View Poll Results: What gas do you put into your 2RX?
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Do you need Premium Gas in the 2RX (merged discussion threads)
01-10-12, 04:52 PM
#526
Driver School Candidate
Join Date: Jan 2012
Location: pa
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I'm surprised nobody mentioned that his trip home may have involved more uphill driving - indicating that the trip back down to the dealer would have had a greater amount of downhill driving, causing the fuel efficiency difference.
Personally, after 8 months of driving, I average 23-24 MPG in my 04 RX 330 in mixed driving using 93 octane, and 19-20 MPG using 87 or 89 octane. Same gas station next to my house is used for all fueling. Ethanol of up to 10% is in any octane of fuel from this particular station. I calculate fuel economy manually with gas station receipts and the trip odometer...but it's usually within 5% of the vehicle's computer readout. The best economy I've gotten was 27.3 MPG from a 200 mile round trip, mainly highway driving at 75 MPH, with 93 octane fuel. Similar weather conditions and 87 octane fuel gave me 22.8 MPG on the same route.
My occupation partially involves seeing many different fleet and personal vehicle historical records which includes their fuel economy records. I typically notice a 7-10% MPG increase for any vehicle's fuel records when they've used premium fuel.
Personally, after 8 months of driving, I average 23-24 MPG in my 04 RX 330 in mixed driving using 93 octane, and 19-20 MPG using 87 or 89 octane. Same gas station next to my house is used for all fueling. Ethanol of up to 10% is in any octane of fuel from this particular station. I calculate fuel economy manually with gas station receipts and the trip odometer...but it's usually within 5% of the vehicle's computer readout. The best economy I've gotten was 27.3 MPG from a 200 mile round trip, mainly highway driving at 75 MPH, with 93 octane fuel. Similar weather conditions and 87 octane fuel gave me 22.8 MPG on the same route.
My occupation partially involves seeing many different fleet and personal vehicle historical records which includes their fuel economy records. I typically notice a 7-10% MPG increase for any vehicle's fuel records when they've used premium fuel.
01-11-12, 08:39 AM
#528
Minimum MPG 17.2
Maxumim MPG 28.7
Average MPG 22.9 over life of vehicle
If you study the attached graphic you can see a couple interesting things. These MPG numbers are measured and not computer indicated.
1. My city/rural driving MPG improved markedly after the transmission reflash and I put new tires on the vehicle. There was no apparent change to my freeway MPG.
2. I take many long (1,500 mile) cross country trips where I set the cruse at 70-75 and run until I need to gas up again. I take the same freeway routes for these trips so I get a reasonably good testbed for evaluating MPG. I have have gotten the highest mileage when I run premium in my RX. I get good but less mileage with regular gas in the tank but this is only apparent on freeway trips. In the city/rural driving I don't SEE any change but I do FEEL the added power.
01-11-12, 09:58 AM
#529
Well, data is data. Must say very convincing.
01-11-12, 10:20 AM
#530
Lexus Champion
my millage rite now is around 17-17.5. And when it gets real cold out i.e 25degrees. It drops down to 16.5. On Premium fuel none the less. Summer, I get anywhere from 19-20 all around millage. Same driving.
01-11-12, 08:45 PM
#532
Having grown up in PA and gone to college there I am familiar with many sections of the state. For example, when I would go to Penn State on the way back it would pretty much be all downhill for miles and miles. Used to try to see how long I could coast before needing to use the gas.
01-11-12, 09:55 PM
#533
Unless your regular is an (evil) ethanol blend and your premiun is not an ethanol blend (and your tank was empty when you put the premium in), what you describe CANNOT be a consequence of using premium. The BTU content of the two fuels is identical. Premium will have higher octane and if you have a high comprerssion engine that you are flogging, it will perform better than it would with regular with the ignition timing "bumping off" the knock sensor. Premium may also have a better detergent package, but you would have to have a pretty dirty engine (from bad regular use) for that to make a difference and it would not happen as quickly as you describe.
What you describe cannot happen. Sorry.
- nopcbs
What you describe cannot happen. Sorry.
- nopcbs
Actually, it can and it does happen... I will try to explain...
As a general rule, you can make more power by advancing ignition timing. Advance ignition timing too far and you will get knock. Use of a higher octane fuel will allow more ignition timing, thus more power per combustion event... More power per engine cycle with no more fuel used means that you can relax your foot a couple percent on the throttle, meaning less fuel used to make the same power...
Essentially, the biggest deciding factor as to what octane fuel an engine requires is how much ignition advance (in combination with compression ratio) the engine is tuned for. Detune it a little and you can run less octane fuel... All new car engines do this automatically by listening for knock. They sense knock (due to anything, including low octane fuel), and they retard engine timing...
Great example - tuning a EVO - 28 psi boost, huge injectors, etc... base tune, not a lot of timing... made decent horsepower, 470ish range. added 3-7 degrees of timing (depending on where in the map), and the car made just over 500 hp... Since more power is available, you can run less throttle, which means less fuel consumption to make the same power... Even at a cruise speed, you can make the same power with less fuel...
01-12-12, 06:42 AM
#534
Lexus Champion
Actually, I thought about that and looked into it. Am familiar with approximately where lexus114 is located and exactly where the dealership is. So, I put the information into Google Earth. The difference in altitude was only a few feet along the route. Nothing that could make a difference.
Having grown up in PA and gone to college there I am familiar with many sections of the state. For example, when I would go to Penn State on the way back it would pretty much be all downhill for miles and miles. Used to try to see how long I could coast before needing to use the gas.
Having grown up in PA and gone to college there I am familiar with many sections of the state. For example, when I would go to Penn State on the way back it would pretty much be all downhill for miles and miles. Used to try to see how long I could coast before needing to use the gas.
Pretty impressive their dude!
01-12-12, 07:15 AM
#535
Lexus Champion
Actually, it can and it does happen... I will try to explain...
As a general rule, you can make more power by advancing ignition timing. Advance ignition timing too far and you will get knock. Use of a higher octane fuel will allow more ignition timing, thus more power per combustion event... More power per engine cycle with no more fuel used means that you can relax your foot a couple percent on the throttle, meaning less fuel used to make the same power...
Essentially, the biggest deciding factor as to what octane fuel an engine requires is how much ignition advance (in combination with compression ratio) the engine is tuned for. Detune it a little and you can run less octane fuel... All new car engines do this automatically by listening for knock. They sense knock (due to anything, including low octane fuel), and they retard engine timing...
Great example - tuning a EVO - 28 psi boost, huge injectors, etc... base tune, not a lot of timing... made decent horsepower, 470ish range. added 3-7 degrees of timing (depending on where in the map), and the car made just over 500 hp... Since more power is available, you can run less throttle, which means less fuel consumption to make the same power... Even at a cruise speed, you can make the same power with less fuel...
As a general rule, you can make more power by advancing ignition timing. Advance ignition timing too far and you will get knock. Use of a higher octane fuel will allow more ignition timing, thus more power per combustion event... More power per engine cycle with no more fuel used means that you can relax your foot a couple percent on the throttle, meaning less fuel used to make the same power...
Essentially, the biggest deciding factor as to what octane fuel an engine requires is how much ignition advance (in combination with compression ratio) the engine is tuned for. Detune it a little and you can run less octane fuel... All new car engines do this automatically by listening for knock. They sense knock (due to anything, including low octane fuel), and they retard engine timing...
Great example - tuning a EVO - 28 psi boost, huge injectors, etc... base tune, not a lot of timing... made decent horsepower, 470ish range. added 3-7 degrees of timing (depending on where in the map), and the car made just over 500 hp... Since more power is available, you can run less throttle, which means less fuel consumption to make the same power... Even at a cruise speed, you can make the same power with less fuel...
And less combustion/exhaust temps too. Helps the cat converters, and air fuel ratio sensors live a longer happier life.
10-05-12, 05:55 PM
#536
Gas grade for 2009 RX
Hello
The manual says to use gasoline grade of 91. With prices skyrocketing out here in California, would it be OK to go to 89 or 84? Was wondering what it would do to the engine.
Also, do you know if this model uses a special synthetic oil, or just standard oil?
Thank you.
The manual says to use gasoline grade of 91. With prices skyrocketing out here in California, would it be OK to go to 89 or 84? Was wondering what it would do to the engine.
Also, do you know if this model uses a special synthetic oil, or just standard oil?
Thank you.
10-05-12, 06:30 PM
#537
Hello
The manual says to use gasoline grade of 91. With prices skyrocketing out here in California, would it be OK to go to 89 or 84? Was wondering what it would do to the engine.
Also, do you know if this model uses a special synthetic oil, or just standard oil?
Thank you.
The manual says to use gasoline grade of 91. With prices skyrocketing out here in California, would it be OK to go to 89 or 84? Was wondering what it would do to the engine.
Also, do you know if this model uses a special synthetic oil, or just standard oil?
Thank you.
As for oil, plain old dino oil will suffice for your 5K oil change interval. From the Owner's Manual:
10-05-12, 06:47 PM
#538
Thank you so much!!!
Believe you mean 87 octane and not 84. Still, would stick with 91. The 2nd Generation RX350 engine is particular to its fuel requirements. Putting in a lower octane fuel will cut performance and fuel economy to the point where it is not worth doing.
As for oil, plain old dino oil will suffice for your 5K oil change interval. From the Owner's Manual:
Attachment 259997
As for oil, plain old dino oil will suffice for your 5K oil change interval. From the Owner's Manual:
Attachment 259997
10-06-12, 07:25 AM
#539
Driver School Candidate
Join Date: Oct 2012
Location: GA
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It's a Toyota engine. Designed for the lowest common denominator Camry driver. It'll go 50k without an oil change. (total joke....don't try this)
You can use any grade fuel, but using lower octane will cause the ECU to advance or retard ignition accordingly to protect the engine from pre-detonation and knock. You'll lose 5-10 hp using a lower grade which, as someone else said, can adversely affect fuel mileage. Around here it's a $0.30 difference between 87 and 93 octane. With a 19 gallon tank, if you ran it bone dry you'd be saving a whopping $6 a tank. If you figure an average 15k a year that's 750 gallons a year at 20mpg combined. That's $225 a year. If that's going to break you, you probably shouldn't be driving an RX.
You can use any grade fuel, but using lower octane will cause the ECU to advance or retard ignition accordingly to protect the engine from pre-detonation and knock. You'll lose 5-10 hp using a lower grade which, as someone else said, can adversely affect fuel mileage. Around here it's a $0.30 difference between 87 and 93 octane. With a 19 gallon tank, if you ran it bone dry you'd be saving a whopping $6 a tank. If you figure an average 15k a year that's 750 gallons a year at 20mpg combined. That's $225 a year. If that's going to break you, you probably shouldn't be driving an RX.
10-06-12, 10:42 AM
#540
It's a Toyota engine. Designed for the lowest common denominator Camry driver. It'll go 50k without an oil change. (total joke....don't try this)
You can use any grade fuel, but using lower octane will cause the ECU to advance or retard ignition accordingly to protect the engine from pre-detonation and knock. You'll lose 5-10 hp using a lower grade which, as someone else said, can adversely affect fuel mileage. Around here it's a $0.30 difference between 87 and 93 octane. With a 19 gallon tank, if you ran it bone dry you'd be saving a whopping $6 a tank. If you figure an average 15k a year that's 750 gallons a year at 20mpg combined. That's $225 a year. If that's going to break you, you probably shouldn't be driving an RX.
You can use any grade fuel, but using lower octane will cause the ECU to advance or retard ignition accordingly to protect the engine from pre-detonation and knock. You'll lose 5-10 hp using a lower grade which, as someone else said, can adversely affect fuel mileage. Around here it's a $0.30 difference between 87 and 93 octane. With a 19 gallon tank, if you ran it bone dry you'd be saving a whopping $6 a tank. If you figure an average 15k a year that's 750 gallons a year at 20mpg combined. That's $225 a year. If that's going to break you, you probably shouldn't be driving an RX.