Octane Rating at Elevation

This may be a stupid question, but here it goes anyway. I'm curious what octane rating everyone is running here in Colorado. I know that the manual says 87, which is regular gasoline at sea level, but is mid-grade at elevation in Colorado. I have been struggling to get a reliable answer to this, but I I was told that if you use regular gas at sea level, you should continue to use regular gas at elevation. The reason that the octane level is different at elevation vs. sea level is because the gas burns differently. I was also fairly certain that the sales consultant told me that one of the nice things about the Tacoma was that it runs on regular gasoline, not midgrade or premium. Then when i went to do my first fill up I pulled up to the tank, and low and behold the manual said 87, which is midgrade here. I bought my 3rd gen for the long haul, and I'm planning to get 10-15 years and 200-250k out of the truck, so I want to do what's best. What are your thoughts?

 

85

 

Heard arguments going both ways. You're gonna get a lot of different answers. Probably best to do your own research and make a conclusion based off that. I will tell you that if you have the HPFP squeal it goes away with higher octane gas. I've always used 85 with the only problem being the squeal. I did just switch to higher octane to prepare for the OVTune.

 

I've always run 87 (mid octane) in my vehicles here.

I ran 85 a few times, circa 2000, and got some pinging. So I only use 87. The price difference in filling up a tank is nominal.

 

I've used 85 for a long time. Unless you are getting any knocking or pinging on 85 there's no real reason to run 87 or higher.

 

Its real real simple. There is a lot of RED tape around this subject to take liability off the manufacture.

OCTANE is simply a rep for anti combustion. (keep it un-scientific for most you on here )

More octane, the harder it is to burn..

More Octane = hard to burn, energy spent to make burn / less pwr made & more heat.

Less Octane = Easier to burn, less energy spent, more power.

You want to run the least amount of octane with out knocking/pinging/detonation. (This is called OPTIMUM).

It is said there is more power in more heat, as heat is a energy & no heat wash when cylinder temp is at max, but i'm not a fan of more heat power.

Argue this info all you want, I will not defend this post nor offer any more explanation.

Thanks.

 

Most are perfectly fine running 85 in a stock Tacoma. If you anticipate a trip to lower elevation or a tow up a grade or both fill up w/87. If you get ping/knock/pre detonation in any instance go up one grade next fill-up. Simple as that. Don't overthink it.

 

I ran 87 for the first year of ownership, then switched to 91 for the second. The slightly better mileage and negligible difference in cost for me (historically I only fill up every 3-4 weeks), I stuck with 91 for the most part ever since. For the longest time it was basically an extra 10 cents a gallon to go up one grade in gas. In recent years that has changed, in some cases significantly. There have been times on road trips I've seen it be as much as 80 cents a gallon difference, and when that happens I'll drop a grade or even two. And obviously it depends on where you are. Back east at my parents, the grades are 87, 89, 93. The change in numbers has to do with air density as I understand it, and yes, the same grade with different numbers should perform about the same at a different elevation. Higher elevations have less air density and therefore need the fuel to ignite easier than lower elevations, thus lower octane ratings. My sales guy made a point of talking about how the manual says a research octane of 91, but that doesn't mean 91 on the pump since those are usually the (R+M)/2 numbers, and 87 was fine. Sometimes the pump will have the RON in fine print as well. Every time I've run 85, at least at 'normal' elevations around here, I get shitty performance/mileage.

 

I'm almost positive the 2nd gen engines benefited from higher octane, but were okay to run on 87.

 

I only run Shell 93 in my 2013. I've noticed better performance since switching over a year ago.

 

The lowest one available wherever I'm at.... I've never had a pinging issue

 

To be totally honest, the only real performance difference you'd likely notice is due to weight savings in the wallet. The computer is going to adjust timing, spark... to run what ever it can without knocking. There are more than a few study's out there looking at the difference in fuel grade vs. altitude, and pretty much all of them find no significant difference on modern stock computerized engines. Now if you're tuned to higher compression, force fed in anyway then the outlook definitely changes.

 

So, living at 4,500 ft of elevation I can tell you why 85 octane is all you need, 4,500 feet of elevation. At the higher altitude you have less air pressure which equates to a lower effective compression ratio. The lower the compression ratio, the lower the octane you need to prevent the gas/air mixture from pre-ignition, or pinging. That all there is to it. I've run 85 for decades without a problem in all of my cars. To those that advocate giving the oil companies more money to run higher octanes in vehicles that don't need it, I say a fool and his money are soon parted. I've tried running premium and it made exactly zero difference.

 

I only use 100 octane unicorn blood to feed my beast.

 

Banned!

 

In for the lulz

 

I use 85 in all my older vehicles. E85 in my high performance turbo cars and 87 in the wifes tacoma. Felt a strange pinging hesitation once on a major hill on a mountain pass when running 85. I could literally feel the timing pull from the detonation. Also you cant feel slight detonation. If you hear or feel pinging its causing major damage.

You pretty much want to run the manufacture suggests. They built the tune and motor compression to work best off 87 octane. The least amount of detonation and timing pull the better. Even though the ECU can pull timing to stop detonation you are still damaging the motor every time it detonates. When the motor detonates it eats up piston tops and valves.

 

So connecting the dots in what you're saying... Every time you hear pinging you're eating up pistons & valves. No. That's not how it works.

 

If the motor is detonating. Its very bad. When detonating or pinging or preignition the pistons and valves get eaten up. I have seen this first hand tuning turbo charged motors.

Here is a quick quote I found online that sums it up pretty much.

"Detonation (also called "spark knock") is an erratic form of combustion that can cause head gasket failure as well as other engine damage. Detonation occurs when excessive heat and pressure in the combustion chamber cause the air/fuel mixture to autoignite. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel. When these multiple flames collide, they do so with explosive force that produces a sudden rise in cylinder pressure accompanied by a sharp metallic pinging or knocking noise. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading."

 

110 race fuel gives me like an extra 90whp