What octane are u running ?

So... is 87 non ethanol better than 93 with ethanol for engine? Paying the same price for both so that’s not in the equation for me

 

If I could find ethanol-free 87, I'd try it. I bet it would be as good as premium w/ ethanol. Someone else reported that was his experience earlier in this thread.

 

You have completely missed the point. Balancing air and fuel is what everything does, including (ideally), a carburetor. This has NOTHING to do with octane (combustion inhibition) needs.

The point I made is that the AIR ITSELF is a much lower density. If you have HALF THE MASS of air in the cylinder, then the absolute pressure in the combustion chamber at the top of the compression stroke will be LOWER. Lower pressure means less heat, and less heat means you don't need to inhibit combustion as much -- i.e., lower octane is needed.

 

This is true. I think it's hilarious people still think octane = power. It doesn't. As others have said, all octane does is prohibit predetonation before the spark and its ONLY needed in higher amounts if the compression is high enough to heat the fuel to the point of combustion. THIS IS NOT OUR ENGINES PEOPLE. You will not get a "smoother running engine" using higher octane, you will not get "better gas milage" using higher octane, you will not get "more horsepower" using higher octane. All you're doing is blowing that extra octane right out of the tailpipe.

Its almost 2019 people. Come on.

 

I get better gas mileage, more power and my engine runs smoother on 93 octane. By the way the compression ratio is almost 12:1 on the 3.5, shouldn't be hard to fathom how higher octane helps these engines run better...if you know how all that works.

 

You will actually get a lot of those things because of our engines adjusting the timing. It will advance timing with 93 octane and with lower octane will retard timing if knocking is detected

 

Yes but it is the same amount of power stored in the gas. Timing is only to maximize the compression stroke, not add power. This would in theory minutely increase efficiency however the ECU only adjusts timing IF the engine detects knocking, which it wont because regular 87 is all that is required in these engines to operate at peak efficiency.

You're not getting anything more out of your engine by using a higher octane. You're fooling yourself thinking otherwise.

For the record, with 87 10% ethanol I typically get ~20-21 mpg on my commute (mix of freeway and residential) that's v6 4x4.

 

Carburetors do not automatically adjust for altitude-based leaning, so they're the ideal application for reducing the octane -- not because you have to, but because you CAN get away with it without causing premature detonation. It's a way for the oil companies to sell cheaper fuel (85 octane) for the same price they'd ask at lower altitudes for 87 octane.

I'm not arguing with you about air density relative to altitude -- we're saying the same thing.

 

No one needs to run higher octane unless you're boosting - these trucks have low compression engines. There's a psychological benefit to some - that's about it however.

 

In what world is 11.8:1 a low compression ratio? It's not. The older 4.0L (1GR-FE) was 10.0:1, which was also not what most would consider low compression.

 

I rescind my previous statement been living in the stone ages here working on my truck under a rock







I'd still stick w/ the manufacturer's specified octane rating unless tuning / boosting.

 

If memory serves me the 1st year or 2 of the 2nd Gen Tacoma had a HP rating of 245 and ran on Premium, then they lowered it to 236 HP on 87.

 

Serious question.
Does anybody in this thread actually know how the ecu determines timing advance, or what the base timing map looks like against actual timing while using different octanes? Without answering yes to these questions, you don't possess the knowledge to be answering the op's question. Everyone here is discussing theory and nobody has seen what is actually happening in the ECU. The only person I know of on this forum who could possibly answer this question with evidence to back up the response would be the Orange Virus guy, and he probably wont be seen in this thread.
Now, if you do know, I'm curious to the answer.

 

Just because an engine can run on 87 doesn't mean that it is running at peak efficiency. Do you really think Toyota wants to say the engine has to run on Premium? No because no one would buy it, so they make it where you can run 87 but at the cost of reduced timing when it detects knocking. My question is have you ran 87 and 93 in your Tacoma?

 

Boom! Couldn't have said it better. Just because it CAN use 87 doesn't mean you're getting the most out of these high compression engines. I wouldn't spend the extra coin at the pump if my truck didn't drive worlds better on premium.

 

Well. I recently did a real world test, and I can confidently say I have lost 2 MPG switching from 91/93 down to 89. SO I'm not buying the story that 87 is going to give me the same fuel economy and performance.

That said, 91/93 costs anywhere from 20 to 40 cents more per gallon where I live. So is it worth it? Let's do some math now....

21 gallons times we'll say 30 cents per gal is $6.30. That's the savings for choosing 89, or the additional cost for choosing premium. That's also about the cost of 1.8 gallons of 91/93 octane fuel here. I'm getting about 18 mpg with 91/93.

Now... 21 gallons times 2 MPG is 41 miles of savings from running 91/93 based on the results I'm seeing. 41 miles divided by 18 MPG is 2.27 gallons saved per tank by using 91/93. 2.27 x 3.50 (~ cost of premium per gallon) = 7.94 savings on fill-ups for 91/93 octane, or about 7.25-ish savings if you want to compare to 89 octane. So it seems I'm saving a grand total of about $1 - $1.50 per tank by running higher octane fuel. It runs noticeably smoother, and has a very slight more pickup. Where the noticeable savings comes in for me is when you only need to nurse the pedal to maintain speed instead of having to give it a little more consistently.

 

No. And my point is you dont have to, nor should you.

Here's some quick math, average fuel prices as reported right now from AAA have the difference between premium ($3.03) and regular ($2.44) at $0.59 per gallon. Here is the link: https://gasprices.aaa.com

Traveling 100 miles on 87 assuming 20 MPG (based on my lower average at 20-21 mpg) it will take 5 gallons at a cost of $12.20 for reg.

5 gallons at premium = $15.15 or a difference of $2.95. That is the price of more than one gallon of reg. You're not going to get enough of a return to make it worth it. Basically you'd need to be getting at least 24 mpg to justify the extra cost, which frankly isnt going to happen. This is what people call the placebo effect, any benefit is in your head.

If you listen closely you can hear the dwarfs laughing

 

I'm sorry but no. You're also getting lower gas milage than I am using 87. Could be driving habits? Idk.

 

mmmkay... I guess you're right and you know what real results I got from my recent testing. There is very wide range of gas mileage reported on this site. And I have even achieved up to 22 MPG in the past when reeeeaaalllyyy trying pulling out all the stops including shifting to neutral down hills and taking full advantage of free fall speeds without breaking, etc. etc..

Yes. Driving habits are absolutely a major factor here. And I'll admit that if you run 87 or 89, you can probly acheive a bigger difference i gas mileage simply by changing how you drive, your tolerance for coasting more, and going slower. My test I was sure to drive similarly without trying to save gas by forcing a certain driving behavior. And driving the speeds I typically would drive in whatever speed limts and various conditions. And YES... 2MPG worse mileage with 89.