lexus114

Recently you submitted a question to the Lexus Customer Satisfaction Department.

Thank you for allowing us to be of service to you.


Subject
OCTANE FUEL

Discussion Thread
Response (Jaret Minami) 07/29/2008 09:10 AM
Dear Mr. McArdle:

Thank you for contacting Lexus Customer Satisfaction regarding the recommended gasoline for your Lexus RX. We appreciate the time you have taken to share this communication with us.

Lexus recommends using select premium-unleaded gasoline with an Octane Rating of 91 or higher for optimum engine performance. However, if such premium type cannot be obtained, you may temporarily use unleaded gasoline with an Octane Rating as low as 87. Your vehicle will operate on an octane rating of 87, but might experience lower performance and engine knocking. You may also refer to the last page of your owner’s manual for more information regarding the recommended type of gasoline.

If you require further assistance, please contact Lexus Customer Satisfaction at 1-800-255-3987, Monday through Friday, 5:00 a.m. to 6:00 p.m., or Saturday, 7:00 a.m. to 4:00 p.m., Pacific Time.

Sincerely,

Jaret Minami
Lexus Customer Satisfaction
Customer (Ryan R. McArdle) 07/29/2008 08:01 AM
My RX manual states select 87 octane fuel,for improved vehicle performance,select 91 octane or higher.My question is;what is the ecm calibrated for? Can I safely use 87 octane fuel? I can not seem to get a straight answer re;this subject.Any help from you will be greatly appreciated.
Sincerely,
Ryan R. McArdle

**Just thought some of you may get a little kick out of this.**

code58

Ryan- My DIL has used 87 in her 99RX and now has over 120k mi. and I do the work on it for her and I can tell you it runs just fine on 87. Would it run stronger on 91? Could be but when it runs as good as it does on 87 she has chosen to run that and I probably would too.

bob2200

That's interesting. I went by the owner's manual and have used only 87 octane (regular) unleaded for the past 6 years (since new) in my 2002 RX300. It runs fine as far as I can tell.

The owner's manual in my mother's 2002 ES300 recommends premium (91 octane) and she has been running 89 octane mostly with no perceived ill-effects. She doesn't do any high speed/highway driving, so I was less worried about her using a lower than recommended octane. Earlier year ES300s recommended 87 octane.

Since this was a transition period for Lexus, in switching from 87 octane to 91 octane, I'm inclined to think that the guy who wrote the letter at Lexus was in error. That's my view.

lexus114

Truely,I don`t want to keep beating a dead horse,but I was curious as to what Lexus would have to say re;octane.Remember,the first few word`s say(select 87 octane) I just thought you guy`s would like to see their response.

19psi

the only thing they don't mention, which is most important in my opinion, is that the reduced performance will ONLY be noticed under full throttle, shifting at or near redline conditions. there will be no difference in performance during "grandma" driving or cruising situations between 87 or 91+ octane fuels.

lexus114

Personally I agree with you,my only concern with 87 is these 1MZFE motor`s are a 10.5:1 compression engine.That is considered a high compression engine,especially for a street motor.Basically all that should happen is it won`t perform to it`s full ability on lower octane.But here again,let`s not start this again,or we will be getting some hate mail..: D

19psi

yeah, this is a horse that's been beaten for way too long. i just hope everyone does a little reading on the subject so we dont have to keep explaining it. sometimes i think lexus and other brands would give it's customers a little credit and explain it a little further as to why 87 or 91+ must be used. i'm sure most people would understand.

rx300mm

Lexus114, Thanks for posting the letter, interesting.
True comment about " but might experience lower performance.." I sometimes fill the tank with 91 octane and I notice the performance/power is better in my 2001 RX but I don't need that level of power so I use 87 most of the time and never experienced engine knocking. I use 87 90% of the time.

lexus114

Thank you for your input regarding this RX300mm, I appreciate any comments on this subject.

My0gr81

My 2006 RX330 manual clearly states that 91 (RON) octane fuel is recommended.

To answer the old compression ratio argument. Although most modern engine have higher compression ratios, they rarely operate at that ratio other than at WOT or if boosted

source for the quotes: wikipedia and various other sources specializing in gasoline including: http://www.faqs.org/faqs/autos/gasoline-faq/part1/

habeeb89

iTrader: (3)

I would honestly stick with the 91 octane, they price difference is not as much as you might think.

lexus114

It`s around a 20 cent. difference.I blow more than that on stupid things like coffee etc.

My0gr81

Around here, it is 11 cents a litre, that is $7 on a full tank twice a week so about $728 a year, hardly chump change.

lexus114

Whoa,I wonder why such a drastic difference up their?

lexus114

Plus with your colder climate,I would use regular anyway.