Funny you happened to ask. I was just googling Tolulene last night looking for a cheap octane booster.

Shell gas only. 87 is okay, but I really notice a benefit using 91 octane around town. I'll have to try 89.

In all honesty tho, my LTFT numbers are in the 13-15 range (both bank 0 and 1), so I've got something going on that's keeping my engine from running at peak efficiency. I'm getting ~30 MPG/Hwy which is pretty good for an engine only doing 165psi on it's compression test. Needing Scanner Danner (YouTube) to diagnose it but I'm on a Tin Canner budget until things get back to normal.

 

89

I put 87 for a stretch and the car ended up in the mechanic's shop. He charged me a couple hundred to change some part

If that was for a knock sensor, about the only thing that might complain at 87 octane, you got a hell of a deal.

Meanwhile, we've used only 89 at so-called top-tier gas stations as a way (maybe rational) to avoid the 1mz-fe over-sensitive knock sensor problem and (very likely irrational) prevent the sludge problem. Lower octane probably has no contribution to sludge...

 

@abacus32 I've tried STP's octane booster, meh...I'm on the fence with additives. I'm really surprised you get 30mpg though!
@OleAvalon not quite sure, I know I changed out the knock sensor a while back though. Correct me if I'm wrong, but I could have sworn that I read in my manual Toyota calling for 89 octane and above to be used. That's probably the reason I was initially using 89. I'd prefer to be able to use the cheaper stuff since I drive/accelerate pretty slow. I leave a few minutes early to get to my destination so I can enjoy the ride with windows open and music on

 

I could have sworn that I read in my manual Toyota calling for 89 octane and above to be used.

The relevant passage in my 01 Owners Manual:
"Fuel type: unleaded gasoline. Octane rating 87 (Research Octane Number 91) or higher. For improved vehicle performance, the use of premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher is recommended." (p. 199 -- p. 210 in our 03 manual)

There's a subhead, "If your engine knocks..."
"If you detect heavy knocking even when using the recommended fuel, or if you hear steady knocking while holding a steady speed on level roads, consult your Toyota dealer. However, now and then, you may notice light knocking for a short time while accelerating or driving up hills. This is no need of concern [sic]."

I think one of the posts I read early on when I joined TN was around the knock sensors, how sensitive they are, and how expensive they are. It was that last point that caught my attention. I am terminally cheap. Pretty sure I decided to pay more for 89... by now, of course, I've probably paid enough more for 89 to buy a set of knock sensors...

 

87 octane works just fine in my 2000 XLS with 95K miles.

 

I frequently use 93 octane, I’m not always sure I feel the difference, I’ll try to fill up with 87 at 1/2 tank so then I’m probably running like 89 on that tank. I also use Lucas fuel system conditioner frequently. I buy the gallon jug and refill the small bottles I have saved, the gallon is like 26 bucks at Wally Mart. I have 163000 on my 2000 XLS, it’s runs excellent. I don’t mind the added price of premium from time to time, the manual does say for added performance. I’m quite happy with my Avalon, I’ve had it almost 2 years, it does not burn a drop of oil, it doesn’t smoke at all. I think the 1st owner may have gotten a free short block due to sludge, my engine block looks like newer aluminum than the heads and transmission. I couldn’t go back past 2009 on Toyota owners site when I bought it.

 

I am very accustomed to Premium having owned several Mercedes, so I don't mind filling with premium simply because I want everything my engine is supposed to offer.. and at the end of the day it's a few bucks more per tank. I don't put too many miles as it is, so it's not a big deal for me.

 

If you can find it, I suggest that the Avalon (and most other older vehicles) runs best on Non-Ethanol gas. At one time 89, and 93 Octane were Non-Ethanol fuels. I don't believe that these grades are Ethanol Free are any longer. While some gas stations have Non-Ethanol gas, all marinas do.

 

If you can find it, I suggest that the Avalon (and most other older vehicles) runs best on Non-Ethanol gas.

Found a station nearby that has it! I wouldn't mind guinea pigging my Avalon
Perhaps this weekend; will report on my results if I do.

 

85...

 

I am quite surprised by how many people throw premium in their car.
@OleAvalon looking at some of the old mechanic receipts for my car, the knock sensors were replaced. Seems to be an issue ☹.
@abacus32 I've been checking the mpg lately...ranging between 20 to 29. Wondering if 93 will make any difference?
Have a great weekend fellas

 

Only car I've ever used 91 premium was my '85 Porsche 944 because that's what it was designed to run on. My TAL was most likely run on regular ethanol laced fuel by the one and only previous owner. and it had 107K Miles when I got it. So it drank a lot of ethanol.

 

Toptier fuel always

Non-ethanol is not toptier, even when sold at a toptier station. Alternate among gas stations and always wonder how many non-ethanol stations are honest.

Best MPG comes with (un)common sense driving techniques.

Monitor your knock sensor, timing, and A/F ratios... could help you determine if you need more octane or not.

All of my Toyotas always ran best in the summer with premium fuel. It had nothing to do with MPG. It had everything to do with being able to pull away from a stop light when its 100F and there are some people/stuff in the car. Regular was a dog and very noticeable drop in performance.

Some 3.0/3.3 years seems to run better on premium because of an overly aggressive ECU response to vocal knock sensors. Maintain your cooling system would be smart.

Octane boosters don't help much. Would need a large dose to increase octane in a full tank of gas. Not feasible.

Water/methanol injection, while expensive, is best bet for detonation control, especially if you're a cheapskate and don't want premium fuel.

Any knocking is a need for concern. Marketing control of owners manual is a fools bet. Love the 'improved vehicle performance' statement in the manual... nothing new and surprised they'd use it, with the typical cheapskate US consumer.

I have a turbo highcompression GDI engine designed for 87 and its a dog in the summer because of power loss from knock sensor shenanigans. The normal braindead zombie commuter consumer is OK with that. I only run premium.

 

I have high performance spark plugs in my Toyota Alvolon I use 93 octane

 

Regular 87 octane in my 2000 XLS & Premium 91 octane in my 98 Volvo S70 Turbo.

 

I run “regular” in my ‘96. At my altitude, regular is 85 octane.