Premium for 2010-2011 RX350? (merged threads)
09-29-11, 03:11 PM
#226
09-29-11, 04:41 PM
#229
The only problem is, suppose it really does make a difference, and I buy a used 2010 and start pumping the premium gas, meanwhile the previous owner has already crapped up the engine by using the lower octane fuel, I'm kinda throwing my money away. Guess you can't really know for sure. 
09-29-11, 05:32 PM
#230
running lower octane will not crap-up the engine
computer tunes engine timing based on spark knock from whatever octane you run
running higher octane can be cheaper in the long run as you'll get better mpg from higher octane
computer tunes engine timing based on spark knock from whatever octane you run
running higher octane can be cheaper in the long run as you'll get better mpg from higher octane
09-29-11, 05:38 PM
#231
If there was no changes to the engine, I would think Lexus would have change the fuel requirement this year for the RX, the same time as the ES. I think at a minimum, the ignition timing program was change and I am not sure if there are any mechanical changes such as cam shaft angles and valve timing.
09-29-11, 10:36 PM
#232
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They really didn't change anything, they just changed the reccomended fuel type so people would stop having sticker shock at the gas pumps. This engine is designed to handle 87 octane....as is most non-high performance engines sold on the market today.
09-30-11, 05:31 AM
#233
Please cite your source, or were you just speculating?
On something like this, we need factual information, not speculation.
On something like this, we need factual information, not speculation.
09-30-11, 06:15 AM
#234
Lexus Champion
09-30-11, 08:32 AM
#235
Driver School Candidate
Philadelphia Inquirer newspaper today had an excellant artical. In summary they said if manufacturer says 91 octane "recommended" 87 octane is OK. If it says 91 octane "required" then use only high octane.
The downside to using lower octane is a very slight reduction in power only under hard acceleration or load.
The Inquirer stated most people can not tell the difference and most cars can safely use 87.
I am an engineer who worked for a refinery. Regular gas has a slightly higher BTU/gal and very slight increase in specfic gravity. It should show no decrease in milage.
The downside to using lower octane is a very slight reduction in power only under hard acceleration or load.
The Inquirer stated most people can not tell the difference and most cars can safely use 87.
I am an engineer who worked for a refinery. Regular gas has a slightly higher BTU/gal and very slight increase in specfic gravity. It should show no decrease in milage.
09-30-11, 10:27 AM
#236
use what manufacture "require"/"recommend". both 10/11 "require" to use premium as stated by Lexus. some have opt for regular without any issue(s), but for me, I lost about 2MPG and I "felt" the degrading of performance. "degrading" is probably more noticible on smaller engine like my Miata which MAZDA has Premium as "recommended" but I use premium from current and past Miatas and I can feel/hear the difference as soon as I switch.
10-02-11, 09:49 AM
#237
I have used the mid range 89 octane gas and the RX runs fine, I did not notice any difference in the power or gas mileage. It sure has more power when it is just washed and waxed though. Funny how that works!!!
Cheers,
Jim!
Cheers,
Jim!
10-02-11, 11:38 AM
#238
Lexus Champion
For the Genesis V8 Hyundai shows the hp/torque ratings using both regular and premium (385 prem./378 reg.). Makes it nice for the driver to decide which they want to use. The V6 is rated using regular only (333 hp).
10-02-11, 04:10 PM
#239
Lexus Test Driver
The only problem is, suppose it really does make a difference, and I buy a used 2010 and start pumping the premium gas, meanwhile the previous owner has already crapped up the engine by using the lower octane fuel, I'm kinda throwing my money away. Guess you can't really know for sure.
You'll be just fine.
What's more improtant is you don't stick with one oil company.
Do a switch every now and then, say every 5000 miles.
That way you will flush the additive from the previous oil Co.
These gasoline have the same base, meaning all these Co are using the same stuff.
And they're sharing. It makes more sense that way than to deliver a truck of gasoline 3000 miles.
What makes them unique/special is the additive. And that's what you should be more concerned about.
10-02-11, 05:49 PM
#240
Driver
I've used four grades in my '11 RX, 87, 89, 91 and 94 octane and honestly haven't seen any difference in mileage or performance. in fact my worst mileage was from a tank of Sunoco 94. I'm sure that using 87 octane produces somewhat less hp/torque but it doesn't show up in normal RX type driving. The 3.5L V6 is the same basic engine as in the RAV4, Camry, Avalon, Venza and others. It is just rated at higher numbers in Lexus applications by running it on premium fuel. Just because someone can afford to pay $50,000+ for a car doesn't mean they want to throw their money away giving it to the oil companies for no measurable return!