zylomoto

what gasoline octane should i run in my 2002 430ls

05ls430518

iTrader: (1)

91 and up I run 93 octane

Bocatrip

91 minimum if you'd like your car to perform as it should. Many posters will tell you how they run their luxo cars on 89 and it runs fine. Bottom line that is not what the manufacturer suggested and although it will run, but without the power output it was designed for, and with a loss of gas mileage. Your choice....I treat my car better than I take care of myself. 91 octane for the last 9 years with an occasional 93 when the station doesn't have anything else (over 91 won't make any difference in performance or gas mileage). There are many posts on this subject, but if you care for your car it will perform as designed with the recommended octane of 91 minimum...

bradland

In layman's terms...
Higher octane fuel doesn't necessarily mean "better" fuel economy or more horsepower. 93 isn't "better" than 87 but it does burn differently in the combustion chamber. The rate at which a certain fuel burns, lets say 91 octane, is intended to match the compression ratio of your engine as close as possible. An LS430 has a compression ratio of 10.5:1 which is higher than most cars on the street. This is exactly why Lexus recommends using at least 91. If you drove a Toyota Corolla you would be fine using 87 and using 93 would provide no advantage. It's what the engine is designed to burn.

Jabberwock

My LS430 runs just fine on 87 octane (US gas octane rating) and also runs just fine on 91 octane. I tend to use mostly 91 octane especially in hotter weather but the car's engine computer seems to be able to adjust to working with 87 octane seemingly without issue (at least with the kind of driving I do which is 90% Grandpa style gentle driving). Obviously if 91 was same price at 87 I'd always run 91. I fill up every 2 weeks or so, some weeks I feel cheap for unexplained reasons, and so I run 87 for a tank, doesn't seem to affect or hurt my car, but I have zero objective measurable evidence on any of this - just general impressions. Car has 104 k at this point and runs smooth as silk. Likely have run 87 about 20% of its total fuel fills.

05ls430518

iTrader: (1)

As long as you do not put diesel or e85 in your car you are fine 85-93 octane is fine. Every cars ecu has a variable of about 10%-20% were it can adjust fuel, spark, timing etc so the car does not blow up.

Johnhav430

This thread is full of informed posts, seriously. All correct. For me, I run 93 because it's available, and for whatever reason, the price is reasonable--30 cents more than regular. And I don't know what happened--the warehouse clubs are no cheaper right now than some gas stations on my way home, $2.799.

Like others have said, octane is not a measure of goodness etc. It's predetonation/ability to resist it, and the only way our cars do 278/312 or the old rating 290/320 is with 91 octane. So if you use 87, provided the knock sensor is good, the only thing that will happen is the motor will not make the advertised numbers.

I ran my 1998 Maxima on regular 87 for 20 years, nothing happened. I just didn't want to pay for premium in that case. Now there was a shadow code where my knock sensor was bad--until I got it fixed, I did run premium in the Maxima. Once fixed, back to regular.

Legender

No only octane, but consider the top-tier gasoline stations. It is recommended that they have better/cleaner gas that is better for your car based on a joint study by AAA and CR.
Check here:
https://www.consumerreports.org/car-maintenance/study-shows-top-tier-gasoline-worth-extra-price/

and here for the list of stations:
https://www.toptiergas.com/licensedbrands/

And I realize, that while we are driving a high end luxury car... some of us are just real tight with our money

bloomwcjkl

I do 93 Premium in all our cars. $4 more per fill up. 2 or 3 fillups per month on 2 cars. Not going to make/break our retirement.

I don't notice any difference if I use 91. If I use 87 I can tell the difference. Not quite the power and not quite as smooth. Some use 87 all the time.

2KHarrier

I guess I'll chime in here... Driving as much as I do and filling the car up 2 times a week, I tend to try to keep things on the less-expensive side. 90% of my driving is on the freeway cruising at 70-75 mph, so for a long time I was running regular with no adverse effects. I've switched to 89 recently to see if my long term MPG would increase, which it really hasn't. I still average 26-27 MPG on my commute, although I just swapped the snow tires out for my Pirellis, so I should see a slight increase in the average mpg.

Short answer, I run mid grade and the car is happy with it.

Johnhav430

A brochure came with my brand new 2007 BMW, in 12/06, "BMW recommends Top Tier gasoline." My response? PFFFFFFFFFFFFFFFFFFFFFTTTTTTTTTTTTTTTTTTT! lol

Over the years I have changed, yes, I would rather have Top Tier if it doesn't cost more, and it DOES NOT with Costco and Citgo.

I talked to the owner of an Exxon dealership and he explained, what happens at the terminal when the tanker gets the fuel. Yes, there is something to Top Tier. What? Hard to prove, but as I've said, if it doesn't cost more at Costco or Citgo, why not?

Oh yeah and I've been on the BMW forum so long, I remember the, "If you buy Costco gas, you don't deserve a BMW." Whatever dude!

Legender

Even Quick Trip has top tier now... I think most but Race Track are top tier based on the list. I just feel better when I use the good stuff. Just like I feel better when I drive the Lexus. Makes me happy