What fuel grade are you using in your RX350?
07-17-20, 07:09 AM
#211
If you choose to use 87 only use top tier gas like Shell, BP, etc and add a fuel cleaner every oil change like Techron. Your engine will appreciate the kind gesture.
As a preference I like the way the car performs with higher grade gas to me its worth the few cents more in my area. We can debate this for weeks on whats recommended vs on really whats better for your $50k+ vehicle so I use nothing less than 89.
Just my 2cents...
As a preference I like the way the car performs with higher grade gas to me its worth the few cents more in my area. We can debate this for weeks on whats recommended vs on really whats better for your $50k+ vehicle so I use nothing less than 89.
Just my 2cents...
07-17-20, 07:55 AM
#212
Correct me if I'm wrong but isn't the RX's 3.5-litre V6 engine normally aspirated that doesn't really need premium fuel? Every other non-turbo V6 engine in the market uses similar wordings regarding use of fuel (87 or higher) as I have a Honda Pilot V6. Premium fuel is required for engines with high compression ratios and are specifically mentioned in their User Manuals.
I believe using top-tier brands is best and a dash of fuel cleaning additives at any interval you decide. I only use Shell and if not available I go for other top-tiers.
Lexus RX350 UM statement:
You must only use unleaded gasoline. Select octane rating 87 (Research Octane Number 91) or higher. Use of unleaded gasoline with an octane rating lower than 87 may result in engine knocking. Persistent knocking can lead to engine damage. At minimum, the gasoline you use should meet the specifications of ASTM D4814 in the U.S.A.
Honda Pilot UM statement:
Fuel Recommendation - Your vehicle is designed to operate on unleaded gasoline with a pump octane number of 87 or higher. Use of a lower octane gasoline can cause a persistent, heavy, metallic rapping noise that can lead to engine damage.
I believe using top-tier brands is best and a dash of fuel cleaning additives at any interval you decide. I only use Shell and if not available I go for other top-tiers.
Lexus RX350 UM statement:
You must only use unleaded gasoline. Select octane rating 87 (Research Octane Number 91) or higher. Use of unleaded gasoline with an octane rating lower than 87 may result in engine knocking. Persistent knocking can lead to engine damage. At minimum, the gasoline you use should meet the specifications of ASTM D4814 in the U.S.A.
Honda Pilot UM statement:
Fuel Recommendation - Your vehicle is designed to operate on unleaded gasoline with a pump octane number of 87 or higher. Use of a lower octane gasoline can cause a persistent, heavy, metallic rapping noise that can lead to engine damage.
07-17-20, 08:08 AM
#213
I use 87 octane in my 2020 Rx 350 per the Owner's Manual.
My 2008 Rx 400h Hybrid recommended but didn't require Premium fuel in the Owner's Manual. After a lengthy discussion with my Lexus mechanic, I decided to use 87 octane fuel in that vehicle also. After 12 years and 150,000 miles, the car still ran perfect with no fuel related problems.
I elected not to buy a 202 Rx 450h Hybrid because it now requires premium fuel which completely negates the savings from the better mileage of the hybrid vehicle.
My 2008 Rx 400h Hybrid recommended but didn't require Premium fuel in the Owner's Manual. After a lengthy discussion with my Lexus mechanic, I decided to use 87 octane fuel in that vehicle also. After 12 years and 150,000 miles, the car still ran perfect with no fuel related problems.
I elected not to buy a 202 Rx 450h Hybrid because it now requires premium fuel which completely negates the savings from the better mileage of the hybrid vehicle.
07-17-20, 09:50 AM
#214
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Cocal (07-17-20)
07-17-20, 09:53 AM
#215
Depends on the car. I had an 2008 Acura TL and it had a v6 non-turbo it needed 91-93.
If you did use 87 you had add an fuel additive.
If you did use 87 you had add an fuel additive.
07-17-20, 05:48 PM
#216
Actually, if you compare your gas mileage obtained from a full tank of 87 octane, (using the odometer and a calculator, not the figure on the instrument panel), to a full tank of 91 or 93 octane, under the same driving conditions, you can get beyond perception and have data.
I spent years throwing out extra cash for premium gas. It was only 20 cents/gal more at the time, but I can relate to the disease.
07-17-20, 10:46 PM
#217
My Chevron gas station has a different layout for gas buttons than my 76 gas station so I got mixed up.
07-18-20, 02:30 PM
#218
Before buying the 2020 RXH 450, I had done some calculations and did find that even if one used the "required" Premium fuel in the Hybrid gas price wise one is still better off. I bought the Hybrid for the better power over the 350 Rx and I am happy I did. My wife's 2017 Rx 350 gives a mileage of 19 overall. My average on the 2020 Rxh 450 is a minimum of 26. This works out to around 36.4% better fuel efficiency over the 350. Today's gas price at my local Costco is 1.82 for regular and 2.18 for premium. The premium gas thus costs 19.8% more than the regular. So I am in the money. Thus if anyone is not buying a hybrid because of fuel gas being more expensive, this should not be a reason to not buy the hybrid. No doubt if you consider the extra cost for a Hybrid over a non Hybrid, then one will need to work out the payback period. I did not do that, because my intent was less engine noise and better power. If I did that type of analysis, I probably would have enough considered a Prius. However, after experiencing the very low sound when driving on the battery power, my next car is going to be an electric. If Lexus has this in 5 years that would be great, otherwise, I will need to consider other brands. Telsa's reliability is still poor and build quality too.
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mckdaddy (07-18-20)
07-19-20, 07:10 AM
#219
Lexus Test Driver
Thread Starter
Before buying the 2020 RXH 450, I had done some calculations and did find that even if one used the "required" Premium fuel in the Hybrid gas price wise one is still better off. I bought the Hybrid for the better power over the 350 Rx and I am happy I did. My wife's 2017 Rx 350 gives a mileage of 19 overall. My average on the 2020 Rxh 450 is a minimum of 26. This works out to around 36.4% better fuel efficiency over the 350. Today's gas price at my local Costco is 1.82 for regular and 2.18 for premium. The premium gas thus costs 19.8% more than the regular. So I am in the money. Thus if anyone is not buying a hybrid because of fuel gas being more expensive, this should not be a reason to not buy the hybrid. No doubt if you consider the extra cost for a Hybrid over a non Hybrid, then one will need to work out the payback period. I did not do that, because my intent was less engine noise and better power. If I did that type of analysis, I probably would have enough considered a Prius. However, after experiencing the very low sound when driving on the battery power, my next car is going to be an electric. If Lexus has this in 5 years that would be great, otherwise, I will need to consider other brands. Telsa's reliability is still poor and build quality too.
07-19-20, 07:48 AM
#220
Before buying the 2020 RXH 450, I had done some calculations and did find that even if one used the "required" Premium fuel in the Hybrid gas price wise one is still better off. I bought the Hybrid for the better power over the 350 Rx and I am happy I did. My wife's 2017 Rx 350 gives a mileage of 19 overall. My average on the 2020 Rxh 450 is a minimum of 26. This works out to around 36.4% better fuel efficiency over the 350. Today's gas price at my local Costco is 1.82 for regular and 2.18 for premium. The premium gas thus costs 19.8% more than the regular. So I am in the money. Thus if anyone is not buying a hybrid because of fuel gas being more expensive, this should not be a reason to not buy the hybrid. No doubt if you consider the extra cost for a Hybrid over a non Hybrid, then one will need to work out the payback period. I did not do that, because my intent was less engine noise and better power. If I did that type of analysis, I probably would have enough considered a Prius. However, after experiencing the very low sound when driving on the battery power, my next car is going to be an electric. If Lexus has this in 5 years that would be great, otherwise, I will need to consider other brands. Telsa's reliability is still poor and build quality too.
I miss the power and instant torque of my last Lexus Rx400h hybrid but the math doesn't work for me if I have to pay 34% more for fuel for the next 10 years even when the hybrid is now only $1000 more up front. The other complaint I had with the hybrid in a northern climate was that my mileage dropped dramatically in the winter. Basically, the engine can't run on battery power with the heater on which is about 4 months or more in Wisconsin. I also found that the mileage on the hybrid dropped each year that I owned the car. I suspect this was from aging of the batteries. I averaged 28 mpg in the first year and about 23 mpg by 8-10 years.
Last edited by jrobe; 07-19-20 at 07:54 AM.
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bamalam (07-19-20)
07-20-20, 03:37 AM
#221
Pole Position
Today in my WI town, premium fuel is 34% higher than 87 octane fuel (70 cents per gallon more). This is very similar to when I bought my Rx350 last fall.
I miss the power and instant torque of my last Lexus Rx400h hybrid but the math doesn't work for me if I have to pay 34% more for fuel for the next 10 years even when the hybrid is now only $1000 more up front. The other complaint I had with the hybrid in a northern climate was that my mileage dropped dramatically in the winter. Basically, the engine can't run on battery power with the heater on which is about 4 months or more in Wisconsin. I also found that the mileage on the hybrid dropped each year that I owned the car. I suspect this was from aging of the batteries. I averaged 28 mpg in the first year and about 23 mpg by 8-10 years.
I miss the power and instant torque of my last Lexus Rx400h hybrid but the math doesn't work for me if I have to pay 34% more for fuel for the next 10 years even when the hybrid is now only $1000 more up front. The other complaint I had with the hybrid in a northern climate was that my mileage dropped dramatically in the winter. Basically, the engine can't run on battery power with the heater on which is about 4 months or more in Wisconsin. I also found that the mileage on the hybrid dropped each year that I owned the car. I suspect this was from aging of the batteries. I averaged 28 mpg in the first year and about 23 mpg by 8-10 years.
Last edited by Freds430; 07-20-20 at 03:44 AM.
07-20-20, 03:58 AM
#222
LOL. What a waste. I do what the owner manual says and I’ve never been steered wrong. I trust trained engineers from the factory far more than any advice one will receive from a message board! Go figure. I put the required 87 in this glorified station wagon and save the 93 oct for something that can use it, like my Mustang!
07-21-20, 08:10 PM
#223
See: Owners Manual Page 454 8.1 Specifications 2020 RX350
Octane rating 87 (research octane 91 or higher). 87 Octane is R+M/2 They want 91 or higher on the Research (RON) side. The motor method (MON) is more stressed way of rating octane. My Dad ran oil refineries his whole career and I spent one whole summer rating gasoline's for octane.
A good reference is the Colonial Pipeline specification for Reformulated Regular Gasoline Blendstock (intended to blended with 10% denatured fuel (ethanol):
"Minimum Colonial Pipeline Company CPC Product Specifications March 2016 1 of 1 PRODUCT SPECIFICATIONS 3.5.1 REFORMULATED REGULAR GASOLINE BLENDSTOCK (RBOB) FOR BLENDING WITH 10% DENATURED FUEL ETHANOL Cancels Previous Issues of F grades (92% PURITY) AS DEFINED IN ASTM D4806 This RBOB may not be combined with any other RBOB except RBOB having the same requirement for oxygenate type and amount. All parameters must be met after blending with denatured fuel ethanol unless noted. ALL F GRADE REQUIREMENTS (SEGREGATED AND FUNGIBLE)
RON ASTM D2699 Test Report No number cited
MON ASTM D2700 Test Test results minimum 82.0
(R+M)/2 Test Test results minimum 87.0
Benzene (vol%) ASTM D3606 1.30
Oxygen Content, weight % ASTM D5599 (See Note) 1,2,7,8
Aromatics (vol%) ASTM D5769 (See Note) Maximum 50 (See Note) 2
E200 (vol%) ASTM D86 Min 30 Max 70
E300 (vol%) ASTM D86 70 100
Olefins (vol%) ASTM D1319 [C],D6550 Max 25
Sulfur (ppmwt) ASTM D2622 Max 80 9
Non-VOC Controlled Requirements
RVP (psi) ASTM D5191 3 Grades F3,3F (Non-VOC Controlled) Max 11.5; F4,4F (Non-VOC Controlled) Max 13.5; F5,5F (Non-VOC Controlled) Max 15.0 VOC Controlled Requirements (Grades F1,F2,1F,2F, only)
Some content admitted Retrieved from https://das.nh.gov/purchasing/Docs/Bids/Attachments/RFB%202007-18%20Gasoline%20Specifications.pdf July 21, 2020
Specs are what is required to move product on the Colonial pipeline. Other pipelines checked are similar (Buckeye, Laurel, Norco, Wood River)
Lexus specs are crystal clear: 87 Octane (R+M is implied) with a minimum research octane (RON) of 91. That being the case: 91 + MON = 174/2 = 87(R+M/2) Motor Octane number( MON) must be a minimum of 83. Pipeline specs say 82 but R+M/2 must be 87.
Simply put: Run what you want--it is a matter solely of preference. My LS400/430s and SC00s and SC430 always ran better and got better mileage on 89 (mid grade in the South). Grade price differentials are now more than 10% of the previous grade costs around where I live. So, if I am not getting at least at 10% increase in mileage 2-2.5 MPG it is not good economics. All the major grades have the additive packages to keep your car running clean. (Excuse underline. I tried to get rid of it.)
Octane rating 87 (research octane 91 or higher). 87 Octane is R+M/2 They want 91 or higher on the Research (RON) side. The motor method (MON) is more stressed way of rating octane. My Dad ran oil refineries his whole career and I spent one whole summer rating gasoline's for octane.
A good reference is the Colonial Pipeline specification for Reformulated Regular Gasoline Blendstock (intended to blended with 10% denatured fuel (ethanol):
"Minimum Colonial Pipeline Company CPC Product Specifications March 2016 1 of 1 PRODUCT SPECIFICATIONS 3.5.1 REFORMULATED REGULAR GASOLINE BLENDSTOCK (RBOB) FOR BLENDING WITH 10% DENATURED FUEL ETHANOL Cancels Previous Issues of F grades (92% PURITY) AS DEFINED IN ASTM D4806 This RBOB may not be combined with any other RBOB except RBOB having the same requirement for oxygenate type and amount. All parameters must be met after blending with denatured fuel ethanol unless noted. ALL F GRADE REQUIREMENTS (SEGREGATED AND FUNGIBLE)
RON ASTM D2699 Test Report No number cited
MON ASTM D2700 Test Test results minimum 82.0
(R+M)/2 Test Test results minimum 87.0
Benzene (vol%) ASTM D3606 1.30
Oxygen Content, weight % ASTM D5599 (See Note) 1,2,7,8
Aromatics (vol%) ASTM D5769 (See Note) Maximum 50 (See Note) 2
E200 (vol%) ASTM D86 Min 30 Max 70
E300 (vol%) ASTM D86 70 100
Olefins (vol%) ASTM D1319 [C],D6550 Max 25
Sulfur (ppmwt) ASTM D2622 Max 80 9
Non-VOC Controlled Requirements
RVP (psi) ASTM D5191 3 Grades F3,3F (Non-VOC Controlled) Max 11.5; F4,4F (Non-VOC Controlled) Max 13.5; F5,5F (Non-VOC Controlled) Max 15.0 VOC Controlled Requirements (Grades F1,F2,1F,2F, only)
Some content admitted Retrieved from https://das.nh.gov/purchasing/Docs/Bids/Attachments/RFB%202007-18%20Gasoline%20Specifications.pdf July 21, 2020
Specs are what is required to move product on the Colonial pipeline. Other pipelines checked are similar (Buckeye, Laurel, Norco, Wood River)
Lexus specs are crystal clear: 87 Octane (R+M is implied) with a minimum research octane (RON) of 91. That being the case: 91 + MON = 174/2 = 87(R+M/2) Motor Octane number( MON) must be a minimum of 83. Pipeline specs say 82 but R+M/2 must be 87.
Simply put: Run what you want--it is a matter solely of preference. My LS400/430s and SC00s and SC430 always ran better and got better mileage on 89 (mid grade in the South). Grade price differentials are now more than 10% of the previous grade costs around where I live. So, if I am not getting at least at 10% increase in mileage 2-2.5 MPG it is not good economics. All the major grades have the additive packages to keep your car running clean. (Excuse underline. I tried to get rid of it.)
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07-22-20, 08:50 AM
#224
Very well explained. I've asked the Lexus tech during service before. He said that the on-board computer default tune is set for 87 grade fuel. One reason for that is at least 87 grade is available in every gas station in the US. It actually does more harm switching back & forth grades if done often. He also said if I prefer 89 just stick to it the computer will adjust, and 93 is a waste of money for the RX350. Pretty logical explanation, but enjoyed CMMetcalf fuel lesson.
07-22-20, 09:42 PM
#225
tbh it doesnt really "matter" at least in the rx, most of the gas stations in america you already fill up at cheat the system.. The're private owners that pinch pennies like many businesses already do. Plenty of stories of someone filling up gas with a semi delivering some gas and the manager yelling to the driver if there's extra unleaded throw it in the premium tank. The trucker 9 times out of 10 agrees as if not he'll have to drive back and unload the gas which is a big hassle and paper work for everyone. But all gas in america at least is made from one manufacture that has pretty strict and stringent rules and requirements relating to octane levels, then bought by sibling companies which take it and add their own "secrete sauce" as in additives/detergents like shell, valero, cheveron, etc. The issue lies in private owners which all gas stations are, not being truthful and adding lower octane fuel in higher octane tanks.
But all modern gas made now days will run fine in any modern car unless its a "performance" car that needs later ignition as higher octane gas is less flammable. If your gas has ethanol in it, its already watered down so octane numbers do hold value for how the car runs. But in the rx I've filled from 85 to 91 with no difference lol
But all modern gas made now days will run fine in any modern car unless its a "performance" car that needs later ignition as higher octane gas is less flammable. If your gas has ethanol in it, its already watered down so octane numbers do hold value for how the car runs. But in the rx I've filled from 85 to 91 with no difference lol