I run premium because the original 1GR-FE was designed for it and the white paper on the engine said it got 285 hp on premium versus 270 on regular.

I've been a 1GR owner since 2010 with the single VVT-i engine in my Tacoma and now the dual VVT-i engine in my 2019 4Runner. This same debate has been going on since before I was around but no one has ever posted real proof other than "it feels faster" butt dyno charts. It also doesn't help that at one point Toyota did mention running 91 but then removed it from the manual probably because they changed their tuning.

There’s just not anyone willing to conduct this type of testing, over this extended period, for a *potential* 1-2 MPG increase when the sheer price of premium will more than consume any savings. In my area, premium is about $0.60 more than regular.


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I've started buying Shell from Circle K and I've noticed my Spotify is giving me fewer advertisements and is repeating my favorites more often. I need to try this out for another week or two but signs are promising so far.

Even "smart" cruise control is a blunt instrument for an underpowered engine. On a flat Interstate, CC works nicely. On hills, I found it sucked big time, double downshifting way more than when I tried a similar hill without it.

Octane aside I think a better thing to consider is getting fuel with zero ethanol garbage in it. Also not all brands are the same gas wise, some discount places have old shit watery gas with likely lower octane that may retard timing

Ideally go to Home Depot, get a box of mothballs..preferably very old stock made in the 1970s... use sparingly as they can clog injectors over time... a ball here...a ball there..

Or say **** it and go big....go Toluene. Try not to get high or go blind or melt anything plastic while your dumping it in..

Ethanol is an octane booster. It's why guys with modified turbo engines often run high ethanol/gasoline blends and/or full E85. You can often find an extra 5%-10% of power and better pre-detonation control on a turbo motor that is tuned to handle a high ethanol mix.

The biggest issues with ethanol as a fuel are:

- It has a lot less energy thus reduced MPGs. Running full ethanol will result in ~20-25% lower fuel economy than full gasoline.

- Ethanol is hydroscopic, thus takes on moisture if the ethanol sits in your gas tank too long (i.e., 1+ months).

- Ethanol being better for the environment is a total and utter farce. It is misguided, a complete waste of resources, and is very energy intensive to produce. And this is coming from a guy that's been doing environmental consulting since 1998.

With respect to premium resulting in better driving and mpgs in these trucks, I'll just say that the power of suggestion is a very powerful thing to one's mind.

I've seen this discussion/debate time and time again on the automotive forums I've been a part of since the days of dial-up and America Online (AOL).

It really makes no sense for the truck to have better throttle response and less downshifting running premium. Octane is a fuel's resistance to burn. Thus, higher octane fuels are more resistant to burn which is why they are required in motors with really high cylinder pressures. The current gen 1-GR isn't that motor. Plus, the benefits of higher octane would be present under hard, high rpm driving, and not low rpms or initial throttle tip-in.

As for downshifting, that is all related to engine vacuum and load and not octane. The transmission ECU senses a change in engine vacuum and/or load (i.e., higher load) and will downshift accordingly. It has nothing to do with octane.

If someone wants to really put this to the test. Take your 4Runner to a shop with a Dynojet dyno. Do 3 runs with 91 for about $100. Then full up with 87 and run that for a week or so and re-dyno on the same dyno and similar ambient conditions. I would bet the HP and TQ numbers across all runs would all be within 1-2% of each other which is typical dyno run variability.

Lastly, the higher the altitude you are, the less octane the motor needs (low oxygen in the air). That's why in high elevation areas you routinely see 85 octane fuel at pumps. It's not because the stations are "cheap".

Just for the sake of accuracy, it's 'hygroscopic'.

A friend who is a retired engineer who worked in the automotive industry for years says that premium fuel creates less heat in the combustion chamber vs a lower octane fuel. That said I run it when I know I will be doing Long climbs in the Mtns out west here. So it is possible it could keep engine slightly cooler? I am also a firm believer in non ethanol fuel and run that whenever possible. It may be even more beneficial than the premium👍

I've been running premium for 5 years and feel like the truck just drives better with it. Granted my ECU is now tuned to run on 93 and the power gain is extremely noticeable, but after a few tanks of 87 when I bought the truck I felt that the gas mileage and overall performance of the truck was always better on 93. To each their own

i get 10.5 mpg on mixed driving.....


i gave up trying to get better gas mileage a long time ago...

This. My truck hunts between 4th/5th so much when I turn on cruise control that I just put it in 4th and leave it.

I understand the above, was referring to what you posted on its diminished power output in comparison with petrol. Ethanols calorific output as likely you are quite familiar with is quite low in relation to other such fuel alcohols.

I am not in favour with how its produced either, with wasteful corn and such. It being hygroscopic likely more an issue during storage and transport as most consumers tanks dont last to long. But it also means the likehood of you getting shit from the pumps with a high ratio blend is higher than just an unblended gas.