Premium fuel 91 octane gains 20 hp / 14 lb-ft torque (vs. 87 octane) on gas engine 2.4L i-Force -- dyno test

[Henry]

This was just posted by STILLEN. Impressive power gains (+20 hp / 14 lb-ft torque) just using premium gas (91 octane) vs. regular gas (87 octane).

BTW Toyota's official specs recommends regular fuel for the 2025 4Runner, so it's absolutely fine running 87 octane.

87 vs. 91 Octane Fuel: STILLEN’s Kyle Millen reveals how fuel octane impacts the Tacoma’s 2.4L turbo engine, showing a 20-horsepower gain with premium fuel. Learn about octane ratings, real-world dyno results, fuel costs, warranty considerations, and why 91 or 93 octane is essential for maximum power, efficiency, and engine longevity—especially with TruControl or other performance upgrades. Don’t miss this must-watch guide for Tacoma owners!​

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Key Topics Covered:​

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What is octane, and why does it matter?​

Impact of fuel quality on turbocharged engines.​

Dyno-tested results: 87 vs. 91 octane on the Tacoma.​

Why cheap gas could cost you more in the long run.​

STILLEN's official fuel recommendations.​

 

[olefriend]

Good to know and interesting stats. Nice to see that any 2025 4Runner owner who wants a little oomph can just fill up with premium gas and the factory software will up the power.

Some people might interpret what they say in the video to mean that running 87 octane regular gas is somehow bad for the engine. It's not. Toyota engineers tuned the engine for 87 so I doubt it's making less power due to knock and pulling timing. It's just upping power when it recognizes higher octane premium fuel is being used.

 

[AkiosFavorite]

This video does talk about using 87 might hurt the long term reliability of the engine. I wonder if that's true, will need to see some work truck Tacoma and see if they are able to push to 1/4 million miles with just regular gas

 

[TN Vols]

This video does talk about using 87 might hurt the long term reliability of the engine. I wonder if that's true, will need to see some work truck Tacoma and see if they are able to push to 1/4 million miles with just regular gas

I very much doubt it. I don't think Toyota would be recommending regular gas if it was going to hurt the reliability of the new 4Runner. Like @olefriend mentioned, surely the engineers must have the software/engine tuned so that it runs well on 87 octane, without knock, running rich, pulling timing, and other bad stuff.

 

[AZTrail]

In most cities, regular gas is 87 octane. But cities at higher elevations (>5,000') regular gas is typically 85 octane. Is it OK to use 85 octane at higher elevations?

 

[AkiosFavorite]

I very much doubt it. I don't think Toyota would be recommending regular gas if it was going to hurt the reliability of the new 4Runner. Like @olefriend mentioned, surely the engineers must have the software/engine tuned so that it runs well on 87 octane, without knock, running rich, pulling timing, and other bad stuff.

yeah, there are more and more turbo charged engines these days can run regular fuel and I'm sure it's just fine

 

[AkiosFavorite]

In most cities, regular gas is 87 octane. But cities at higher elevations (>5,000') regular gas is typically 85 octane. Is it OK to use 85 octane at higher elevations?

Nope, that kind of lower octane is okay when naturally aspirated, not when it's turbo charged or super charged, stick with the octane rating required.
Although I won't be surprised if many people didn't know about it and still put 85

 

[qtb007]

Nope, that kind of lower octane is okay when naturally aspirated, not when it's turbo charged or super charged, stick with the octane rating required.
Although I won't be surprised if many people didn't know about it and still put 85

The spec sheet does state "regular" from Toyota. Not sure what the owner's manual will say, though.

 

[Administrator]

The spec sheet does state "regular" from Toyota. Not sure what the owner's manual will say, though.

For reference -- here's what the 2024 Tacoma owners manual say about fuel grade / octane:

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 knock-ing. Persistent knocking can lead to engine damage.

Source:

Tacoma owners Manual (Gas / non-Hybrid)
Tacoma owners Manual (Hybrid)

Gas engine (2024 Tacoma):

Hybrid engine (2024 Tacoma):

 

[AZTrail]

Here is a detailed explanation on why high compression turbo engines should not use 85 octane gas even at high elevations: