What am I not understanding about MPGs ?

[FlyAngler]

How are you calculating your mileage? If your speedometer is off because of the larger tires, then your odometer will be too. Gotta factor that in... If your tires have a larger diameter than stock.

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[PNWkip]

How are you calculating your mileage? If your speedometer is off because of the larger tires, then your odometer will be too. Gotta factor that in... If your tires have a larger diameter than stock.

I do need to hand calculate to get accurate overall mileage and look into recalibrating , but as the original post says, I was just asking why the computer shows 14+ driving around town like a grandma all week and 16+ driving around like an asshole. Doesn't make sense to me.

 

[Ironhide]

How are you calculating your mileage? If your speedometer is off because of the larger tires, then your odometer will be too. Gotta factor that in... If your tires have a larger diameter than stock.

You’re 100% right. Everything is out of wack with anything other than the OE size. The average mpg is just an estimate anyway. More like a shameful reminder of what my mileage could have been before the upgrades. Just using a rough 2-8 mph addition to what the speedometer reads. If it reads 50, Im actually doing about 54. 60, I’m going about 65. And 65, I’m probably knocking on 72.

 

[PNWkip]

You’re 100% right. Everything is out of wack with anything other than the OE size. The average mpg is just an estimate anyway. More like a shameful reminder of what my mileage could have been before the upgrades. Just using a rough 2-8 mph addition to what the speedometer reads. If it reads 50, Im actually doing about 54. 60, I’m going about 65. And 65, I’m probably knocking on 72.

I hear what you guys are saying, but I just feel there shouldn't be an increase in estimated MPG with an increase in aggressive driving. If everything is equal, conservative driving should net better fuel economy. That's always been my thought anyways.

Right before this I had an old v8 f150 for 6 months or so, but before that I had an EV for almost 2 years. I got in the habit of driving gingerly to increase range which, comically, was more than my Tacoma. It doesn't seem that the same principles apply to my Taco.

 

[nickd]

I think you need more data with both tires sizes before analysis.

 

[Ironhide]

I do need to hand calculate to get accurate overall mileage and look into recalibrating , but as the original post says, I was just asking why the computer shows 14+ driving around town like a grandma all week and 16+ driving around like an asshole. Doesn't make sense to me.

Do you think resetting the average mpg from a stop with o zero mpg, vs rolling with a 19mpg, could play a significant part in factoring the average? Or even factoring in remote starts, sitting at idle for however long?

 

[PNWkip]

Do you think resetting the average mpg from a stop with o zero mpg, vs rolling with a 19mpg, could play a significant part in factoring the average? Or even factoring in remote starts, sitting at idle for however long?

Remote starts are a good point! They can vary in length.

Ok. Here is exactly what I did and why I'm asking:

Fill the Tank. Reset the computer. Drive like a Grandma all week. 14 ish MPG.

Fill the tank. Reset the computer. Drive like a 19 year old with a WRX named Kyle. 16+ MPG.

All computer estimates.

I think ultimately what I'm going to do is forget about this and just continue going to the gas station more often than I used to go to the charging station. Taco life

 

[Ironhide]

Remote starts are a good point! They can vary in length.

Ok. Here is exactly what I did and why I'm asking:

Fill the Tank. Reset the computer. Drive like a Grandma all week. 14 ish MPG.

Fill the tank. Reset the computer. Drive like a 19 year old with a WRX named Kyle. 16+ MPG.

All computer estimates.

I think ultimately what I'm going to do is forget about this and just continue going to the gas station more often than I used to go to the charging station. Taco life

Last thoughts on this. Perhaps the truck had allergies or was self-adjusting for mixed fuel or the added weight of the tires. But like @nickd said, “…need more data”.

 

[RUBICONXJ]

I can't get my average above 13.9. Other than the 5 hour trip driving it home, it's mostly a 2 mile commute to work. With the factory lift and larger tires, I never expected to get the EPA rating, but this is ridiculous.
I've had multiple Toyotas both with the 4.0 and 3.5 and they took 5-10k miles to break in and get better gas mileage.

I'm about to do the first oil change at 2k and see if that improves. I'm just afraid the mileage won't be realized on short commutes regardless.

What do I need to do to reset the mpg history? And is that even accurate?

 

[PNWkip]

I can't get my average above 13.9. Other than the 5 hour trip driving it home, it's mostly a 2 mile commute to work. With the factory lift and larger tires, I never expected to get the EPA rating, but this is ridiculous.
I've had multiple Toyotas both with the 4.0 and 3.5 and they took 5-10k miles to break in and get better gas mileage.

I'm about to do the first oil change at 2k and see if that improves. I'm just afraid the mileage won't be realized on short commutes regardless.

What do I need to do to reset the mpg history? And is that even accurate?

I'm kind experiencing the same thing. I've put 3,500 miles on mine. It had 4k when I got it and was all stock with 245s. I've made a couple switches between 265 & 275 for some tire warranty stuff, but most recently 275/70R18 and I'm getting shitty mpg in town. My original question about spirited driving aside, even if I hand calculated it, it's about as good as my 2006 V8 Triton with a 6 inch lift and 35s.
I'm not mad, but definitely did not expect my '25 Taco to get the same MPG as this 20 year old bro dozer:

 

[MJB4450]

I’m not buying the study. Michu Kaku: takes the same amount of energy to cover that distance in the exact same amount of time. The variable is air resistance, if the engine is to temp, time (perceived faster but in reality took longer), braking, etc

Albert Einstein is rolling in his grave. From a complete stop to crossing the end point at the exact same elapsed time, explain how the laws of physics can be defied & you get free gas by goosing it off the line vs driving like grandma.

I imagine it would have to do with the efficiency of the engine under various loads vs time. Yes, you're using more fuel when accelerating quickly but accelerating slowly for a much longer period may not be as efficient as quickly for a short time. An example would be that V8 engines are far more efficient than a 4 cyl when you measure mpg vs hp. A 400 hp V8 may get 20 mpg while a 4 cyl engine half the size would not get 40 mpg, more like 30 mpg. So in this example the V8 is 50% more efficient than the 4 cyl. when comparing cubic inch or hp. vs mpg.

 

[trailhunger]

I imagine it would have to do with the efficiency of the engine under various loads vs time. Yes, you're using more fuel when accelerating quickly but accelerating slowly for a much longer period may not be as efficient as quickly for a short time. An example would be that V8 engines are far more efficient than a 4 cyl when you measure mpg vs hp. A 400 hp V8 may get 20 mpg while a 4 cyl engine half the size would not get 40 mpg, more like 30 mpg. So in this example the V8 is 50% more efficient than the 4 cyl. when comparing cubic inch or hp. vs mpg.

I stand corrected. After some deeper digging yes efficiency (internal friction) of the how the ICE behaves during acceleration can in fact affect MPGs

 

[Wife bought my 24 TRD]

I know why I get 14mpg, adding weight, lifting it and changing the aerodynamics of the front of the truck, leeds to S*** for mileage not rocket Science. I dident by mine to be a daily driver, I bought mine to build a toy. As they say, it is what it is.

 

[PNWkip]

I stand corrected. After some deeper digging yes efficiency (internal friction) of the how the ICE behaves during acceleration can in fact affect MPGs

I'm glad someone has brains out there. Because I'm just like "why cheese yellow"

Thanks guys ! This was a great discussion.

 

[izzy]

Turbo engines are very two faced. That said, a turbo engine is using more fuel while in boost than not, even if you're higher up in the RPMs. MPG is almost always tied to load and not RPM. That's why a D15 in a 95 Honda Civic gets 45MPG at 65 at 4000RPM.

There's a pretty consistent 30 mile freeway drive I do, and I experimented with doing it in 7th vs 8th. I found that in 7th, when going up the small grade this drive has, the truck was actually not in boost at all. It was utilizing it's horsepower more than it's torque. When you need torque from a turbo 4 banger like this you're in boost, and thus, getting probably like 5MPG real-time.

If you accelerate slowly, or worse, allow the truck to shift to 3rd and then roll on the throttle, you're going to use more gas than 50% requested power acceleration for sure. Cause instead of shifting to 4th the truck will sit there in 3rd and build boost, thus rip MPG.

In all honesty the gearing is so long in these trucks in the bottom 3 gears it's kinda crazy. I'm guessing they did that because consumers would probably whine if the heard their 4 banger truck make 4 banger noises...lol

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