Premium gas for 2016 RX 450h?
02-23-18, 09:06 PM
#31
I have a RX450h and use 87 octane with no problem. The salesman told me that I could use 87 as that is what the dealer gives you when you pick up the car with a full tank, and the dealer only puts 87 in all of their demo and loaner cars. Have not had any lack of engine performance or noise.
87 is not an option.
Hopefully your salesman is mistaken.
02-23-18, 11:21 PM
#32
03-01-18, 08:29 AM
#33
Here's something Interesting - re: 87 vs 91 octane
So, I decided to try 87 octane (from Costco as well as from Shell), and compare it with Costco 91 and Shell 91 octane fuel.
Since moving to 87, I have *better* mpg than with Premium! Performance seems about the same but mpg is definitely up.
Any brand of 91 octane, I averaged 27mpg. With 87 octane, I'm consistently getting 29.5 - 30mpg.
Weird. I would of expected the exact opposite.
-aki
Since moving to 87, I have *better* mpg than with Premium! Performance seems about the same but mpg is definitely up.
Any brand of 91 octane, I averaged 27mpg. With 87 octane, I'm consistently getting 29.5 - 30mpg.
Weird. I would of expected the exact opposite.
-aki
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Geekteach (12-18-19)
03-01-18, 08:46 AM
#34
So, I decided to try 87 octane (from Costco as well as from Shell), and compare it with Costco 91 and Shell 91 octane fuel.
Since moving to 87, I have *better* mpg than with Premium! Performance seems about the same but mpg is definitely up.
Any brand of 91 octane, I averaged 27mpg. With 87 octane, I'm consistently getting 29.5 - 30mpg.
Weird. I would of expected the exact opposite.
-aki
Since moving to 87, I have *better* mpg than with Premium! Performance seems about the same but mpg is definitely up.
Any brand of 91 octane, I averaged 27mpg. With 87 octane, I'm consistently getting 29.5 - 30mpg.
Weird. I would of expected the exact opposite.
-aki
I saw and felt improvements when I compared premium vs regular as well.
03-01-18, 09:09 AM
#35
Your mileage is outstanding. Do you have the hybrid?
I saw and felt improvements when I compared premium vs regular as well.
I saw and felt improvements when I compared premium vs regular as well.
I just went over 5k on the odo.
For that little of a difference, I'm finding myself using sport mode a lot more. LOL
01-05-19, 03:04 PM
#36
Resurrecting this thread to mention that I saw an ad for a Lexus in a magazine the other day (sports car, not RX, but that's all I recall). The text mentioned horsepower and had an asterisk. Then, at the bottom, in tiny print, they said something like, "...quoted HP while using fuel with RON of 91..."
In other words, engine would be happy on regular gas, but you'd lose a bit of horsepower.
In other words, engine would be happy on regular gas, but you'd lose a bit of horsepower.
01-05-19, 04:11 PM
#37
Resurrecting this thread to mention that I saw an ad for a Lexus in a magazine the other day (sports car, not RX, but that's all I recall). The text mentioned horsepower and had an asterisk. Then, at the bottom, in tiny print, they said something like, "...quoted HP while using fuel with RON of 91..."
In other words, engine would be happy on regular gas, but you'd lose a bit of horsepower.
In other words, engine would be happy on regular gas, but you'd lose a bit of horsepower.
02-21-19, 10:38 AM
#38
Seems like every car forum has a "what gas should I use" thread. 
I just got a 16 RX 450h CPO. The Lexus dealership told me, on a number of occasions, that normal gas would be fine. But as stated above, the owners manual was very clear that premium 91 was expected. While it could run on normal - as all modern cars can - it would be less optimal and not recommended. The dealership sent me away with a tank full of regular and I was struggling to get 23-25 mpg. I put in the proper gas and I'm heading up where I should be (29-30).
I really hate it when dealerships do that. I'm not sure what they are trying to accomplish - new RX's of any flavor are $50-60k+, why would saving 20 cents per gallon be some kind of selling point? Car payments in that range would be well north of $6-700/mo but it's a selling point to save $2/tank? I don't understand, and they are going to hear about it when my survey arrives.
I've probably said this a dozen times across multiple car brand forums - I never saw the logic in buying a $50k+ luxury vehicle of any kind and then cheaping out on the gas to save a couple bucks per tank. Buy a Rav4 hybrid then. But to each his own I suppose - everyone has the right to do as they please. But when it comes to complicated modern engines I will religiously do two things - use the proper gas the engine was designed for and keep with with scheduled maintenance. If $4 / month matters that much, I'll buy less coffee.
I just got a 16 RX 450h CPO. The Lexus dealership told me, on a number of occasions, that normal gas would be fine. But as stated above, the owners manual was very clear that premium 91 was expected. While it could run on normal - as all modern cars can - it would be less optimal and not recommended. The dealership sent me away with a tank full of regular and I was struggling to get 23-25 mpg. I put in the proper gas and I'm heading up where I should be (29-30).
I really hate it when dealerships do that. I'm not sure what they are trying to accomplish - new RX's of any flavor are $50-60k+, why would saving 20 cents per gallon be some kind of selling point? Car payments in that range would be well north of $6-700/mo but it's a selling point to save $2/tank? I don't understand, and they are going to hear about it when my survey arrives.
I've probably said this a dozen times across multiple car brand forums - I never saw the logic in buying a $50k+ luxury vehicle of any kind and then cheaping out on the gas to save a couple bucks per tank. Buy a Rav4 hybrid then. But to each his own I suppose - everyone has the right to do as they please. But when it comes to complicated modern engines I will religiously do two things - use the proper gas the engine was designed for and keep with with scheduled maintenance. If $4 / month matters that much, I'll buy less coffee.
02-21-19, 11:41 AM
#39
Compression Ratio 13.0:1
Nuff said. While the knock sensor will protect you (provided it and the computer that handles it is working properly) it 100% is affecting the output of the engine away from the design specs.
https://jalopnik.com/heres-what-comp...-it-1819723873
riredale argues this point however due to our engine design.
Nuff said. While the knock sensor will protect you (provided it and the computer that handles it is working properly) it 100% is affecting the output of the engine away from the design specs.
https://jalopnik.com/heres-what-comp...-it-1819723873
riredale argues this point however due to our engine design.
Last edited by shadowmite; 02-21-19 at 11:51 AM. Reason: riredale's comment in other thread.
02-21-19, 11:45 AM
#40
Seems like every car forum has a "what gas should I use" thread.
I just got a 16 RX 450h CPO. The Lexus dealership told me, on a number of occasions, that normal gas would be fine. But as stated above, the owners manual was very clear that premium 91 was expected. While it could run on normal - as all modern cars can - it would be less optimal and not recommended. The dealership sent me away with a tank full of regular and I was struggling to get 23-25 mpg. I put in the proper gas and I'm heading up where I should be (29-30).
I really hate it when dealerships do that. I'm not sure what they are trying to accomplish - new RX's of any flavor are $50-60k+, why would saving 20 cents per gallon be some kind of selling point? Car payments in that range would be well north of $6-700/mo but it's a selling point to save $2/tank? I don't understand, and they are going to hear about it when my survey arrives.
I've probably said this a dozen times across multiple car brand forums - I never saw the logic in buying a $50k+ luxury vehicle of any kind and then cheaping out on the gas to save a couple bucks per tank. Buy a Rav4 hybrid then. But to each his own I suppose - everyone has the right to do as they please. But when it comes to complicated modern engines I will religiously do two things - use the proper gas the engine was designed for and keep with with scheduled maintenance. If $4 / month matters that much, I'll buy less coffee.
I just got a 16 RX 450h CPO. The Lexus dealership told me, on a number of occasions, that normal gas would be fine. But as stated above, the owners manual was very clear that premium 91 was expected. While it could run on normal - as all modern cars can - it would be less optimal and not recommended. The dealership sent me away with a tank full of regular and I was struggling to get 23-25 mpg. I put in the proper gas and I'm heading up where I should be (29-30).
I really hate it when dealerships do that. I'm not sure what they are trying to accomplish - new RX's of any flavor are $50-60k+, why would saving 20 cents per gallon be some kind of selling point? Car payments in that range would be well north of $6-700/mo but it's a selling point to save $2/tank? I don't understand, and they are going to hear about it when my survey arrives.
I've probably said this a dozen times across multiple car brand forums - I never saw the logic in buying a $50k+ luxury vehicle of any kind and then cheaping out on the gas to save a couple bucks per tank. Buy a Rav4 hybrid then. But to each his own I suppose - everyone has the right to do as they please. But when it comes to complicated modern engines I will religiously do two things - use the proper gas the engine was designed for and keep with with scheduled maintenance. If $4 / month matters that much, I'll buy less coffee.
02-21-19, 12:16 PM
#41
^ Totally understand everyone has different situations. 
Interesting note on 91 vs. top tier 91. I will more commonly use Safeway or Fred Meyer gas out of convenience but neither is top tier. I'll have to experiment and see what the difference is. An extra 4 mpg over a tank could be what, 40-44 extra miles? That's 1.3 or so gallons - I'm wondering if the better MPG would actually offset the extra cost of the gas (at least partially, if that 1.3 gallons was $6 or so).
Interesting note on 91 vs. top tier 91. I will more commonly use Safeway or Fred Meyer gas out of convenience but neither is top tier. I'll have to experiment and see what the difference is. An extra 4 mpg over a tank could be what, 40-44 extra miles? That's 1.3 or so gallons - I'm wondering if the better MPG would actually offset the extra cost of the gas (at least partially, if that 1.3 gallons was $6 or so).
02-21-19, 12:27 PM
#42
Lexus Champion
I understand your point, but in my area, the difference between 87 & 91 unleaded is about 50-60 cents per gallon. That’s approximately $9 per tank difference or about $900 per year. As I stated earlier, I agree with your logic. What I notice is my mileage flat out sucks if I don’t use top tier fuel. It doesn’t matter if I use 87 or 91, there’s no difference. When I use good top tier fuel, I can easily go from 22 mpg to 26 mpg. Unfortunately, I only have a choice of two top tier fuels here & one of those is Shell. Their fuels are easily 20 cents per gallon more than anyone else. I’ve given up on getting good fuel mileage with the 450. It’s just OK for a mid-size SUV & nothing to brag about.
02-22-19, 05:57 PM
#43
Shadowmite above had mentioned that I had made a comment on compression ratios in another thread. For what it's worth, here's what I wrote over there in response to a commenter's statement that premium fuel was needed due to a very high compression ratio:
-----------------------------
There's a bit more to the story these days, which is why your reasonable compression ratio rules-of-thumb probably don't apply.
Toyota hybrids use an Atkinson-style engine design, not the traditional Otto-cycle. They do so in order to gain an additional 5% or so improvement in efficiency. Efficiency comes from having a very high EXPANSION ratio, such that the engine gets as much energy out of the expanding charge as possible before opening the exhaust valve. In a traditional Otto engine that meant having a high COMPRESSION ratio also (both were locked together), which meant too-high cylinder BMEP and engine knock. But in the Atkinson, Toyota leaves the intake valve open for part of the upstroke, so the total charge at the time of ignition is reduced. This means less power but, again, more efficiency. My 2010 RX450h engine has 240HP versus about 270 for its Otto-cycle cousin, but in the hybrid we also have electric motors to assist, so in fact the hybrid car has more total HP than the cousin. Very clever.
So don't look at the expansion ratio to see if premium fuel is needed. It's not. The engine is a whole different animal. And, as already mentioned, every modern engine uses a knock sensor that will kick in if necessary.
Car manufacturers use the "premium fuel" tag to maximize the specs and EPA ratings. As long as you use high-quality regular fuel, the engine will be perfectly happy but you'll lose a few HP and a fraction of an mpg.
-----------------------------
There's a bit more to the story these days, which is why your reasonable compression ratio rules-of-thumb probably don't apply.
Toyota hybrids use an Atkinson-style engine design, not the traditional Otto-cycle. They do so in order to gain an additional 5% or so improvement in efficiency. Efficiency comes from having a very high EXPANSION ratio, such that the engine gets as much energy out of the expanding charge as possible before opening the exhaust valve. In a traditional Otto engine that meant having a high COMPRESSION ratio also (both were locked together), which meant too-high cylinder BMEP and engine knock. But in the Atkinson, Toyota leaves the intake valve open for part of the upstroke, so the total charge at the time of ignition is reduced. This means less power but, again, more efficiency. My 2010 RX450h engine has 240HP versus about 270 for its Otto-cycle cousin, but in the hybrid we also have electric motors to assist, so in fact the hybrid car has more total HP than the cousin. Very clever.
So don't look at the expansion ratio to see if premium fuel is needed. It's not. The engine is a whole different animal. And, as already mentioned, every modern engine uses a knock sensor that will kick in if necessary.
Car manufacturers use the "premium fuel" tag to maximize the specs and EPA ratings. As long as you use high-quality regular fuel, the engine will be perfectly happy but you'll lose a few HP and a fraction of an mpg.
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gadgetman1 (02-22-19)
02-23-19, 07:48 AM
#44
Shadowmite above had mentioned that I had made a comment on compression ratios in another thread. For what it's worth, here's what I wrote over there in response to a commenter's statement that premium fuel was needed due to a very high compression ratio:
-----------------------------
There's a bit more to the story these days, which is why your reasonable compression ratio rules-of-thumb probably don't apply.
Toyota hybrids use an Atkinson-style engine design, not the traditional Otto-cycle. They do so in order to gain an additional 5% or so improvement in efficiency. Efficiency comes from having a very high EXPANSION ratio, such that the engine gets as much energy out of the expanding charge as possible before opening the exhaust valve. In a traditional Otto engine that meant having a high COMPRESSION ratio also (both were locked together), which meant too-high cylinder BMEP and engine knock. But in the Atkinson, Toyota leaves the intake valve open for part of the upstroke, so the total charge at the time of ignition is reduced. This means less power but, again, more efficiency. My 2010 RX450h engine has 240HP versus about 270 for its Otto-cycle cousin, but in the hybrid we also have electric motors to assist, so in fact the hybrid car has more total HP than the cousin. Very clever.
So don't look at the expansion ratio to see if premium fuel is needed. It's not. The engine is a whole different animal. And, as already mentioned, every modern engine uses a knock sensor that will kick in if necessary.
Car manufacturers use the "premium fuel" tag to maximize the specs and EPA ratings. As long as you use high-quality regular fuel, the engine will be perfectly happy but you'll lose a few HP and a fraction of an mpg.
-----------------------------
There's a bit more to the story these days, which is why your reasonable compression ratio rules-of-thumb probably don't apply.
Toyota hybrids use an Atkinson-style engine design, not the traditional Otto-cycle. They do so in order to gain an additional 5% or so improvement in efficiency. Efficiency comes from having a very high EXPANSION ratio, such that the engine gets as much energy out of the expanding charge as possible before opening the exhaust valve. In a traditional Otto engine that meant having a high COMPRESSION ratio also (both were locked together), which meant too-high cylinder BMEP and engine knock. But in the Atkinson, Toyota leaves the intake valve open for part of the upstroke, so the total charge at the time of ignition is reduced. This means less power but, again, more efficiency. My 2010 RX450h engine has 240HP versus about 270 for its Otto-cycle cousin, but in the hybrid we also have electric motors to assist, so in fact the hybrid car has more total HP than the cousin. Very clever.
So don't look at the expansion ratio to see if premium fuel is needed. It's not. The engine is a whole different animal. And, as already mentioned, every modern engine uses a knock sensor that will kick in if necessary.
Car manufacturers use the "premium fuel" tag to maximize the specs and EPA ratings. As long as you use high-quality regular fuel, the engine will be perfectly happy but you'll lose a few HP and a fraction of an mpg.
You must only use unleaded gasoline.
Select premium unleaded gasoline with an octane rating of 91 (Research
Octane Number 96) or higher required for optimum engine performance.
If 91 octane cannot be obtained, you may use unleaded gasoline with an
octane rating as low as 87 (Research Octane Number 91). Use of unleaded
gasoline with an octane rating lower than 91 may result in engine knocking
and significantly reduced performance. Persistent knocking can lead to
engine damage and should be corrected by refueling with higher octane
unleaded gasoline.
Select premium unleaded gasoline with an octane rating of 91 (Research
Octane Number 96) or higher required for optimum engine performance.
If 91 octane cannot be obtained, you may use unleaded gasoline with an
octane rating as low as 87 (Research Octane Number 91). Use of unleaded
gasoline with an octane rating lower than 91 may result in engine knocking
and significantly reduced performance. Persistent knocking can lead to
engine damage and should be corrected by refueling with higher octane
unleaded gasoline.
I guess part of my feelings on the topic are driven by that unknown, and I'd rather not risk it. But I've no real idea what the risk actually is.
02-23-19, 08:25 AM
#45
Don't disagree at all, but there is one question that's always bothered me and I've never been able to find any conclusive data on it. This is exactly what my owners manual says:
So there's a bunch of intentionally vague "mays" and "cans" in that disclaimer. But I've always wondered - what's the long-term impact (if any?) on operating an engine in a persistent "anti-knock" condition using lower than 91? Here Lexus is clearly leaving that door open with their "persistent knocking" warning. I've never been able to find data that says it will.
I guess part of my feelings on the topic are driven by that unknown, and I'd rather not risk it. But I've no real idea what the risk actually is.
So there's a bunch of intentionally vague "mays" and "cans" in that disclaimer. But I've always wondered - what's the long-term impact (if any?) on operating an engine in a persistent "anti-knock" condition using lower than 91? Here Lexus is clearly leaving that door open with their "persistent knocking" warning. I've never been able to find data that says it will.
I guess part of my feelings on the topic are driven by that unknown, and I'd rather not risk it. But I've no real idea what the risk actually is.
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Geekteach (12-18-19)