Hello here is a description of my TE 2011
Mickey Thompson tires Baja ATZ 265-70r17, I don't know the brand of the mags, haven't looked at it to be honest.
KDSS, I have a roof rack Safari that I modified.
The truck has a Grill guard and it has 2 PIAA 6 inch in the front.
It has a hood protector and same thing on the doors.
How many miles do you have on it? 6235 miles.
Where do you live? Montreal, Quebec, Canada.
Where does your relative live? Laval, Quebec, Canada, about 30 minutes from my house.
What mix of driving do you do (%highway to city) 60% city 40%Highway.
What is your relative's mix? Hmm about 60% highway 40city.
What do you haul (like lots of kids, etc) 2 kids and wife.
What does your relative haul? Same 2 kids and wife.
Do you have any aftermarket mods (like a roof rack, etc) Roof rack,big grill guard.
How far do you drive normally? 4 days of work about 10 miles to and back home, the other 3 days about 30 miles a day, shopping and picking up the wife and kids from kindergarten.
Do you let it warm up? Not really, maybe now yes since winter is coming.
Is there a lot of stoplights? Only the 2 PIAA in the front.
But like I said the SR5 does 17.3 mpg in the city and my TE does 16.2 on the highway. That sucks. And when I am on a hill when I step on the gas the truck seems to struggle.
OK, I cannot tell you why your brother in law get better milage than you (without more info on his 4Runner) but I can tell you why you are only getting 16 mpg.
Let's get started:
Tires - You have gone from a stock tire that weighs about 37 lbs to a tire that weighs 51 lbs. That's an increase of 14 lbs each. Yes, you are getting a superior tire that is much tougher with 6 ply but you are paying for that every time you drive. By adding a total of 56 lbs of unsprung weight (weight added below suspension like brakes, tires, wheels, etc) you are taking away almost 1 mpg. How? Every time you step on the gas you have to accelerate the mass of the tires and wheels. Once on the highway it does not affect the efficiency much. The big hit is getting them moving. You gave me a ratio of 60-40 city to highway miles. That means you have driven them 3,741 miles in the city with the start and stop driving that goes with it. Even if you started and stopped only every two miles that is 1,870 starts and stops. This means you have had to accelerate an ADDITIONAL 104,748 lbs just driving in the city by switching to LT tires. Yeah, about an extra 1 mpg efficiency loss there. This does not include the new wheels either.
Driving style:
I know it gets cold in Canada. You drive about 10 miles one way most of the time you drive. You said you normally don't warm up the vehicle, you just get in and go.
Your 4Runner goes through a warm up cycle every time you start it. After temps get to operating parameters the ECU changes engine operating parameters. One of the parameters is fuel mixture. Think of it like a old school choke that runs rich until the engine warms up then you can lean it out as it gets warm. The 4Runner does the same thing in a high tech way. By taking a lot of short trips without any warm up you probably don't get out of warm up mode until you get halfway to work. Same thing happens in the evening. You will use more fuel during this warm up period. With your driving didtance and habits I would say this could cost you around .25 mpg efficiency loss.
Mods:
Other than tires it looks like you have only added a "big" grille guard and a roof rack. You have two things going on there: Added weight and aerodynamic loss and yes, our trucks have aerodynamic design features. The added weight "up top" is not as detrimental as adding unsprung weight but it still costs to carry it around. Let's say your additional components weigh 200 lbs total. That's another .5 mpg or so right there.
I have kids (older now) so I know how much stuff has to go along with having them. Suffice to say a lot lol. I know a 4Runner is a big heavy SUV that has a full frame and all but it is tuned and geared from the factory to get good gas milage. Any changes like you made will result in an efficiency loss. For example, if you had a Chevy Tahoe you might only get 16 mpg from the start. You could add this weight though and still get 16 mpg because of the difference in gearing and tuning. If you re-geared the 4Runner it might drop you down to 18 mpg overall but you could add the weight and not lose any efficiency.
In order to get the mpg as advertised you pretty much have to do it with a bone stock 4Runner. Any changes will result in a loss of efficiency. I said in a previous post that the unmodded guys here all got advertised mpg and we do. I just counted up around 2 mpg loss above and we did not even talk about some of the other losses you might have. So, if you want to leave all the stuff you have on there AND get good gas milage you have to learn to drive it very delicately. Very slow starts, let it warm up for a few minutes even in the summer and so on. Otherwise you will continue to get sub par gas milage. Now if you tell me your brother in law has the exact same mods and gets 1 mpg better then the only thing I can think of is his driving habits and style is much different. Hope this helps.
Although 16.5 MPG is still really bad.
