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

[Cajun]

Would like to see E85 results

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[Voodoo Rufus]

I could believe 20HP if the ECU adds a little boost or timing depending on knock detection. If true, it's a nice HP increase. I'm more likely to spend on 91oct because the engine is turbocharged anyway.

I saw another video from Stillen I think on them testing an air intake on the Tacoma iForce engine and getting 20-25HP out of it. I have a harder time believing that Toyota left that much performance on the table just for keeping out dirt and water.

 

[Dead Horse]

Would like to see E85 results

If Toyota would unlock their ECM so tuners could get a handle on it, going cornfed on a forced induction engine is definitely The Way.

 

[ItsmeAlex]

Now that we have lots of actual owners, does anyone run 93 octane and noticed a clear power gain using your butt dyno?

 

[Gastan]

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.​

Someone needs to do this test on the hybrid iForce MAX engine as well.

 

[4runner4]

Now that we have lots of actual owners, does anyone run 93 octane and noticed a clear power gain using your butt dyno?

Put in a 93 tank of gas Exxon and … not really but I’m also not getting on it yet as it’s still under 1k miles.

 

[AtomicSushi]

Because of knock sensors, any modern engine can run 87 octane regardless of what the manufacturer specifies. The ECU responds by retarding the timing and knock is no longer an issue. Is it a good idea in the long run? Probably not. Is it a good idea in the short run? Hell no! I want my engine to make as much power as it can (Within realistic reason) and with high compression engines, you simply accept that higher octane fuels are more appropriate. I only run premium in my vehicles and ethanol free where I can get it.

My 4Runner gets 91 Octane ethanol free from QT cause it's right down the road. My GT 350 gets 93 Octane from whatever gas station runs a Top Tier detergent package because it can handle nasty corn alcohol and I want the highest octane possible.

I do however disagree with the idea of 87 octane being somehow inferior. It is more combustible than higher octanes and it's what is best for most engines. I don't think it will hurt the iForce Max. But, if I am wrong, paying a little more, getting more HP, and having peace of mind is worth the cost of admission.

I haven't seen 85 or 86 octane in years and I go all over the country. I can only assume the reason these states carry it is to make our politicians rich, because that (and not science) govern available octane and ethanol percentages from state to state. Feel free to prove me wrong.

 

[AtomicSushi]

Good points. They did it the lazy way. They need to burn at least 1.5 tankful's to purge the lower octane and produce more accurate results. Hopefully they or someone else will do a test using stricter testing procedures.

Butt dyno is useless for gains below 30 RWHP. I run 91 usually but have had the vehicle less than 2 weeks. As this is a 4Runner, I have no interest wasting my time or money on a real dyno. Let the YouTubers handle that silliness.

 

[AZTrail]

Because of knock sensors, any modern engine can run 87 octane regardless of what the manufacturer specifies. The ECU responds by retarding the timing and knock is no longer an issue. Is it a good idea in the long run? Probably not. Is it a good idea in the short run? Hell no! I want my engine to make as much power as it can (Within realistic reason) and with high compression engines, you simply accept that higher octane fuels are more appropriate. I only run premium in my vehicles and ethanol free where I can get it.

My 4Runner gets 91 Octane ethanol free from QT cause it's right down the road. My GT 350 gets 93 Octane from whatever gas station runs a Top Tier detergent package because it can handle nasty corn alcohol and I want the highest octane possible.

I do however disagree with the idea of 87 octane being somehow inferior. It is more combustible than higher octanes and it's what is best for most engines. I don't think it will hurt the iForce Max. But, if I am wrong, paying a little more, getting more HP, and having peace of mind is worth the cost of admission.

I haven't seen 85 or 86 octane in years and I go all over the country. I can only assume the reason these states carry it is to make our politicians rich, because that (and not science) govern available octane and ethanol percentages from state to state. Feel free to prove me wrong.

85 octane gas is very common in cities at elevations above 5,000 feet.

 

[outdoorCO]

I have ran 85 in non turbo engines for 30 years in CO with no known issues. Plenty of power at elevation.

 

[LARIN]

FYI ,These are not high compression engines, 20 hp gains are with performance tuning and 91-93 octane gas. Most people will only keep these 4Runners 3 to 4 years so if you want premium gas go for it that is your money

 

[The_Dark_Knight_Forever]

FYI ,These are not high compression engines, 20 hp gains are with performance tuning and 91-93 octane gas. Most people will only keep these 4Runners 3 to 4 years so if you want premium gas go for it that is your money

Do you think there is any longevity benefits for the engine general or at least the turbos themselves by running midgrade (89) gasoline instead of regular grade (87)?

I'm not concerned too much with improving performance or power. I just want to put in what I can to prolong the service life of the engine & turbos as well as avoid the need for expensive repairs.

 

[AtomicSushi]

Do you think there is any longevity benefits for the engine general or at least the turbos themselves by running midgrade (89) gasoline instead of regular grade (87)?

I'm not concerned too much with improving performance or power. I just want to put in what I can to prolong the service life of the engine & turbos as well as avoid the need for expensive repairs.

I don't think the grade you run has an effect on long term durability so much as where you buy your gas. The additive packages are what is important. You want to use "Top Tier" gasolines, from Shell, Exxon Mobil, Texaco, QT etc.

@LARIN I was unaware people only keep the vehicles a few years. I usually keep a vehicle 10 years or more. Also, you don't think 11:1 is a relatively high compression ratio?

 

[LARIN]

Yes, if you only shop for a car every ten years you are in the minority, allot of people leased the old 4Runners, or traded them early due to high resale. On newer engines with direct fuel injection, port injection, 11.1 is really not that high, It is high when compared to old carburetor engines or early fuel injection motors and they did require premium,

 

[The_Dark_Knight_Forever]

I don't think the grade you run has an effect on long term durability so much as where you buy your gas. The additive packages are what is important. You want to use "Top Tier" gasolines, from Shell, Exxon Mobil, Texaco, QT etc.

@LARIN I was unaware people only keep the vehicles a few years. I usually keep a vehicle 10 years or more. Also, you don't think 11:1 is a relatively high compression ratio?

Yeah I stopped using gasoline from brands-stations that don't sell Top Tier gasoline a while back. In the past I put in non-Top Tier & Top Tier gasoline in my 2003 Tundra & it's still running like a champ with 352,500+ miles on it to date. But I often use Lucas Upper Cylinder & Fuel Injector Cleaner at fill ups & occasionally use a high quality fuel system cleaner also. But now I usually only fill with Shell & Phillips 66 gasoline & use the Lucas & some fuel system cleaner occasionally. In my new 4Runner I'll only be doing the same but I was planning on using midgrade gasoline only or premium if midgrade isn't available when needed.

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