Is it true that the HS recommended fuel is standard 87 Octane?
Is it because it's somewhat of a glorified Prius?
Or is it because Toyota's engines are in Lexus's Vehicles?

 

On the HS 250h brochure it does state for the fuel requirement of regular unleaded, 87 octane but I'm sure it'll run better with premium unleaded gas...

 

yes sir it runs on 87

 

The HS engine is a so-called "Atkinson cycle" engine, like the Prius. Keep in mind that the analogy is best served as a "glorified Camry hybrid" rather than a "glorified Prius" as the HS shares the same gasoline engine as the Camry hybrid.

Running a higher octane fuel in the HS will not get you better mileage or performance. The engine is not designed to adjust timing based on octane like all other non-Atkinson Toyota/Lexus engines. While all other Lexus vehicles state that premium fuel is required, you can still use regular 87 octane gas and the fuel sensor will adjust the timing to compensate for the lower octane, resulting in a marginal loss of HP and economy. The inverse is true for all Toyota engines from about 2005 and on: while 87 octane is recommended, putting in premium fuel will result in marginally higher economy and HP.

Source: me. I work for Lexus and Toyota.

 

yes this octane rating thing has been done to death already, putting more is not going to give you any benefit.

I would suspect that it runs on 87...kinda pointless to have an economical car that uses premium

 

Kurticus, one of the reasons I'm considering the HS is founded on 2 issues: (1) I drive an '08 RX350. During a gas crisis several months ago, you couldn't obtain premium fuel in NC for several weeks. So I fear the same thing may occur in the future (Iran, global recession blah blah). (2) Although I know I could use 87 octane in the RX, I've been told by several people that eventually it will cause the RX to have engine problems, which Lexus will discover during repair; they will know I've been running it on regular gas, which will then void my warranty.

Any truth to the engine problems/voiding of warranty if using regular?

 

Once again, running regular unleaded in your 08 RX isn't the end of the world.

 

why complain about 87? what you want it to run on 93? my only options here are 87 89 and 93 in CT. and lexus recommands i run 93 in my is350