Not saying that 87 is okay, or not okay, but the claims of 87 killing O2 sensors and cats... that's simply silly. O2 sensors and cats are the same, regardless of whether they are installed on a car that specifies 87 or 91 octane.

Carry on.

 

...changing in the world for sure. We need to all buckle up for this unknown ride. I can remember being a kid and gas never being an after thought. Fast forward to the present and its a main topic of convo's around the U.S and the world. Times are changing and when we talk of what grade to use as a post that is a sign that times will never be the same.

All the best to those who are having a tough time with the prices effecting not only gas at the pump but, other goods and services. Wow, times are and have changed.

L.G.N.M

 

The real issue with using a lower octane gas is when the engine is under heavy load. If you press the pedal to the floor all the time, then your risking damage to your cylinders walls.

Long term, i'm sure the engine life will be increased by using a high octane fuel.

 

my opinion stands, 23 gal tank, with 0.20 saving per tank, the saving is only less than 5.00.
To me, it's not worth it at all.

 

I don't know about the damage to engine components, but I can personally attest that using a lower grade DOES NOT reduce MPG. I had been using mid-grade (89) for quite a while and just switched to using premium in the last couple months. There is no noticeable difference in mileage. And I watch my mileage very closely.

 

Opinions may vary is certainly demonstrated here! Higher octane fuels produce a slower burn and it has been proven that using a higher than necessary octane fuel can reduce fuel economy and increase cranking times, GM and Ford have issued service bulletins addressing this back when fuels were cheaper. Now that prices are up there is probably not an issue with many using higher than required fuel octane. The basics are, lower octane produces a faster, cleaner burn. Higher octane is not "cleaner", it is simply a less volatile blend. All fuels will burn very slow in an uncompressed state, it requires air and fuel in a precise ratio in a compressed state to produce a rapid efficient burn. Cylinder walls are the strongest part of the combustion area in an engine, not likely to be damaged, pistons are the most easily harmed. Under normal driving conditions, the actual cylinder pressure is lower and higher octane is really not needed, under hard acceleration the cylinder pressures will be much higher and the higher octane would be beneficial to making slightly more PEAK power. O2 sensors are most likely to be harmed by use of a higher than needed octane fuel, no effect incurred when lower octane is used. Catalysts are the same way. Ignition timing is the only adjustment effected by use of different octane fuel and even then it's only when a substantial load is placed on the engine. Everyone is going to use what they feel is best for them. Sign me up for the 87!

 

You know what the Lexus Salesman told me? They put 87 in ALL the cars on the lot.

 

I'm not surprised, and I'm sure nobody has accused them of using 87 octane on a test drive.

I really don't know who to believe no more.

 

If that's true, it'd be just fine (at least on the new cars -- not sure about the used ones) because a NEW engine actually requires a few full points less octane than that same engine will after it accumulates several thousand miles (could be 20K or so, depending upon various factors). The reason is that Octane requirement is governed by and large by what's called "end gas temperature" which is the temperature of the burning charge when it's nearing the end of its burn cycle on the power stroke. A NEW engine that is absent the insulating deposits which normally accumulate over thousands of miles of driving will have a significantly lower end gas temperature than an older engine that has the normal deposits. Hence the engine requires significantly lower octane when it's new than it will later in life (all else remaining equal). When automakers specify the grade of fuel for a given engine, they do it based upon their testing and projections of what that engine will require down the road when it has the normal amount (or even an abnormal amount, if they are building in some extra safety margin) of deposits.

And, I'm not talking about crazy or unusual amounts of deposits -- just the normal type of deposits that serve to insulate the piston tops and combustion chamber surfaces from the flame and thereby reduce the amount of heat that is soaked up and disipated through these surfaces. Many people hear about "deposits causing knock" and think it's due to crazy buildup of deposits increasing the compression ratio, but it's RARELY like that -- it's much more often the insulating effect of the relatively thin layer of deposits.

 

Carguyin GA knows what's he talking about!
Higher compression engine needs higher octane to prevent knock. Now the computer can retard the timing to reduce knocking. So using 87 octane gas only reduce the peak engine performance. I use 87 octane in all my cars and no problem so far.

 

The funnier thing about the salesman telling me that is this was in late 2006 - when I was in the market for an 04 430. Gas was still in the 2.xx range. So these dealerships are cheap!

 

He said it was not just new, but all used cars as well that they sell.

 

of course the dealships are going to use lower octance gas. They don't really care what it does to the car as long as it runs fine when you are test driving it.

Cut costs and increase profit margins. It's not a stealership, it's a business.

 

I saw an interesting article on msn.com entitled, "Can I Use Regular Gas Instead of Premium". I believe this will answer the long-debated question of using regular fuel in the LS430.

Here's the link:
http://www.msnbc.msn.com/id/25691323/

Happy reading!

 

thanks for the article AudioBuff. Im gald i stuck with the "required" gas for Lexus. not too sure I'd wanna gamble on "somewhat limited damage by using lower premium gas. for cars that require premium."