Premium Gasoline Question

[Duckman]

I have been filling my car with standard unleaded gasoline, 87 octane. Now...I am doing this because I have seen news reports that the 92 octane premium gasoline is not worth the extra money. Reports done in Minnesota news have concluded that it is more marketing than substance.

So, this week I was speaking to my father. He is a car guy. He has an Audi S8 and an Audi S6 (which he races...oh yeah...it's a fast car). He said that he fills his cars with premium only. That the premium gives him a substantial difference in engine performance. I asked him if I was damaging my engine by filling it with regular, and he said no, but I am not doing what is best for the engine in my car. He suggested that a good compromise would be to fill it with premium, then go with a mid-grade on the next fill up, then premium, and so on.

This evening I filled it up with 92 octane premium. Ugh...nice price on that one.

What are your thoughts, does premium make that much of a difference? Does it damage the engine to use regular unleaded?

--Duckman

[Duckman]

Got it....I took the time to search the forum and found this post:

http://us.lexusownersclub.com/forums/index...showtopic=30609

--Duckman

[The G Man]

Your GS300's engine have a compression ratio of 11.5 to 1. That usually means you should be using premium gas. You can use the cheap stuff if your engine doesnt knock, but you will lose horsepower and gas mileage. Going from premium and regular every other tank is ok as long as you fill it up around at 1/2 tank. If you wait till its empty, you will not get the full horsepower benefit from the premium tank since it takes a few tank full for the timing to advance.

BTW, the reports on Minnesota news is for cars that do not require premium and cannot take advantage of the extra octane, but thats not the case with your GS.

[Duckman]

Thanks G-Man. I have had the car since last August and had never filled it with premium until last night. I am going to bite the bullet and fill with premium exclusively now. I am assuming that by making the switch, my engine performance will increase with the first tank.

I don't have any loud knocking noises, so I can only hope that I have not done any damage to the engine.

--Duckman

[Step Hen]

Might want to check octane ratings around you as some states have some mid grade gasoline that is not premium but above the necessary rating recommended for your car. The difference between regular and premium isn't that great per fill up. Extracting that over a year, the difference isn't really worth the decreased engine performance / worse gas mileage.

There are better ways to save money.

[The G Man]

Duckman, it will take a take a few tank full b 4 u will feel the slight diff. in power. I dont think you have done any damage to the engine since it will adjust timing when it sense knocking from the lower octane.

[jeffl]

I run my GS300 on 89. I have tried 91 and 93 but see no noticeable change in performance. They key is that the engine cannot ping which wrecks havoc.

[The G Man]

I ran on 89 octance on my last Lexus for a while. Its kind of pointless since you only save about a dollar on every tank full.

[Flynlow]

You gave up the green for the car and now your cheating it? That computerized gas burner has a preference that it needs to run effectively and efficiently with. Try cutting corners with the wife and see what I mean.

[The G Man]

Good thing my wife runs on 87 octane :)

[Mad Dawg 350]

You gave up the green for the car and now your cheating it? That computerized gas burner has a preference that it needs to run effectively and efficiently with. Try cutting corners with the wife and see what I mean.

Good thing my wife runs on 87 octane :)

Mine runs on nitro methane!!!!!!!!! :D

[gemgem]

I saw a video on www.expert village, that says if you add a small quantity of pure acetone to 10 gallons of gasoline, you will increase your mileage by quite a bit. The acetone helps burn fuel more efficiently.

[The G Man]

Acetone is a solvent, adding that to your gas is a bad idea since acetone is corrosive. It will eat away at your o-ring, gaskets and rubber gas line.