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Improving Gas Mileage

151K views 187 replies 123 participants last post by  hotrodjoe1 
#1 ·
i have 2012 FJ i would to improve my gas mileage along with performance, what are my options? Thanks
 
#2 ·
buying a prius ... :)

there are no add-ons to increase mpg or performance. mostly we lose mpg due to bigger tires and lifts once you start modding.
 
#3 ·
Don't believe what they tell you about not improving fuel efficiency.

The following will improve performance and MPG.
1 - Switch to a quality electric fan
2 - Lightweight FlyWheel if you have a manual
3 - Lightweight forged aluminum Rims.
4 - LT - HWY tires on those lightweight rims.
5 - CF or Aluminum Drive shaft


Keep your heavy stock rims loaded up with some good AT/MT tires for offroading and your DD tires on the aluminum street rims.

Rotating mass is the killer of Fuel efficiency and power. By reducing that you will notice significant gains.
 
#5 ·
Bullies :stickpoke::lol:

I say the cheapest mod for better gas mileage is ScanGaugeII or similar, it will tell you what you are doing wrong. As far as performance, the only proven one is supercharger, everything else is not substantial :) Supercharger is not avail for 2010 and up...yet.
 
#69 ·
x2 re ScanGaugeII ... its helped me change my driving habits ... :cheers:
 
#6 ·
Drive as though you have Miss Daisy next to you. Seriously, I started out getting 24MPG HWY/Logging road combined. Then, I realized how much fun it was to drive the FJ fast down gravel/dirt logging roads, passing on the HWY...Now I'm averaging 21MPG on the same trip. Maybe I need to get a scanguage so that I have an in-your-face reminder.
 
#7 ·
Bone stock except rack and rails. Baby the throttle and you can see 24. I have 29000 and just got a hair over 24 on my last tank.

If you do things to improve performance, chances are you'll have trouble keeping your foot off the throttle, and mpg will suffer.
 
#12 ·
Great link. I thought it was a government mandate that all gas in USA contains ethanol. problem is that it's 60 miles round trip from my location to get Ethanol free at one of Tge 4 gas stations in UT that sell it:(
 
#17 ·
On the highway keep it at or below 2000 rpm. The more mods, like lifts and bigger tires, the lower your mileage. Forget tricks like cold air intakes, etc. If that stuff was worth while, Toyota would have done it. Mine is an 07 and runs fine on regular. It may help a little but I've always used Mobil 1 synthetic engine oil........I always use Mobil 1 as a gun lube as well. :cheers:
 
#19 · (Edited)
Does running Mobil 1 synthetic engine oil help with gas mileage (cooler engine temp.) I always ran regular oil but switching on my next change.

Like other has always said, you're driving the wrong type of vehicle is gas mileage is a major concern. I have it all (lift, tires, winch, etc.). I love my truck and the way it looks and drives. You get to the point that you swipe the card and pump the gas until it's full and just drive and enjoy the truck. Some days you drive nice and light/easy other days I'm faster to enjoy the sounds and minor gains from mods (it sounds faster).

Not saying one shouldn't buy a FJ and expect ok mileage. Just leave it stock with no roof rack. Level it for looks and drive like a old lady...:wave:
 
#21 ·
Hello everyone..... Former Rock Warrior owner converted to 2013 FJ, Trail Teams
That being said
I totally get the reference to aerodynamics and general or stock performance......
But some guys on here are stating 24-MPG........I am consistently looking at a solid 18!!!
I'm bone stock as far as the 2013 TRD edition but, mine came with the crawler package. Is this why my mileage is much less than other guys????
Again, new with FJ. So I'm used to about 21-MPG with my Tundra at a curb weight of 7200.
Really don't need any smart remarks about, then you should have kept your truck and so on. Any REAL knowledge would be great.
 
#22 ·
Funny, I was considering a '09-'10 Tundra but went with the FJC because of mileage, lol. I have a stock '08 4x4 5AT with +70k miles on it now and I get +/-18mpg driving it however I want to during the daily commute (24mi one-way, combined Highway & Stop-and-Go traffic). If I was more easy on the throttle on acceleration and stuck to <70mph in the right lane I'm sure I could see low-20's on a tankful, but my right foot is not built that way and the left lane is my adopted home.

My issue with regards to the FJ's fuel consumption isn't so much the rate at which it drinks gas, but that the fuel tank is only 19gal. I mean, we all should have known what we were getting into MPG-wise when we bought an FJ... It's not a Highlander, but it's also not a Tundra, right? Still, I'd be willing to bet that 17-18mpg would be slightly less of a deal to anyone if the tank was big enough to net a 400mi range straight from the factory.

In my experience your combined MPG is normal for stock FJs that are just driven normally. By that I mean those that are not driven full-throttle away from every stop, nor are they driven with one eye on the tachometer or ScanGauge. :cheers:
 
#23 ·
Hey thanks for the return message.... Been checking on a response every couple days. I know this is an old topic to FJ Vetrans but being new, I think it's the basics that you hunger for in order to outline you capabilities. That being said...... I went on a trip to AZ this last weekend and kept my FJ at 70 religiously!!!! I did not know the tank size, but the gas light went on and stayed for what I thought was well long enough. I noticed at 70MPH the first Quarter Tank took me to 113 miles and from there the second Quarter Tank took me only 57 miles. So at the Half Marker I had traveled 170 miles. Did not follow it the rest of the way but, my trip counter had me at exactly 303 mile and was showing E. So I get out and proceed to empty all 3 of my 5 gallon Jerry Cans. This fill the FJ completely and I had about 6 ounces or so overflow. So I know now that I had almost perfectly used 15 Gallons of the 19 and had just a tiny bit over 4 Gallons before I filled it back up. My point is I know I traveled 303 miles on 15 gallons at 70-MPH which should equal 20.2-MPG. And also shows that the Gas Gage is poorly designed and or engineered because my FJ showed E and the light was on but according to my calculations I still had 4 Gallons to go and quite possibly another 80 miles..............
 
#106 ·
And also shows that the Gas Gage is poorly designed and or engineered because my FJ showed E and the light was on but according to my calculations I still had 4 Gallons to go and quite possibly another 80 miles..............
Sorry for quoting an old post...but there's a psychology to the way a gas gauge reads. This old Motor Trend article should be required reading for all gear heads. Little White Lies From Your Dashboard;

Technologue - Fuel Starvation - Motor Trend Magazine
 
#24 ·
My point is I know I traveled 303 miles on 15 gallons at 70-MPH which should equal 20.2-MPG. And also shows that the Gas Gage is poorly designed and or engineered because my FJ showed E and the light was on but according to my calculations I still had 4 Gallons to go and quite possibly another 80 miles..............[/QUOTE said:
Those are all good numbers from the figuring I've done on my 2012, and being that the FJ can get you lost in the hills an 80 mile reserve is a good thing! :bigthumb:
 
#26 · (Edited)
I checked my gas mileage many times with Scangauge 2

It depends on speed

50 MPH - 20-21 MPG
60 MPH - 17-18 MPG
70 MPH - 15-16 MPG

The best MPG I am getting at 45-50 MPH (RPM about 1200) , about 21-22
Cruise control is OK, but not the best choice for mileage, I was using MPG gauge on SG-2

I have 2008 AT, 285-75-16 KM-2 tires, 3" lift, some heavy tools in the back,
AFE intake and MBRP cutback, URD corrector for it.

I found that new intake and exhaust give me about 5-7 % fuel economy (1-2 mpg)

I am measuring mpg almost everyday on the way back from work at 3AM in the morning with no traffic...

3 years ago stock FJ at speed 50-55 highway was about 24 mpg
 
#27 ·
I've read that AMSOIL oil can help with getting better fuel economy. Any anecdotal evidence of that? I'm just about to start changing oil myself on my 2012 (last dealer oil change is coming up) and I'm considering using Amsoil.

I think I'll go use that handy dandy search function too...
 
#28 ·
If you switched your engine oil and rear diff and maybe you transfer case you 'might' see a 1/4 mpg increase. So yes, you will have an increase and yes it will be that small (0.25) and you may not even see it.

Amsoil will provide no further mpg improvement over any other high quality lubricant. I say this based on experience and data tracking, not promotional sales data or rhetoric.

DEWFPO
 
#30 · (Edited)
I wonder how things will react with a hotter tstat?.

Sounds crazy but Toyota runs this engines super cold. Whats the stock tstat, 160-165F? Most I've gotten out of the FJ is 270 miles with 16.004 gallons. This is with the gas needle flush with the lowest portion of the red mark. Good to know there are 3 more gallons in there. Mine is m6, so the awd doesn't help:).

In contrast I've a 6.0L powered GM car, 4 doors, 4000lbs, with about 360rwhp or about 420fwp, assuming 18% loss through the A6 trans, and a 3200rpm torque converter, and I can still get 350-360 miles out of the tank (freeway). Its also a 19 gallons fuel tank , but with the gas needle all the way down, to the lower portion I have guevos to take her, I'll pump 18 gallons. My car runs hotter about 199-201F in the fw. Not saying the tstat is the only reason I get better mpg with a bigger motor, but we loose mpg when people do cooler tstats. GM LSx engines run more efficiently at 199-205F.

Has anybody ever try a hotter tstat, while keeping an eye on the engine vitals with an odb2 scanner?

Sent from my Nexus S4G | 4.1.1 AOSP JellyButt v2.4
 
#31 ·
And a cai should help a little as well. From what I've seeing with my dashhawk (similar to what you guys use, scangauge or similar, dashhawk is older but it works with the Toyota can bus) the fuels trims with the stock calibration and stock engine are about 2%. I'll get a cai later and see how off from this number the fuel trims would go. Hopefully no more than 4-5%

Sent from my Nexus S4G | 4.1.1 AOSP JellyButt v2.4
 
#32 ·
I have said it 100 times before and I will say it again:

The reason people's mpg varies so much has more to do with how they calculate the mpg then any other method. I had my speedo calibrated and its certified accurate at 65 mph now. I am seeing 16.4mpg average based off odometer, and GPS measurements. If you are using a scan gauge it is NOT a super precise device that can tell you exactly how much fuel is used. It has no means of measuring actual fuel flow, just a calculation based on sensors/ ecu parameters such as injector pulse, and throttle position. The scan gauge is accurate in certain circumstances but not others. Just as I fooled a 2010 Chevy Tahoe into calculating 35mpg on a 220 mile trip by keeping it running in cylinder deactivation mode and coasting a lot. When you start throwing in 99mpg numbers into the works your mpg will skyrocket despite the fact it really isn't going up. To much weight is put into the infrequent very high mpg numbers.

The reality is your not going to get over 20 legit mpg in a fj cruiser that's a auto and 100% stock, as a baseline for all the time. At freeway speeds of 65 to 70 you are going to be below 20mpg unless your driving downhill. Most fjs will get 16 to 18 mpg average stock, and if that's not acceptable it's best to find a different vehicle. Or spend 3k dollars putting some light weight aluminum wheels with light street tires, re gear the axels, and even just buy a 2wd model. You can get 30mpg with some other awd/4wd vehicle, but it won't have a actual frame, serious off road capability, or as much room inside.
 
#33 ·
If you are using a scan gauge it is NOT a super precise device that can tell you exactly how much fuel is used. It has no means of measuring actual fuel flow, just a calculation based on sensors/ ecu parameters such as injector pulse, and throttle position. The scan gauge is accurate in certain circumstances but not others. Just as I fooled a 2010 Chevy Tahoe into calculating 35mpg on a 220 mile trip by keeping it running in cylinder deactivation mode and coasting a lot. When you start throwing in 99mpg numbers into the works your mpg will skyrocket despite the fact it really isn't going up. To much weight is put into the infrequent very high mpg numbers.
Don't know about Tahoe, but when I compare actual gas on gas station and what SG-2 tells me difference is 0.1-0.2 gallons maximum , for 16 gallons it is 1-1.5 % if I using same pump and same gas station.

Also I have HYPERTECH speedometr calibrator, to correct distance (checked by GPS also to make sure)
 
#34 · (Edited)
Guys are running modified from stock trucks without speedo calibration. Not to mention modifications done such as headers, intake pipe, exhaust, etc can affect the tools accuracy. Under ideal circumstances you will see accurate results. A non calibrated speedo, modifications that affect the quantity of fuel needed, higher then normal fuel pressure, accuracy issues with certain sensors, etc, will all play a role. I have found that the tool will average incorrectly under circumstances with a fair amount of coasting or heavier throttle use. The fjs don't get very far on a tank of gas which further makes it difficult to calculate averages properly.

The gauge is accurate to train good habits on the use of the throttle. Uhaul has been doing the same thing for a very long time, except they use vacuum gauges. A vacuum gauge is on the a-pillar on the drivers side. As you open the throttle the needle dips (due to the loss of vacuum). The further the needle dips in the red (the more throttle your using) the worse the gas mpg. Same idea, and has the same results.

I have been playing around with laptop versions of software just like the scan gauge uses, since the late 90s. This tech is not new, this goes back to obd2 in 96. Sure a lot more sensors have been added since, but they all calculate fuel consumption based on a set of stock ecu calibrations which are based on a stock engine. When you deviate from them at all the accuracy goes down hill. My buddies modified 2004 gto has a scan gauge, a onboard ecu run mpg estimator, and I have run diagnostic software on it during the build up. Everything was pointing that he was getting much better fuel economy then he was (laughable 30mpg out of a 454 LS motor). None of the sensors on modern cars measure fuel flow directly, it's not needed since you can calc out estimated mpg based on injector flow per pulse, and number of pulses. However if your fuel pressure changes, the amount of fuel changes per pulse. If you swap injectors this will also throw it off, and as injectors age/flow less, or are more inconsistent between all of them there will be cal issues. Not to mention different blends of fuel will affect mpg as well.

This isn't to discredit the use of a scan gauge, they can serve a purpose. However there are so many variables between fjs and the area they are in, the mpg will vary wildly. Bone stock it is to be expected to get 18 to 20 mpg stock with a auto and 16 to 17 stock with a manual for a average. Heavily Modified its to be expected to get 12 to 16 mpg with the auto and 12 to 16 with the manual. If your pulling over 20 mpg all the time out of a stock fj your calculations are likely off a bit, and if your getting less then 15mpg stock then something's wrong.

If the stick shift had a 2wd transfer case, and the same gears as the auto, it would get better mpg then the auto. However when going to bigger tires the manual will return more mpg then the auto. I am a averaging 16 to 16.5 mpg out of 7 tanks of gas, with steel bumpers big trail grapplers, 3 inch lift, and 300 pounds of gear. If I could not run in 4wd mode all the time I would likely pickup atleast a mpg. Around here it's rare to get that mpg with as modified of a truck, with a auto trans even in 2wd mode.
 
#36 ·
The reality is your not going to get over 20 legit mpg in a fj cruiser that's a auto and 100% stock, as a baseline for all the time.
I beg to differ. If I get less than 20 mpg in my normal everyday driving (no trail riding), then something is wrong. Mine is 100% stock and an late 2006 model. I've posted this many times going back to 2007 on this very forum.

I agree with you that there are so many different parameters that affect mpg it's extremely difficult to compare one situation to another. I could easily list 25-30 factors off the top of my head, some of which have been mentioned here already.

The best we can really compare to are averages.

DEWFPO
 
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