Premium for 2010-2011 RX350? (merged threads)
Lexus Test Driver
Joined: Apr 2008
Posts: 1,363
Likes: 2
From: Ontario
With near $50k invested in my RX350, I think I will not take a chance and stick with "X-Men"s advice and fill with 92 Octane.
I was not planning to go with Regular grade (87)anyways, but the 10 cents diff per gallon diff from mid-grade 89 to premium 92 - is something I can happily sleep with.
Filled up yesterday with 92 Octane and same from this point on.
Interesting point to note - I dont know if its a psychological thing or not - but the RX350 drove quieter (engine noise) today, and I leaned on the acceleration a bit more just to "flush" it out.
I was not planning to go with Regular grade (87)anyways, but the 10 cents diff per gallon diff from mid-grade 89 to premium 92 - is something I can happily sleep with.
Filled up yesterday with 92 Octane and same from this point on.
Interesting point to note - I dont know if its a psychological thing or not - but the RX350 drove quieter (engine noise) today, and I leaned on the acceleration a bit more just to "flush" it out.
From a BTU perspective, there is no difference between 87, 89, 91, 93 or 94 octane gasoline, so technically, there should not be any difference in gas mileage or consumption. However, keep in mind that:
- some grades contain a percentage of ethanol, the higher the ethanol contain, the lower the gas mileage since ethanol has a lower BTU.
- timing and other tuning parameters get adjusted automaticaly, some of those will have an impact on consumption.
In Canada, the price difference between the different grades is anywhere from 17cents to 20cents a litre, so that is a $12 per fill up difference.
Lexus Champion
Joined: Aug 2006
Posts: 12,552
Likes: 278
From: Illinois
The 2011 Lexus ES350 use 87 octane and gets 268 HP, while the 2010 ES350 with the same engine was tune to use 91 octane and have 272 HP. Gas milage is the same for both year, 19/27 MPG.
So it looks like Lexus is in the process of de-tuning its engines to run on 87 octane to meet market demands, which I think its a smart move by Lexus.
So it looks like Lexus is in the process of de-tuning its engines to run on 87 octane to meet market demands, which I think its a smart move by Lexus.
The 268 hp lines up with Toyota models using the same engine on regular gas (Camry, Avalon, Venza, RAV4, Highlander and Sienna)
Last edited by LexBob2; Jun 7, 2011 at 11:20 AM.
Pit Crew
Joined: Feb 2010
Posts: 174
Likes: 4
From: West Palm Beach
If you think for instance, they just get the engine out of a Camry and drop it into the RX, your wrong the engines are different and are tuned different.
not to mention the 1000 lbs of weight the RX is holding over the Camry.
not to mention the 1000 lbs of weight the RX is holding over the Camry.
Lexus Test Driver
Joined: Apr 2008
Posts: 1,363
Likes: 2
From: Ontario
Engines are tuned differently, but the engine itself are the same across multiple products. Just look at the designation which for a major component is the same as a parts number. And by the way, manufacturing isn't done by taking parts from one car to another, but by having parts installed in the different assembly lines. The 1000 pounds extra for the RX is due to larger body, 4wd components, rear hatch door, etc.
Last edited by My0gr81; Jun 7, 2011 at 08:31 PM.
Racer
Joined: Apr 2011
Posts: 1,254
Likes: 81
From: IN
Not so much that lower octane is easy to burn than higher octane but the low octane ignites at a lower temperature and pressure. When you put low octane in a car that is design to use high octane, what’s happening is that the engine will try to compress the combustion chamber to its preset pressure and then fire the spark plug, but the low octane gas cannot go up to that pressure because it will ignite before it reach that pressure and before the spark plug fires. That is call a pre ignition, that pre ignition happens when valve and piston are out of position causing stress to those parts that they are not design for. It also cause carbon build up in the engine. After this pre ignition, the knock sensor will detect the noise and vibration and pull back the timing, making the spark plug fire earlier to compensate for the low octane. Since the RX's engine is design for 91 octane, the computer will start to advance the timing slowly until another pre ignition is sensed, at that point, it will once again pull back timing. This cycle happens over and over again for the life of your engine when you are using the incorrect octane.
Lead Lap
Joined: Sep 2009
Posts: 462
Likes: 4
From: NV
We have 87, 89 and 93 in Houston. When I fill up, I put in 93 octane for the first half of the tank. Then, I put in 89 octane for the rest of the tank. That should average 91 octane which is what recommended for the car.
Driver School Candidate
Joined: May 2011
Posts: 47
Likes: 0
From: FL
My last comment/update to this thread which I began.
After having switched to 92 Octane Premium fuel, vs the mid-grade 89, I can DEFINITELY state that my RX350 runs MUCH more smoother (engine sound/acceleration/idle) and also feel more responsive in terms of torque.
I wouldnt have believed it if I had not seen it first hand. FYI - mine is a 2011 RX350 AWD.
I clearly had some pinging going on before - when idling and I was outside of the vehicle, as compared to now on premium fuel.
I am willing to bet, I will see 1-2MPG better mileage with premium.
Anyway thanks for everyone's input.
After having switched to 92 Octane Premium fuel, vs the mid-grade 89, I can DEFINITELY state that my RX350 runs MUCH more smoother (engine sound/acceleration/idle) and also feel more responsive in terms of torque.
I wouldnt have believed it if I had not seen it first hand. FYI - mine is a 2011 RX350 AWD.
I clearly had some pinging going on before - when idling and I was outside of the vehicle, as compared to now on premium fuel.
I am willing to bet, I will see 1-2MPG better mileage with premium.
Anyway thanks for everyone's input.
Driver School Candidate
Joined: May 2010
Posts: 17
Likes: 0
From: MD
I am an electrical engineer not automotive but my logic is this:
The cross platform engine is just that, they make adjustments depending on the project but use the same basic layout. It just so happens they tuned this engine for a slight horsepower bump by using 91 oct. So in my case I have 89 and 93 available. The correct thing to do is mix half and half as the poster above suggested and get it to 91. I don't want to do that so I have to chose. Since both available fuels are a factor of 2 within 91 they will both not run as good as if it was 91. My guess: 89 runs with a slight loss of hp but better fuel mileage and 93 a bit more hp or at the 91 level but will burn more fuel. I have experimented with Both and am much happier with 89. I get 2 or more mpg and no noticeable power loss.
Just my 2c. Everyone will have different gas quality and environments they drive in.
The cross platform engine is just that, they make adjustments depending on the project but use the same basic layout. It just so happens they tuned this engine for a slight horsepower bump by using 91 oct. So in my case I have 89 and 93 available. The correct thing to do is mix half and half as the poster above suggested and get it to 91. I don't want to do that so I have to chose. Since both available fuels are a factor of 2 within 91 they will both not run as good as if it was 91. My guess: 89 runs with a slight loss of hp but better fuel mileage and 93 a bit more hp or at the 91 level but will burn more fuel. I have experimented with Both and am much happier with 89. I get 2 or more mpg and no noticeable power loss.
Just my 2c. Everyone will have different gas quality and environments they drive in.
Pit Crew
Joined: Sep 2011
Posts: 231
Likes: 2
From: FL
Premium for 2010-2011 RX350? (merged threads)
I just read that the 2012s will take the cheap gas no problem but I'm wondering about the 2010. I have never paid for premium gas and don't really want to do it now if I don't have to.
Driver
Joined: Sep 2011
Posts: 182
Likes: 0
From: VA
91 Octane (2011 model) vs 87 Octane (2012 model)
My 2011 RX-350 calls for the use of 91 or higher octane gas with the understanding that this vehicle will be able to accept 87 octane gas but the driver may experience performance degradations such as engine knocking or pinging or slightly less fuel economy. My understanding is that the 2012 model calls for the use of 87 octane gas.
IHas there been any engine modification in the 2012 model to be able to accept 87 octane gas better than the engine in the 2011 model? In other words, if I use the 87 octane gas in my 2011 model, will I get the same performance (or lack of performance) as using 87 octane gas in the 2012 model?
I am trying to understand whether there were any engine or fuel system design changes between the 2011 and 2012 models, or is the difference only in the owner's manual language pertaining to the gas octane requirements?
IHas there been any engine modification in the 2012 model to be able to accept 87 octane gas better than the engine in the 2011 model? In other words, if I use the 87 octane gas in my 2011 model, will I get the same performance (or lack of performance) as using 87 octane gas in the 2012 model?
I am trying to understand whether there were any engine or fuel system design changes between the 2011 and 2012 models, or is the difference only in the owner's manual language pertaining to the gas octane requirements?
Driver School Candidate
Joined: Apr 2011
Posts: 28
Likes: 0
From: ca
There is a lot of debate on this issue...Do a search
Personally, I use 91.
Its not much more, and I seem to get better gas mileage.
I have a mechanic that says to use the higher octane gas especially during smog checks.
Personally, I use 91.
Its not much more, and I seem to get better gas mileage.
I have a mechanic that says to use the higher octane gas especially during smog checks.
Lexus Test Driver
Joined: Aug 2011
Posts: 1,068
Likes: 11
From: California
i also have a 2011 RX 350 and im not worried about using unleaded (87)
and to answer your question, there's no changes with the engine between a 2011 and the 2012.
the only reason you WILL be getting a 270hp on a 2012 and not a 275hp ( 2011) is the change in the recommended fuel type.
i hope that clears up a lot of confusion.
and to answer your question, there's no changes with the engine between a 2011 and the 2012.
the only reason you WILL be getting a 270hp on a 2012 and not a 275hp ( 2011) is the change in the recommended fuel type.
i hope that clears up a lot of confusion.