Eddo

I own a 2008 RX350. My owners manual, Page 439, states: "If premium gasoline is not available" "If 91 octane gasoline cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91)".

It is my understanding that most new engines have a built in sensor that adjusts the engine timing to accomodate various gasoline octane ratings to prevent engine knock or ping.

lexus114

Thats true,but I am looking forward to see what Lexus responds to re:the last post.Why does the Toyota (same engine)require 87,and Lexus 91? I have my own theory on this,but would like to hear it from Lexus.

AV8R_BOB

Below are the final communications from and with Lexus. I've not received a reply to my last one so I guess their official position is to not give a straight answer...

---------------------------------------------------------
From: Bob
Sent: Friday, October 03, 2008 9:41 PM
To: 'Lexus Customer Satisfaction'
Subject: RE: Contact Lexus Email: [Reference: 080913-000069] [Incident: 080927-000089]

We’re just going around in circles here because you’re dancing around the issue and won’t give a straight answer.

Again, for about the 5th time, by your own admission the Toyota Highlander engine is identical to the Lexus engine. The Toyota engine was also tested per EPA guidelines, and Toyota says it makes 270 HP on 87 octane gas. That’s the SAME POWER as the Lexus, which you are claiming requires 91 octane for “optimal performance”.

Sorry, but that explanation does not hold water. Perhaps a lot of your customers buy it, but I’m a Masters degreed engineer who works with aircraft engines and your explanation simply does not hold water. Either deliberately or through ignorance you are not providing an accurate answer to my question. That’s why I think this is all about creating an image, a marketing gimmick.

And, no, the issue is not unavailability of premium. The issue is, if my engine will get the same performance (270 horsepower) with both premium and regular then why should I waste my money buying premium, which costs 30 cents a gallon more? In addition, only 5% of gasoline sold is premium, so it is usually not nearly as fresh as regular, ie. the gas stations’ turnover rate on premium is a lot slower than regular.


Bob

-------------------------------------------------------------------
From: Lexus Customer Satisfaction [mailto:Customer_Satisfaction_Inquiries@lexus.com]
Sent: Friday, October 03, 2008 6:51 PM
To: bob
Subject: Contact Lexus Email: [Reference: 080913-000069] [Incident: 080927-000089]

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

Thank you for allowing us to be of service to you.
Subject
Contact Lexus Email: [Reference: 080913-000069]

Discussion Thread
Response (Stefanie Oda) 10/03/2008 04:50 PM

Dear Mr. xxx:

Thank you for contacting Lexus Customer Satisfaction and for your response.

There is not intent to create an illusion by any means. We are sorry to hear you feel this way. Lexus is a luxury brand and emphasizes performance. The Lexus vehicles have been tested with premium gasoline per the EPA guidelines. Per our owner's manual, Premium unleaded gasoline with an octane rating of 91 or higher is required for optimal engine performance. However, if such premium type cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87.

If you require further assistance, please respond to this e-mail, or 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,

Stefanie N. Oda
Lexus Customer Satisfaction
Customer (Robert ) 09/30/2008 04:01 PM

I did ask the dealer, they told me to ask you. They said they have asked Lexus the same questions but they don’t get a straight answer either. They think my suspicion is probably right that specifying premium in the Lexus is just a marketing tactic to give gullible customers the illusion that their engine is "higher performance" than the identical Toyota engine for which regular gas is specified.

Is that what this is about?

Bob

------------------------------------------------------------

From: Lexus Customer Satisfaction [mailto:Customer_Satisfaction_Inquiries@lexus.com]
SENT: Tuesday, September 30, 2008 4:53 PM
TO: bob
SUBJECT: Contact Lexus Email: [Reference: 080913-000069] [Incident: 080927-000089]



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

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


SUBJECT
Contact Lexus Email: [Reference:
080913-000069]

DISCUSSION THREAD
RESPONSE (STEFANIE ODA) 09/30/2008 02:53 PM

Dear Mr. xxx:

Thank you for contacting Lexus Customer Satisfaction and for your response.

Although we understand your gasoline concerns, the many components of the Lexus vehicle in comparison with the Toyota vehicle are different
and technical in nature. We are not a technical diagnostic center and recommend to best address your concerns, please contact your Lexus dealership. We do apologize for any inconvenience this may cause you.

If you require further assistance, please respond to this e-mail, or 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,

Stefanie N. Oda
Lexus Customer Satisfaction
CUSTOMER (ROBERT ) 09/27/2008 08:43 AM
Incident created due to reply to expired incident 080913-000069.


Please give details, what do you mean by "other components and factors that are different"?

The bottom line is I’m having trouble understanding why the Lexus needs premium for optimum engine performance, when the Highlander uses the same engine and produces the same 270 HP using 87 octane regular gas. I’m looking for a straight answer to explain that.

Thanks.


Bob

-------------------------------------------------------------
From: Lexus Customer Satisfaction [mailto:Customer_Satisfaction_Inquiries@lexus.com]
SENT: Wednesday, September 24, 2008 10:19 AM
TO: bob
SUBJECT: Contact Lexus Email: [Reference: 080913-000069]



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

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

SUBJECT
Fuel spec

DISCUSSION THREAD
RESPONSE (NANETTE TRAN) 09/24/2008 08:19 AM

Dear Mr. xxx:

The design objectives of the two vehicles are different. Even though the engines of the RX 350 and Highlander are the same, there are other components and factors that are different. Lexus recommends you to use premium unleaded gasoline with an octane rating of 91 or higher for optimum engine performance, however if that is not available, you may use unleaded gasoline with an octane rating as low as 87. If you have further concerns, please refer to your Owner's Manual.

If you require further assistance, please respond to this e-mail, or 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,

Nanette Tran
Lexus Customer Satisfaction
CUSTOMER (ROBERT ) 09/23/2008 07:17 PM


Thank you for confirming that [both Toyota Highlander and Lexus RX350 use the identical engine].

Now, back to my original question regarding the fuel specification. Here’s what I said:

I just bought my bride a new 2009 RX-350 for her 25th anniversary. Looking through the book I see 91 OCTANE PREMIUM gas is required.

According to published data, it appears the Toyota Highlander and RX-350 use the identical 3.5L V6 [which you have just confirmed]. However, Toyota recommends 87 OCTANE REGULAR gas in the Highlander.

Can you please provide an explanation as to why the Lexus needs Premium but the same engine in a Toyota Highlander only requires Regular?

Is it Ok to use Regular gas in the RX-350?

If so, are there any negative consequences?

If there are some negative consequences, why don’t they occur in the Highlander as well?

Can you please address those questions.

Thanks.

Bob

---------------------------------------------------------
From: Lexus Customer Satisfaction [mailto:Customer_Satisfaction_Inquiries@lexus.com]
SENT: Tuesday, September 23, 2008 4:42 PM
TO: bob
SUBJECT: Contact Lexus Email: [Reference: 080913-000069]



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

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


SUBJECT
Fuel spec

DISCUSSION THREAD
RESPONSE (NANETTE TRAN) 09/23/2008 02:42 PM

Dear Mr. xxx:

Thank you again for contacting Lexus Customer Satisfaction. I sincerely apologize about the delay.

You are correct in stating that engine specifications are identical for the RX 350 and Highlander and are thus correct when stating both vehicles use the same engine.

If you require further assistance, please respond to this e-mail, or 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,

Nanette Tran
Lexus Customer Satisfaction
CUSTOMER (ROBERT ) 09/15/2008 10:51 AM
-----------------------------------------------------------

What is the compression ratio of the RX-350 and the Highlander?

Per the letter I sent you, published data shows both the Highlander and the RX-350 have a compression ratio of 10.8. All of the engine specs are identical, so it appears it is the same engine used in both vehicles.

Bob
-------------------------------------------------------

From: Lexus Customer Satisfaction [mailto:Customer_Satisfaction_Inquiries@lexus.com]
SENT: Monday, September 15, 2008 11:55 AM
TO: bob
SUBJECT: Contact Lexus Email: [Reference: 080913-000069]



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

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


SUBJECT
Fuel spec


RESPONSE (NANETTE TRAN) 09/15/2008 09:54 AM
Dear Mr. xxx:

Thank you for contacting Lexus Customer Satisfaction. Your concern is important to Lexus, and we appreciate the time you have taken to share your thoughts. We are dedicated to providing superior service. In circumstances that require our attention, we will assist in the resolution process.

Per your inquiry, the Lexus RX 350 has a higher compression motor than the Toyota Highlander, which requires premium gasoline for optimum engine performance. If Premium gasoline is not available, you may use unleaded gasoline with an Octane Rating as low as 87. The use of such gasoline will not allow your vehicle to operate at optimum engine performance and may also cause persistent heavy knocking. For more information, please refer to your Owner's Manual or your local Lexus dealership.

If you require further assistance, please respond to this e-mail, or 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,

Nanette Tran
Lexus Customer Satisfaction
CUSTOMER (ROBERT ) 09/13/2008 07:56 AM
-----------------------------------------------------
See letter attached.

Note the model list in your email form does
not include the RX-350

AM1

iTrader: (6)

im not trying to instigate or knock what anyone does with his or her car, but seems odd that they dont have a straight answer. this is also more or less the same answer when i asked the dealer this same question?

lexus114

I think the only difference is in the ecm. It`s peaked up for more performance.And is programed/mapped for 91 octane.

AV8R_BOB

Again, if you read the posts, the performance specs are identical for both engines. The Lexus does NOT get "more performance".

jfelbab

2009 Highlander AWD Limited (3748 lbs curb weight) did 0-60 mph 8.1 sec.

2009 RX350 AWD (4,090 lbs curb weight) did 0-60 mph in 7.3 sec.

Source: http://consumerguideauto.howstuffworks.com

It is clear that there is a difference. I'd call the difference in performance obvious, Bob.

lexus114

Yeah,..........what he said.

lexus114

AV8R I`m just goofing around.My opinion is to try this,use 87 for two tank fulls,record mpg.Then,use at least two tanks of premium and do the same.If little or no difference in mpg or performance,you have your answer... Now,if you do notice a difference in performance or especially with mpg using premium,you definitely have your answer.That is exactly what I did with my 01 RX,and I have noticed a difference more in performance vrs. mpg. Plus my converters/exhaust smelled rotten going up hills on 87 fuel.And,my trans. shifts smoother on premium.

AM1

iTrader: (6)

im not even sure how to answer this without getting it deleted. bob has tried to get some real evidence from the "horse's mouth" so to speak from lexus HQ, and yet you guys still need to find outside reasons to refute it? okkkkkkkkkkkk

harleydjce

Same base engine. Same horsepower. Slightly higher Torque in the Lexus RX350

AV8R_BOB

As an engineer I don't accept subjective comparisons, or objective comparisons that are not well measured.

Things like "smells", and "noticing a performance difference", and even most mpg checks are not valid.

Mpg checks must be over the same route under the same conditions in order to be valid. Especially when the mpg differences are small. Also both reg and premium must have either ethonol or no ethonol. That's hard to find around here since reg has it and premium doesn't. Pure gas with no ethonol will get higher mpg due to more BTU's per gallon.

Performance should be measured on a dyno. Too many variables with a timed 0-60 run for example. Humans driving the car, working the stopwatch, etc.

AV8R_BOB

Why use Consumer Guide data? Here's the manufacturer data:

Toyota Highlander AWD Limited is 4321 lbs
http://www.toyota.com/highlander/specs.html

Lexus RX350 AWD is 4090 lbs
http://www.lexus.com/models/RX/detai...fications.html

Given that by Lexus' admission both vehicles have identical engines, it is not unexpected that the lighter vehicle would accelerate faster. That's due to a higher power to weight ratio, not premium gas.

Also when comparing acceleration you need to consider the transmissions (gear ratios, shifting points, etc) . I don't know if both vehicles have the same transmission or not.

AV8R_BOB

Thank you.

I think there is psychology at play... some folks in love with their vehicle and can't stand anything perceived as criticism.

The G Man

Just because its the same engine, that doesnt mean everything else is the same. There is a lot of other components and electronics that might differ between the 2 powertrain. The bottom line is, we know the RX can take advantage of the higher octane and the verdict is still out as far as if Toyota can.