Regular or Premium Gasoline Required?
Lexus Test Driver
Joined: Mar 2013
Posts: 5,449
Likes: 948
From: IL
Wow! This thread is really long for such a simple answer. RX350 runs on regular unleaded. Anything higher is just throwing money away. The car is not tuned for higher octane, so there will be no benefit from it. The RX450h recommends premium. You can get away with running lower octane, but to get the most out of your vehicle, use premium.
It's as simple as that.
It's as simple as that.
Driver
Joined: Mar 2017
Posts: 56
Likes: 3
From: CA
Wow! This thread is really long for such a simple answer. RX350 runs on regular unleaded. Anything higher is just throwing money away. The car is not tuned for higher octane, so there will be no benefit from it. The RX450h recommends premium. You can get away with running lower octane, but to get the most out of your vehicle, use premium.
It's as simple as that.
It's as simple as that.
Thread Starter
Advanced
Joined: Aug 2006
Posts: 644
Likes: 135
From: NJ
Then, aside from the debate in this forum about whether premium improves power/torque/mileage, a real benefit of using premium should be a cleaner engine, yes?
Lexus Test Driver
Joined: Mar 2013
Posts: 5,449
Likes: 948
From: IL
The recommended fuel relates to achieving the marketed and specified EPA mpg and hp torque numbers. It doesn't mean the engineers put ceilings on the timings. I'd be very disappointed if Lexus engineers are doing that.
if they said 87 "required" perhaps one could be sure there is a ceiling on the timings.
if they said 87 "required" perhaps one could be sure there is a ceiling on the timings.
No car states Regular Fuel Required, as higher octane will not harm the engine, just your bank account.
Lexus Test Driver
Joined: Mar 2013
Posts: 5,449
Likes: 948
From: IL
Intermediate
Joined: Jul 2006
Posts: 488
Likes: 24
From: ak
Pole Position
Joined: Jan 2005
Posts: 3,312
Likes: 542
From: Florida
The dealer fills you you tank with regular and you may continue to do so.
Lexus Test Driver
Joined: Mar 2013
Posts: 5,449
Likes: 948
From: IL
With you, it is. I'm now seeing why this thread is so long. Believe what you want. I can't stop you from wasting your money.
Racer
Joined: Feb 2017
Posts: 1,555
Likes: 345
From: Ontario, Canada
[QUOTE=615tpc;98385.if they said 87 "required" perhaps one could be sure there is a ceiling on the timings.[/QUOTE]
You are right! Lexus engineers did not put a ceiling, but they did pit a floor level, below which one shouldn't go and that's 87. Stands to reason that 87 being the absolute minimum 91 would be better, engineers did not say not to go above....octanes yet I'm always amazed at how people interpret this, they seem to read this minimum as a must and only.
You are right! Lexus engineers did not put a ceiling, but they did pit a floor level, below which one shouldn't go and that's 87. Stands to reason that 87 being the absolute minimum 91 would be better, engineers did not say not to go above....octanes yet I'm always amazed at how people interpret this, they seem to read this minimum as a must and only.
Driver
Joined: Aug 2016
Posts: 71
Likes: 24
From: Florida
There is a technical document on Tacoma World regarding the 2GR-FKS engine. Google it and you will see the valve advance maps and technical data. The exact programming is, of course, trade secrets, and not in the document. Direct injection engine technology has pretty much eliminated pre-ignition of gasoline compared to the standard days of port fuel injection -- I know the 2GR-FKS uses both, but when engine is warmed up, it uses mainly GDI and goes through a cleaning cycle via the PFI during idle periods.
Someone should just dyno their RX using 91+ and 87, unplugging the battery between runs to reset the sensor and on-board RAM. That way this discussion will actually have better data than a "butt-dyno". Right now it is conjecture on both sides.
Someone should just dyno their RX using 91+ and 87, unplugging the battery between runs to reset the sensor and on-board RAM. That way this discussion will actually have better data than a "butt-dyno". Right now it is conjecture on both sides.
