8 replies to this topic

[hansrobert]

I saw an article in an automotive magazine that stated the 2012 RX450h is now specified to run on 87 octane. Did anyone else see this stated anywhere and is it true? If true I wonder if the previous years can be converted? Any thoughts?

[richard4u]

I saw an article in an automotive magazine that stated the 2012 RX450h is now specified to run on 87 octane. Did anyone else see this stated anywhere and is it true? If true I wonder if the previous years can be converted? Any thoughts?

I HAVE BEEN RUNNING 87 octain in my 2007 rx400h runs great

[BobBass]

Like richard4u, I've been running 87 ethanolized gas in my '08 almost exclusively with no problems, not counting the possible lower MPG I might be getting.

As far as "conversion," you might as well forget about that. You'd probably have to change the cylinder heads, pistons, CPU, and who knows what else to achieve that.

[hansrobert]

I saw an article in an automotive magazine that stated the 2012 RX450h is now specified to run on 87 octane. Did anyone else see this stated anywhere and is it true? If true I wonder if the previous years can be converted? Any thoughts?

I HAVE BEEN RUNNING 87 octain in my 2007 rx400h runs great

I am a new 2011 RX450h owner. My first Lexus and my first hybrid. I have seen various posts on this forum about octane requirements. The owners manual says 91 octane is required. I have asked the salesman to ask the service deparment if this is a must with no straight answer. Some say they run 87 with no problem and I respect that experience. What I find frustrating is that I cannot get a straight answer as to the downside of using 87 octane. If 87 is just as good as 91 then why is 91 listed as a requirement and why has the 2012 RX450h required been changed to 87. Any thoughts appreciated!

[RX400h]

My guess is that your 2011's rated horsepower requires the use of premium fuel. The 2012 may be rated (horsepower, torque, and fuel economy) using regular fuel, which makes sense since most hybrids are rated to run on regular grade fuel.
Most higher-end vehicles made since the late 80s incorporate electronic knock sensors that will instruct the engine's ECU to retard timing if knocking/pinging is detected. It is because of these sensors that many vehicles can run on lower octain fuel than is recommended by the manufacturer.

[thelazydogsback]

I've never used anything but regular in my 400h - there's really no reason to pay the premium for, ah, premium.
The more expensive fuel is not likely to effect performance or economy except in very high compression racing engines. It may effect pre-ignition/knock and how the ICE starts/stops - it may help when the ICE does not stop running immediately when you're at a light, etc. (Hardly worth the price.)

I saw an article in an automotive magazine that stated the 2012 RX450h is now specified to run on 87 octane. Did anyone else see this stated anywhere and is it true? If true I wonder if the previous years can be converted? Any thoughts?

[RX400h]

Actually, it does affect performance. However, your style of driving will determine whether it makes a significant difference to you. If you decide to race a Porsche Cayenne or BMW X5, then yes, you will appreciate premium fuel in the tank.

[thelazydogsback]

I still doubt this very measurable in practice in the case of particular ICE in the 400h - especially given that when you put the petal to the metal the ICE is assisted by two electric motors all through the CVT.

Actually, it does affect performance. However, your style of driving will determine whether it makes a significant difference to you. If you decide to race a Porsche Cayenne or BMW X5, then yes, you will appreciate premium fuel in the tank.

[RX400h]

Horsepower from the ICE dominates acceleration at the upper end of the rev range. The electric motors produce greatest torque at 0 RPM, so while the level battery charge does make a difference in acceleration, octane rating and ambient temperature also play a role that can be felt when the throttle is held wide open.