Mythotical

I use 87 and the car runs great. I also live at 3,000' so that may be a factor.

tomf

Here is the last page from my 99 ES300 user's manual. I don't know how you interpert it but to me it's clear that 87 octane gas is recommended for daily use. Of course the 1mz-fe engine in the 2002 model could be different than the 1mz-fe engine in the 1999 model.

BTW in Nebraska I have a choice of 87, 89 ethonal blend, or 91 octane gas. I use 89 octane because it's cheaper than 91 and as far as I can tell there is no difference in performance between the two octanes. One gas station claims to sell 93 octane but again I noticed no difference between 89 and 93. I am skeptical that it was actually 93 octane gas.

brucelee1

iTrader: (2)

Really, how much money do we need to "save" on gas?

tomf

Who is this "we" of which you speak?

285exp

How much more do we need to spend if there's no significant benefit in doing so?

Power6

This one is going to rage on forever. I think we can safely say it doesn't matter much. All the evidence has been presented. Nobody is cracking pistons from 87, and nobody is winning races with their 91 octane. This is the proverbial mountain from the mole hill. For the normal people just do what makes you feel good.

Now back to your regularly scheduled pedantic arguments and doomsday predictions...

Mythotical

Ok so I have to put in my two cents in here but with a little story first. I just bought my 98 ES300 with 199,740 miles on it and the oil pressure light flickering. Needless to say and to make a long story short the engine was sludged really bad, then it lost oil pressure on the highway and evaporated the #1 rod bearing. (saw this coming) I got the car in less then perfect condition and really cheap. I am a mechanic and had already priced out a junk yard pull for $400 long before buying the car. I overhauled the junk yard pull and did it for less then I would have spent on rebuilding the original engine before it spun. When the engine did spin I had just tanked it up on 87 because I knew it was on the way out anyways. So after getting the car back together the thing just pulls hard as hell. Now I just emptied the tank yesterday and thought I should start the switch to 91 so I tanked up on 89 and now I have a lot less power and I wonder what will happen on 91. I also think that having reset the ECU there is a chance that it has not completed all of its drive cycles. The next time I drive it I will check that with my tablet and TORQUE. I'll keep you posted.

rlx101

exactly my point. there is this common thread amongst lexus owners where they somehow feel like they belong to the elite club and if you put regular gas or replace brake pads with regular off the shelf stuff you are somehow braking their elite club laws. there is no common sense left what so ever.

Bdub215

iTrader: (1)

Until someone hits a dyno all everyone here is just doing is just really talking out of there ***. I have a 93 octane dyno for a VVT-i 1MZ-FE sitting next to me. Now who wants to go do one on 87 octane? Or do I have to hear something along the lines of "what will that prove?" Put up or shut up time. It's not that hard.

Mythotical

FWIW here is the best reading on the subject of octane rating and ignition timing I can find on the web.

http://www.innovatemotorsports.com/resources/myths.php

285exp

If you want a useful comparison, you'll need to do it yourself. Someone else doing it with their car would prove nothing, as the engines are not identical, even when they were brand new.

And the only thing it would prove if you did would be how much additional power premium gives your car at WOT, which is of relatively little use in real world situations.

I've been using regular in my 97 ES300 since I bought it new. Out of curiosity, a couple of months ago I used premium for 4 consecutive tanks of fuel to see how much better mileage it got. The prior 4 tanks of regular averaged 20.7 mpg. The 4 tanks of premium averaged 21.2 mpg. The last 5 tanks using regular again have averaged 20.2 mpg. So, overall, I gained around 3.5% in mileage. Premium cost me around 8% more. From a purely economic standpoint, it's a waste of money for me to use premium.

Mythotical

Ok I agree I am going to continue using 87 and leave it alone unless I have to take a trip down to sea level on a hot day. I live and work at 3,200' and even tho I have relocated and singled my knock sensor to the side of the head I could not get it to ping or knock if I tried even in 98 deg weather with 7% humidity. And finally the 91 in Missoula Mt. sucks *** and all of it has 10% ethanol added so screw it. I am happy with 87 and I will take it to the track too.

Hobbitt

Hi octane does not mean more mileage. Hi octane merely means smoother burn. Gasahol says higher octane (a cheap way to do it) and gas will always get better mileage than gasahol.

Also, if you are at three thousand feet your car will see 89 octane drive just like 91 octane would at sea level. If you drive as a normal person 87 does not hurt anything.

Power6

You are confusing two concepts, normal Gasoline gets better mileage than Alcohol blended Gas because Alcohol is less energy dense. Octane rating is actually resistance to combustion, a measure of stability if you will. It plays into ignition timing, if an engine control is programmed to take advantage of it. Energy density is a different concept.

There is basis that you can get better mileage through higher octane, advanced timing can be more efficient, therefore more energy to moving the car and less wasted as heat. 285exp showed us this with his informal experiment, and also he showed us the economics don't really work out when you figure the increased price of the higher octane gas. If he would have changed from a pure Gas product to an E10 say, that would not have worked out the same way.

dlamb89

As stated in the title, what are the advantages and disadvantages of each? For example: performance, fuel efficiency, speed of engine wear etc