Mythotical

Let me first say that I live at 3,00ft so it will make a difference. I use 87 and most of the dime I drive my 98 es like I stole it, but I still average between 15-17 (summer gas) and have seen as low as 12 on winter gas. When I can keep my foot out of it and drive like a normal human, I have achieved as much as 30 mpg and I drive about 90% city.

I can get ethanol free in 92 and 101 only but I have not tried it yet. I want to try a tank full of 101 when autocross is back in town again. I'll post my results after.

Hope this helps.

PuReChaos

Lucky you, it must not take you 45 minutes to drive 6 miles.

Hayk

iTrader: (1)

This is a common misconception. All gas is equally pure.

From what I've seen, engines that have an 11.0 to 1 compression ratio will require Premium (91+) gas*. Engines below that number will recommend Premium gas. The ES300 does not use a high compression engine, so the performance difference between 87 and 91 seems to be negligible.

*Not always the case, especially with economy cars.

hypervish

It does, 10.5:1 is high compression and therefore warrants the use of high octane fuel.

That is all I will say, as there are hundreds of threads floating around on this topic both in the ES & RX300 forums.

dlamb89

Thank you everyone for your useful insight. You all helped a bunch. I known there are many threads on this, but never found one that explained it on multiple ends like you all have. So I'll try 91 since I do a lot of highway driving, and since the compression ratio is higher. Hopefully its the sweet spot.

01LEXPL

iTrader: (10)

HWY 91, city 87 - especially in the winter.

I wish I got as high as 15mpg... 10-13 all. winter. long.

285exp

In your original post you said:

Both were done with the same driving habits, both filled up full. So, why do I get much better MPG with 89?


Since you were effectively just guessing on how much fuel you used, your loss of mileage is just as easily the result of poor guessing rather than any actual difference in economy. When you say that your performance is better, how did you measure that? 0-60 time? Seat of your pants?

Last year when we had one of these threads I decided to run a test for myself. I have a 97 ES300 that I have owned since new. I have been using regular 87 octane the whole time. I mostly use this car for commuting to work, and I take the same routes at the same time of day pretty much all the time, about a 50-50 mix of interstate and city driving.. I filled the car with premium 93 octane for 4 consecutive tanks. Below is a graph of the mpg of every tankful of fuel I have put in the car since Jan 2013. Guess when the test was performed.

BDSL

Nice. So you went from roughly 21mpg to 25mpg...20% increase (or decrease) depending on which way you are looking from.

285exp

You guessed incorrectly.

285exp

You can disregard the big spike in the middle, that was a 425 mile trip that was 90% highway. The test was done in calendar 2013, so you can disregard the last 3 months. It was 4 tanks of gas, so it covered about 2 months, and each unit on the bottom scale is one month. If you're curious which months were on premium, use the search function and type seats and octane, that will show you when it was done.

Mythotical

Ok so I finally got my 98 es to ping on 87 octane yesterday, after sitting in traffic for a while I hit the gas hard and got a 2 second long chain of pinging. Here is why I have relocated and singled up a knock sensor onto the end of the forward head and after sitting at a standstill in traffic with the AC on in 91 deg heat with 40% humidity at 3,200ft with my intake temp sitting at 220 deg I got a ping. I hit a red light a half mile down the road, stopped for 20 seconds, my intake temp fell to 183 deg so i hit it again and no ping... so it takes a lot for the 1mz to ping, even if you re locate the knock sensor.
So as long as I keep my foot out of it when the intake temp nears 200 deg I will happily keep using 87. Also valve, piston and engine deposits are for people who drive like they have no place to be. Floor it once in a while and you will never have to worry about deposits in your engine, with regard to intake manifold gunk. So you can take your "premium gas burns cleaner" crap and eat the cost with it! As a mechanic I have taken apart lots of engines and have found engines with deposits are usually driven by the slow moving.

P.S. I drive quite spiritedly and still I get an average of 28 mpg mixed on 87!

Hayk

iTrader: (1)

How is your intake temp so high? Did you modify your air intake piping to suck air from under the hood?

ES300NZ

In New Zealand, we have 91 Octance as the lowest rating, 95 Octance, and 96 Octane, with 98 Octane available at three companies. One company sells 98 (actually 102) Octance with 15% Ethanol. In terms of price it's all pretty much in the same price range, $1.68 for the 91, and around $2.20 (per Litre).

Toyota New Zealand says to run either the 98 Octane Fuel, or the 98 (actually 102) Ethanol in the blend, with 95 being the least recommended permissible fuel.

BDSL

I believe you guys are using RON....where as in America, we use AKI.

ES300NZ

http://en.wikipedia.org/wiki/Octane_rating