Lew270

Guys/Gals,
I have been reading much of the prior posts on the debate over the use of 87 Octane gas v.s. 93 Octane. I believe most everybody "believes" no damage will occur to the engine if 87 is used...BUT has anyone ever spoke with a Lexus Mechanic or Service manager and obtained facts? (Unfortunately) I am an engineer by education and I tend to believe facts over opinion. Most of what I have read seems to be opinion. I would love to know if anyone has any facts showing the 87 octane will not cause any damage to the engine...(I have been using 93 since day 1, but the fill ups are getting expensive these days...
PS
I can deal with a lower HP rating…I bought a luxury car not a corvette
Thanks in advance for your input

LexBob2

I haven't seen any proof on the subject. Something may be out there but I've never come across it.

To me, it seems that if someone is on the fence on the regular vs. premium question just make a judgement call and go with what you think is best.

Luxotic

iTrader: (6)

the octane will not cause damage to the engine as much as it may cause damage to other parts such fule injectors .. even then most of my family drive lexus new old big or small and everyone uses 87 octane there are a few that are pushing 200k without any major problems so far ... just the regular maintainence .... es350 is not a high performance car so 87 is ok

http://www.usatoday.com/money/autos/...emiumgas_x.htm

MadMax96

I don't think you'll get a Lexus mechanic to tell you anything besides the recommended octane should be used. It's all about covering their ****.

FWIW - I've been using 87 octane in my '07 for the past 3-4 months and the car seems the same in all aspects - performance, mileage, etc..

I seriously only think you'd see a difference in performance if you hooked it up to a dyno.

AlGator

I'd hardly regard the opinion on the subject of a Lexus Service manager or mechanic as fact. As mentioned, its unlikely either would advise something contrary the manufacturer recommendations. I consider anything dealer service departments suggest as false until proven otherwise.

As to the necessary octane consider; The same spec 3.5L engine in the Avalon takes regular fuel and is rated at 268 HP, yet in the ES 350 HP is 272 on premium. However, for the 2011 ES 350 Lexus dropped the premium fuel recommendation and advertised HP fell to 268, exactly the same as the Avalon.

My guess is the 3.5L in Lexus and Avalon are, and have been, the same engine all along but to distinguish it from lesser bretheren Lexus called for premium fuel in the ES 350 and adds 4 HP.

jagtoes

As long as the engine management system has the capability to adjust the timing there is no reason other then the HP difference in running 87 octane. I have not seen the actual data but the system has no problem retarding the timing and reading knock sensitivity allowing for lower octane fuel. I suspect that there is some data somewhere but I wound not spend the time to research it. I would be surprised if anyone can tell the difference between a tank of 87 vs. 93.

LexBob2

Good points. The Camry, Venza, RAV4, Highlander and Sienna also use the same engine rated 268-270 hp all on regular.

Milliken

It is absolutely stupid paying extra for years to come if we don't know for fact that the ES needs 91 or higher. Put it that way, did any one here heard from any body who suffered from engine problems traced back to using regular gas? In these days, I would buy several candy bars to my kids every time I save 5 bucks or so on a full tank. Would it make a relationship difference on my kids towards me if I keep doing it for 5 to 10 years? Damn sure, it would. Why do we want to please the ES engine for nothing and not to our kids?

"wasting money" feels bad, agree?
With buying a Lexus my objective is to save on the cost of ownership, every bit counts.

So, it all boils down to any reports on regular gas kills the ES engine at all??? Statistics helps.
What about plugging up them injectors I am not technical enough to go into details?

Thanks.

Lew270

Nicely put Milliken...good question...does anyone know of any engine (et al) damage due to a lesser octane usage?
My next fill up is going to be 87

kewl

Well, since some people like facts...can anyone show us where, in the 07 owners manual, it says you MUST use 91 fuel? In fact, there is that word again, you will find words to the effect that 91 is recommended, but that lower octane fuel can be used but it will result in reduced performance. The word damage is not used... What more do you need from Lexus on that point. Use 87!

Lew270

This is exactly what Lexus says, straight from my oweners manual...

Page 394, Section 6-1 Specifications.
"Your vehicle must use only unleaded gasoline.
Premium unleadedgasoline with an octane rating of 91 (Research Octane Number 96) or higher required for optimum engine performance"

Further below, Bullet point #2 it states:
"If Premium gasoline is not available"
"If 91 rating gasoline cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91)"

Lew270

Even further on page 396 under a NOTICE:

"Use of unleaded gasoline with an octane rating lower than 91 may result in engine knocking. Persistent knocking can lead to engine damage and should be corrected by refueling with higher octane unleaded gasoline"

Milliken

Yes, as Lew270 said here, I read exactly the same wording in my 2008 manual but on difference page numbers.

So, the factory "recommended" 91+ but not mandatory. If it is likely to cause engine problem with 87, they would use "DO NOT USE" instead. "Recommend" means recommend and we don't have to follow. I guess that is the best Lexus can tell us trying to build an image of an luxury car similar to paying $2+ for a Starbuck versus a $1.50 Tim Hortons - the myth that higher price is better. I personally like the Tim.

I am going to try for myself. Drive the ES 100KM (in Toronto) at constant speed with prior resetting the tank average when the Range number is showing an almost empty tank on 91. Then, I fill it up to the neck with 87 and run the same highway same speed to see if there are any differences between the two gas mileage figures. I figured out if the 91 gives more power then the gas mileage will be better. Do you guys agree? If the results are roughly the same, we are paying extra for nothing but helping the Lexus myth and making the gas companies to get rick faster. Are we stupid?

As well, the Lexus has a highly sophisticated computer controlled system, there should be a knock sensor or sensors to sense any engine irregularities ( as even 91 from different gas stations might vary thus affecting engine performance) and advance/retard the injection/firing timings to reduce engine knocks. Surely, we should feel it too if it doesn't correct itself. So, we pay for a great system with self-correcting capability we better use it good.

This is one way I would try and report to you all (but needs to wait as I just filled it to the neck with 91).

If everyone of us chips in ideas and test results, I am quite sure we would come out with our own recommendations fast rather than asking in the air and there is no free lunch nowhere. Doing it ourselves also give us peace of mind rather than taking other's suggestions blindly.

I just bought my 2008 ES350 two weeks ago and have been very pleased with its performance - yes, it gives effortless driving but tons of driving fun. Again, comparing to the flagship Chrysler 300M special (meant to be sporty) I had before, I have to say the ES350 is so much better, quieter, more powerful, less gas hungry, better sound quality and learns now what a "smooth ride" means.

Can we all come out with a workable and sensible plan to test the 87/91 myth using the community power here? I know many don't care the $5 extra per filling but I seriously think if I don't have to I will pick up 5 Kitkats instead and enjoy them driving in the open country for as long as I own the ES.

Suggestions please.

Lew270

I'm in...I will be testing a similar scenario...but more likely with a larger test sampling timeframe.

...also, just to be clear on my end, this is not about being cheap, it is all about total cost of ownership over the long haul. I consider the money I pay for fuel as part of that equation.

One of the reasons I spent 40k on a Lexus VS a MB, Infiniti, (or any other car for that matter) was the reputation that these things “just don't beak” (sans some outliers). I tend to keep cars for a long time.

$5 may not seem to be a lot of money at the real-time moment of a fill-up, but if you do the math (everyone’s scenario is different) over the course of 6 or 7 years, it could be a substantial amount of moola. This could equate to thousands of dollars over the years, and if I'm not harming my car by using 87, then why not put that money in my pocket a opposed to our billionaire friends at the oil companies.

Hey...Those funds could pay for a few sets of tires (Michelins for that matter) if I keep the car 6 or 7 years.

NJLEXES

The use of regular unleaded 87 octane is not going to "damage" the engine.
As has been stated, many Toyota's using the 3.5L engine (Avalon, HIghlander, RAV4,etc) were rated at 268HP. The Lexus ES350 was rated at 272HP. The difference is that the Lexus is "programmed" to take advantage of the higher octane fuel (91 or higher) when it is used. That is where your extra 4HP comes from.
I do generally use the SUPER UNLEADED in my ES350. However, when gas was up over $4 gallon few years ago, I did start using regular 87 temporarily to help save some $.
Currently in NJ, SUPER is around $3.70/gal. I still use it in mine.
Ultimately for myself, I am more concerned with the brand of gas I put in the car.
I never use "off-brand" fuels and go to stations who move alot of fuel.
I generally use SHELL, EXXON, and SUNOCO occasionally.

My manager at my Lexus dealer pretty much echoed the same thoughts. 87 will not harm the car as modern cars for many years have had "knock sensors" and do adjust automatically for the lower octance variants. Even my old 1986 BUICK GRAND NATIONAL was the same. DESIGNED to use SUPER....but COULD use regular unleaded which would give reduced performance.