What kind of gas you feeding your 3rd gen taco

Sorry, not true all the time. Some engines (typically with low compression ratio or using very high octane) will not knock before reaching "optimal performance". Instead the engine will loses torque with advanced timing because the compression stroke tries to push the crank "backwards". I would agree that typically a modern engine will knock before MBT (mean best torque - google it) is reached.

 

Ok. But explain this. How does advancing the timing push the crank backwards? Retarding the timing yes because ignition happens earlier in the compression stroke.

 

Can I run 95 Unleaded in my Taco? It's only $4 a gallon here in North Scottsdale. How about 100 Low Lead aviation gas? lol

 

Ak-Chin Regional Airport in Maricopa, AZ has 100LL for $3.98/gallon. Wonder how the ol' Taco will run with a tank full....

http://www.airnav.com/airport/A39

 

Obviously your truck will go as fast as an airplane. Cause of science and stuff.

 

youre thinking of it backwards.. advanced timing = ignition earlier in compression stroke. retarded timing = ignition later in compression stroke

 

My Taco begs to differ. If it's cold and I have 87 in the tank, I get around 16.5 mpg on the highway. It goes up to 19 with 93. At 50 degrees, the difference is 18 with 87 and 19 with 93. Same trips, same speed, same load, etc.

 

Agreed. Once in a great while, I have to buy ethanol in the city in which I work. Truck mpg goes from 19 to 15. That stuff is horrible and is just another way to fund corn subsidies.

 

I must've missed something. When I use ethanol, the mpg drops considerably. My 16-19 comparison is for regular gasoline without ethanol. The way the dead dinosaurs intended it to be.

 

Damn I am. I got all confused. I had it all backwards my bad.

Ok so I understand now. The engine retards the timing so knock doesn't occur, so the ignition isn't happening to early and the flame front is expanding and pushing the piston down while it's trying to come up. This is knock. The engine needs to retard timing to eliminate knock. The higher octane fuel allows the engine to advance its timing so it can reach optimal timing.

The questions is, does the recommends fuel octane rating aloe the engine to advance its timing for optimal performance? If it does,there is no reason to go any higher, correct?

 

I think we're miscommunicating. Let me try this:

87 octane without ethanol: I get 16.5 mpg on the highway.

93 octane without ethanol: I get 19 mpg on the highway.

87 octane with ethanol: I get 15 mpg on the highway.

93 octane with ethanol: I get 16 mpg on the highway.

So, in my experience with the 2016 Tacoma, mpg is impacted both by ethanol and octane. I have 8300 miles on the odometer at this point and have been paying close attention to the mpg/tank numbers.

Without ethanol, octane seems to make a pretty big difference. With ethanol, I'm just helping farmers continue to grow a crop that no one wants.

 

That's precisely why I try not to buy ethanol-tainted gas. I live in a county with no ethanol requirement and work in a county with mandatory ethanol. I've tried every combination. If you live in an ethanol-mandatory jurisdiction, I wouldn't spend the money on octane. The few times I've had to buy an ethanol-bastardized version of fuel, I just get the cheap stuff (87) after seeing no decent impact on mpg with 93 octane. When I can tank up at home, I get the better stuff for the 2.5 mpg. I haven't worked out the math on cost-effectiveness, but I like seeing 19 mpg vs. 16.5 mpg. With 8300 miles on the odo, 2.5 extra miles for every gallon works out to be a whole lot of extra miles driven between fill-ups.

 

My observed increases in mpg and engine feel have been with ethanol fuel (up to 10%) just different octane. So I would think with the 3rd gen with its relatively high compression, octane has an effect on performance. Sure its safe to run it with 87, but is it "optimal?"

Not sure what the compression difference is between the 2nd gen and the 3rd gen. Perhaps the variances in timing is more pronounced in the 3rd gen, giving it's smaller displacement, but similar power output of the 4.0.

Either way, gas is cheap right now, so I can afford to ball out a little and run mid. Plus with the 3rd gen's wonky shift points, any perceived increase in responsiveness is always welcomed.

 

So I've been running mid-grade on my Taco since I picked up at the dealer. In SoCal, most mid-grades are rated at 89 octane with 87 and 91 being the low and high. So far the Taco has run great with 89 octane.

With mainly city driving (commuting between work and home 10miles each way)
Average range has been between 280-290 miles.
Average MPG according to the dash has been between 15.4-15.8 MPG

On a few occasion I did a few 20-40mile runs on the highway with cruise control and the dash showed between Avg. 18-22mpg.

What has been strange to me is during my city commutes, I don't drive hard and the Avg. MPG readout has always stayed under 16mpg and never fluctuating that much. I tend to ignore it because I know its an Average MPG and not current.

Here is where my story gets weird....

I have just over 2100 miles on the odometer. Just now I went to fill up with the dash saying I had 12miles range left.

I accidentally hit 91 octane at the pump and I didn't feel like starting it over, so I said fuk it, I'll just pump 91 this time.

Topped off the tank with 91 octane for the first time. As soon as I pull out of the gas station the Avg. MPG jumped from 15.8 or so, to 18, then to 20 as I pulled away. A few times I hit 21 and 22 on the street. I wasn't driving any differently than before.

For some strange reason the Avg MPG reading seemed to have woken up and updated more frequently as I accelerated and decelerated. Almost as if it was giving me real time updates.

I haven't seen or heard of this before. What makes this weird is the timing.

I know whatever fuel the engine was getting was not pure 91 since the fuel lines still had 89 in them. If anything it was getting a blend of 89 and 91 octane.

Why did the Avg. MPG reading become more active after filling the tank with 91 octane? Has anyone experienced this?

 

I just realized a few days ago that i have been running 86, im in texas and i dont subscribe to the octane debate. I did fill my last tank with 88. But my mileage has been exceptional with 86 so far

 

You figure the 0% ethanol increases performance? I have a friend that services tractors and chainsaws as well as other small motors. Ethanol really screws things up. Someone needs to compile a list of ethanol free gas stations...

I'm not sure if I've been putting ethanol free in my tank. Should Say on the pump no?

Also I don't necessarily believe higher octane improves mileage. Maybe performance but not mileage by itself

 

Probably a lack of ethanol in the fuel? Confirm this and I think we have a winner

 

I'm not a mechanic, nor do I claim that I know what I'm talking about but this makes sense

 

I can't believe people still are asking this. Isn't this common knowledge now?
Seen multiple horsepower runs with motorcycles... and cars and there was an average of about a 1.5% loss going from regular to super unleaded in a car that takes regular.
Regular unleaded every time. You're not "treating" your truck or cleaning the fuel system with higher octane. Most likely you're very slightly lowering the HP and mpgs.
Just use quality gas (chevron, Shell, etc) and you'll be fine.

 

I was filling up not long ago at a pretty big, fairly new Shell station. I had always stopped at "top tier" stations thinking it must be better. As I was fueling a tanker pulled in, and before I left I struck up a conversation with the driver. I was asking him about the gas, top tier, and where he filled up his truck. He told me that all the trucks fill their tankers from the same depot. He also confirmed that he delivers the same gas to Shell that he takes to "non-top tier" stations on his route including mom-pop and others. So......the same top tier gas I was paying 5 cents per gallon more for could be bought down the street at a station not listed at top tier.