Of EVs With 300-Mile-Plus Ranges Is Skyrocketing
• The 2024 Lucid Air Has Up To 516 Miles Of Range, Outstanding Efficiency
• Tesla Model 3 Performance Will Exceed 300 Miles Of EPA Range

2024-06-24T18:27:23Z dg43tfdfdgfd