Anyone running 89 or 91 octane?

[Gurvy522]

Eh, I think it's all circumstantial. Is the truck working hard, pretty much boosting all the time to stay at speed? If not, I'd think regular is fine.

Once you're at speed, at a level altitude, the truck (and trailer/gear/etc) is mostly fighting drag. Obviously up grades you're fighting gravity.

When I did my first haul of my trailer (4300lb 20ft camper) with the new truck, I noticed the truck was pretty much stuck in boost at around 60-65mph. And it was even more prevalent in a headwind. Going up a slight grade, just maintaining speed, full boost. So I realized quickly that premium might be a good insurance policy more than a strict requirement on a long distance trip.

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[Cabby30]

I’ve been running 89 for all ~5k miles. Mpg‘s have averaged out at 19.5mpg in that interval with my commute being about 60/40 (hilly) highway/city 70mph cruising speed.

Probably will continue running 89 for the foreseeable future. I haven’t done any math on this.

I‘d like to see someone try different octanes on a dyno.

 

[Baltimore]

Not sure why anyone is claiming this isn't listed. It's clearly stated in the owner's manual on page 584 (hybrid manual).

Fuel
Fuel type Unleaded gasoline only
Octane Rating 87 (Research Octane Number 91) or higher
Fuel tank capacity (Reference) 18.2 gal. (69.0 L, 15.2 Imp.gal.)

And on page 591
Fuel information You must only use unleaded gasoline. Select octane rating 87 (Research Octane Number 91) or higher. Use of unleaded gasoline with an octane rating lower than 87 may result in engine knocking. Persistent knocking can lead to engine damage. At minimum, the gasoline you use should meet the specifications of ASTM D4814 in the U.S.A.

Additional (whatever thread debated detergents and ethanol), same page 591

Gasoline quality In very few cases, driveability problems may be caused by the brand of gasoline you are using. If driveability problems persist, try changing the brand of gasoline. If this does not correct the problem, consult your Toyota dealer. ■Recommendation of the use of gasoline containing detergent additives ●Toyota recommends the use of gasoline that contains detergent additives to avoid build-up of engine deposits. ●All gasoline sold in the U.S.A. contains minimum detergent additives to clean and/or keep clean intake systems, per EPA’s lowest additives concentration program. ●Toyota strongly recommends the use of Top Tier Detergent Gasoline. For more information on Top Tier Detergent Gasoline and a list of marketers, please go to the official website www.toptiergas.com. ■Recommendation of the use of low emissions gasoline Gasolines containing oxygenates such as ethers and ethanol, as well as reformulated gasolines, are available in some cities. These fuels are typically acceptable for use, providing they meet other fuel requirements. Toyota recommends these fuels, since the formulations allow for reduced vehicle emissions. ■Non-recommendation of the use of blended gasoline ●Use only gasoline containing up to 15% ethanol. DO NOT use any flex-fuel or gasoline that could contain more than 15% ethanol, including from any pump labeled E30 (30% ethanol ), E50 (50% ethanol ), E85 (85% ethanol ) (which are only some examples of fuel containing more than 15% ethanol). ●If you use gasohol in your vehicle, be sure that it has an octane rating no lower than 87. ●Toyota does not recommend the use of gasoline containing methanol.



There's also multiple threads on guessing the low fuel level reserve when this is also called out in the manual on page 546

Low fuel warning light Details/Actions Indicates that remaining fuel is approximately 2.7 gal. (10.4 L, 2.3 lmp. gal.) or less Refuel the vehicle.

 

[Deleted User 1813921]

Here in Pennsylvania the pumps have 87 octane I am not sure what the mid grade is? And 93 octane. I have been running 93 and it is a noticeable difference in performance from 87. That’s a big jump in octane. We have 90 non ethanol available everywhere. In oil city where they refine fuel I found 93 non ethanol at a car wash gas station while motorcycling. With Toyota having tuned the truck for 87 it’s kinda personal preference to run higher octane. As someone mentioned dyno figures with different octane would be interesting to see. Maybe I am feeling a false sensation of higher performance?

 

[diablo2112]

I have been running 93 and it is a noticeable difference in performance from 87. That’s a big jump in octane.

By what mechanism do you think higher octane is improving performance? It's not energy content. Higher octane is marginally lower in energy. This is a common myth. Higher octane does not improve performance or gas mileage. All it does is reduce knock in certain engines with delayed timing and high compression ratios. Otherwise, it's all just marketting bologna.

 

[Deleted User 1813921]

By what mechanism do you think higher octane is improving performance? It's not energy content. Higher octane is marginally lower in energy. This is a common myth. Higher octane does not improve performance or gas mileage. All it does is reduce knock in certain engines with delayed timing and high compression ratios. Otherwise, it's all just marketting bologna.

Going from 87 to 93 I felt a seat of the pants difference. The same difference I feel when I run race gas versus pump gas in my motorcycles. I can feel it! It sure feels real. I am talking about leaded race gas in dirt bikes and unleaded race gas in sports bikes. My personal preference is to run 93 octane in the 24 Tacoma. not wanting to go back and forth here about fuel theories. I will bow out. Thank you.

 

[32spoke]

Unless someone is able to prove that the ECU has timing “float” for ignition, then there is a chance that higher octane can produce better power and possible mileage based upon the ecu’s ability to midly increase “float” ignition timing to detect if continued spark advance is acceptable due to fuel quality. Alcohol is fuel requires much more fuel to make power- less BTU. Race fuel, like MS109, are physically lighter than pump gas, and create lots of power. Lead in fuel doe not great power, it is a “padding” for engine valves but not compatible with oxygen sensors and catalytic converters. So unless the ECU can float timing, I don’t see how increased octane can make more power unless alcohol is absent from the fuel mix. As posted earlier- lower octane is more prone to pre ignition and detonation when the combustion chamber is being subjected to a higher stressed environment- like wide open throttle… my 2012 Audi has timing float. Bosch MED ecu-

 

[Gfenza89]

Way more important then octane is running top tier gas. Keeps the back of the valves clean and entire engine. Thank god for Toyotas d4s we get the best of both worlds and using top tier fuel helps the d4s system keep those intake valves even cleaner and combustion chamber

 

[Gurvy522]

Way more important then octane is running top tier gas. Keeps the back of the valves clean and entire engine. Thank god for Toyotas d4s we get the best of both worlds and using top tier fuel helps the d4s system keep those intake valves even cleaner and combustion chamber

Toyota really learned their lesson with the 4GR.

 

[Cabby30]

Stillen reporting 20HP difference between 87 vs 91 octane.

 

[timetoeatpotatoes]

It runs boost and higher compression; I run high octane fuel.

Sure, modern ECUs can retard timing to prevent knock, but I'd prefer to just....run the right octane in the first place. And probably we will get a tune specific to 91 down the road.

 

[Daveintb]

I use 89 octane Chevron or Shell all the time.

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