6th Gen + Snow = Amazing

[mars001]

I suspect that different parts of the U.S. have different low end octane ratings. You are probably just used to seeing 87 octane in your area.

Thanks. Must be so. I'm in CA but did travel to neighboring states. I remember even seeing 100 octane in some stations in Nevada.

 

[JIMIPRO]

Colorado ratings are 85/87/89. 85 is perfectly fine here.


Why does Colorado have lower octane gas?


AI Overview
Colorado, along with other states in the Rocky Mountain region, uses 85-octane gasoline as the "regular" grade due to the lower air density at higher altitudes, which reduces the risk of engine knocking compared to lower elevations where 87-octane is standard.

Here's a more detailed explanation:

• Altitude and Air Density:
  At higher altitudes, the air is less dense, meaning there's less oxygen available for combustion.
  
  
• Engine Knock:
  Engine knocking occurs when the fuel ignites prematurely or too quickly, causing a knocking sound and potentially damaging the engine.
  
  
• 85 Octane as a Solution:
  In these high-altitude areas, 85-octane gasoline is used because it's less prone to premature ignition compared to 87-octane gasoline at sea level.
  
  
• Other States:
  Besides Colorado, states like Utah, Wyoming, Idaho, Montana, and New Mexico also use 85-octane as the regular grade in areas with high elevations.
  
  
• Carburetion Era:
  The use of 85-octane fuel in these areas dates back to the era of carbureted engines, where 85 octane was a common base grade.

 

[kzrman]

Thanks. Must be so. I'm in CA but did travel to neighboring states. I remember even seeing 100 octane in some stations in Nevada.

Must be for those people taking the high speed runs out in the Mojave desert.

 

[willb]

To make a point, you shouldn't be using 85 octane in turbo charged cars at altitude.

It's fine if you're running around town doing 2-3k rpm tops, but up in the mountains under load you can suffer some serious engine problems.



I'm planning on using 89 or 91 octane exclusively.

Is stick with what the gas cap states

 

[kzrman]

Colorado ratings are 85/87/89. 85 is perfectly fine here.


Why does Colorado have lower octane gas?


AI Overview
Colorado, along with other states in the Rocky Mountain region, uses 85-octane gasoline as the "regular" grade due to the lower air density at higher altitudes, which reduces the risk of engine knocking compared to lower elevations where 87-octane is standard.

Here's a more detailed explanation:

• Altitude and Air Density:
  At higher altitudes, the air is less dense, meaning there's less oxygen available for combustion.
  
  
• Engine Knock:
  Engine knocking occurs when the fuel ignites prematurely or too quickly, causing a knocking sound and potentially damaging the engine.
  
  
• 85 Octane as a Solution:
  In these high-altitude areas, 85-octane gasoline is used because it's less prone to premature ignition compared to 87-octane gasoline at sea level.
  
  
• Other States:
  Besides Colorado, states like Utah, Wyoming, Idaho, Montana, and New Mexico also use 85-octane as the regular grade in areas with high elevations.
  
  
• Carburetion Era:
  The use of 85-octane fuel in these areas dates back to the era of carbureted engines, where 85 octane was a common base grade.

Thank you for the nice explanation. I still wonder whether the ECU on modern vehicles can change the timing enough that you don't half to worry as much about the fuel being used.

 

[CO/ZA]

Colorado ratings are 85/87/89. 85 is perfectly fine here.


Why does Colorado have lower octane gas?


AI Overview
Colorado, along with other states in the Rocky Mountain region, uses 85-octane gasoline as the "regular" grade due to the lower air density at higher altitudes, which reduces the risk of engine knocking compared to lower elevations where 87-octane is standard.

Here's a more detailed explanation:

• Altitude and Air Density:
  At higher altitudes, the air is less dense, meaning there's less oxygen available for combustion.
  
  
• Engine Knock:
  Engine knocking occurs when the fuel ignites prematurely or too quickly, causing a knocking sound and potentially damaging the engine.
  
  
• 85 Octane as a Solution:
  In these high-altitude areas, 85-octane gasoline is used because it's less prone to premature ignition compared to 87-octane gasoline at sea level.
  
  
• Other States:
  Besides Colorado, states like Utah, Wyoming, Idaho, Montana, and New Mexico also use 85-octane as the regular grade in areas with high elevations.
  
  
• Carburetion Era:
  The use of 85-octane fuel in these areas dates back to the era of carbureted engines, where 85 octane was a common base grade.

Sure, like the video says.

Not a problem in day to day traffic in Denver when you're barely putting load on the engine while commuting.

But putting 90 - 100% load at altitude in a turbo car may cause problems.

Owners manual says minimum 87 octane, regardless of what the fuel cap says.

Toyota can and will void your warranty should you cause a problem, if they wanted to - just like Ford explicitly will if you're putting 85 octane in your 3.5 Ecoboost.

85 octane has no place in a modern vehicle, it's a cheat devised in the 1960s - as your AI synopsis states.

Running 91 octane in a 2.4 Toyota turbo gets you an extra 20hp in any case:

 

[CShel]

I heard that the new 4 runners require premium fuel as stated in the owners manual and it is quite a bit more expensive where I live, but also living in the mountains I was always told this: Due to lower air density at altitude the running compression ratio is lower than the mechanical ratio and lower octane is sufficient to prevent detonation so 85, 87 and 89 octanes at several thousand feet do equate to 87, 89 and 91 at sea level.

 

[LLL1990]

3. Is the traction control system active while in 4hi and/or in all modes - The only time I believe it disables and have seen it disabled is 4L. Otherwise it's on, i've only noticed it kick in when getting heavy on the pedal going over a steeper grade in snow w/o using 4H

In this generation when you're in 4L traction control isn't disabled it's in A-Trac (Active Traction Control). On the previous generation you had to press a button to turn it on but in this generation Toyota programmed it be active anytime you're in 4L. What is disabled in 4L is the stability control system.

 

[willb]

I heard that the new 4 runners require premium fuel as stated in the owners manual and it is quite a bit more expensive where I live, but also living in the mountains I was always told this: Due to lower air density at altitude the running compression ratio is lower than the mechanical ratio and lower octane is sufficient to prevent detonation so 85, 87 and 89 octanes at several thousand feet do equate to 87, 89 and 91 at sea level.

I'm curious where the manual states that it requires premium fuel?

 

[AZTrail]

1. Are you shifting on the fly from 2wd to 4hi on pavement in mixed snow conditions smoothly and at what speeds - I would swtich to 4H on the fly while driving at speed, and back to 2 with no issues

The 2025 4Runner Owner's Manual states that you should only shift between 2H to 4H or 4H to 2H when your speed is less than 62 mph.

 

[AZTrail]

What tires did you have? Were they 4 peak snow rated? Most of the tires Toyota puts on the new 4Runner are not snow rated and Toyota also says you can't put snow chains on tire size 265/70R18 which is the standard size for the OR and ORP.

 

[LLL1990]

What tires did you have? Were they 4 peak snow rated? Most of the tires Toyota puts on the new 4Runner are not snow rated and Toyota also says you can't put snow chains on tire size 265/70R18 which is the standard size for the OR and ORP.

I think his experience shows how good Toyota has programmed the traction control system on the 6th gen. Even without tires rated for snow it gets through without breaking a sweat.

 

[willb]

The 2025 4Runner Owner's Manual states that you should only shift between 2H to 4H or 4H to 2H when your speed is less than 62 mph.

Yeah, and I can't see a case where someone would be doing over 60 and need 4x4 so a non-issue for me.

 

[willb]

I think his experience shows how good Toyota has programmed the traction control system on the 6th gen. Even without tires rated for snow it gets through without breaking a sweat.

Exactly my point, it was flawless effort with very variable conditions. Impressed for sure

 

[willb]

What tires did you have? Were they 4 peak snow rated? Most of the tires Toyota puts on the new 4Runner are not snow rated and Toyota also says you can't put snow chains on tire size 265/70R18 which is the standard size for the OR and ORP.

Yeah I would never even consider needing or putting on snow chains.