Toyota FJ Cruiser Forum banner

Fuel Efficiency Upgrades?

29K views 55 replies 31 participants last post by  norm356 
#1 ·
Are there any mods that can improve fuel consumption significantly? I've heard that replacing spark-plugs can have an impact as well as tire tread, etc. Is there a speed that most FJCs seem to conserve more fuel (other than not driving at all)? Has anyone made any engine mods that have had an impact?
 
#3 ·
Agreed. Trade for a Prius. FJ's and fuel efficiency don't belong in the same sentence.
 
  • Like
Reactions: Thorn661
#4 ·
Biggest effect on fuel milage is seen with tires, and driving style. There is no bolt on item that will have a significant positive effect on fuel milage.
Lighter, less aggressive tires reduces rolling resistance, anything added to the roof line will play a role in reduced milage, smart driving is a big factor, lifting out of the throttle sooner when coming up on yellow and red lights, keeping your rpm around 2000 or under when traveling is a benefit, smooth acceleration ... All of these things help, but bottom line is the FJ is not known for good gas milage, it is a large brick being pushed down the road, that said in this class it's not dramatically worse then any other.
 
#7 ·
It's that time again.............damn this month is going by fast.
 
#14 ·
We always joked about using one of those like a lifeboat and having it strapped on the back of our trucks. About a month ago I had to laugh as I passed a full size diesel pickup with one in the bed.
 
#17 ·
I agree: Take the rack off. My experience with a 95 Nissan Pathfinder is at least 1 mpg maybe 2 drop with the rack. How do I know? I keep track of mileage and noticed a drop off when I installed a factory rack. That rack was streamlined compared to the one on the FJ. Think "Long Tall Sally" (She's built for speed) vs Kim Kardashian.

Another thing that helped on that car was exhaust headers. That got back the mileage that the rack stole and it sounded better too. I may go that route on the FJ if the exhaust rusts out.

I don't have any direct experience because I generally run aggressive tires but I suspect there is something to gained by using highway tires. I don't have a clue how much. I noticed some tires now have an efficiency note on them. Most of the drag at highway speeds is air drag so it may not help a lot. I generally run the high end of tire pressure on trips but mainly so I don't have to check tire pressure on the way.

Speed kills gas mileage. Try running 10mph slower. Years ago when they dropped the speed limit fom 70 to 55mph my Cutlass mileage went up by about 20% (from 14 to 17mpg). Expect to see a couple of miles per gal. Off set that against your additional time on the road. Your time has value.

Keeping the RPM down will help. I have a 20mile run that I make often on some pretty level back roads at 35 to 40mph (35mph speed limit and Mrs. Sheriff needs new shoes). Getting it in the highest gear seems to help. On those roads it pushes 21 or 22mph if I dial in the cruise control and stick to 35mph. I am going to disagree with the guy that says the FJ is best a 50/55mph. I have got the best milage at slower speeds than that. Downside: It is soooo slow and fricking boring.

Get a Scangauge (~$100). It plugs into the OBD2 port and gives a pretty good idea what your mileage is at any given instant. It tells you a lot on a level freeway. In hills it is not much help, although it does show the effect of even a slight incline. Try to always go downhill.

Avoid stop and go. I use a Mazda for short in-city trips.

Don't run the A/C.

Above all don't expect a lot and pray that gas prices stay low.

John
 
#21 ·
Are there any mods that can improve fuel consumption significantly? I've heard that replacing spark-plugs can have an impact as well as tire tread, etc. Is there a speed that most FJCs seem to conserve more fuel (other than not driving at all)? Has anyone made any engine mods that have had an impact?
Significantly, NO!
 
#22 ·
Seriously tho,

Bash out windshield and rear window, remove head rests, duck, and only drive down hill under 50 miles per hour.

These things are shaped much like a shed. Unless you have at least a 50 mile per hour tail wind, they suck gas.
 
#23 ·
You lost me at "efficiency."
 
#24 ·
Hey, can't hurt to ask. I figured there wasn't much that could be done - and like many of you said, it's not the most aerodynamic vehicle. I definitely didn't purchase it for fuel efficiency so I'm in no way disappointed or expecting otherwise. Just was wondering if there were any mods within reason that could be done to improve mpg.
 
#25 · (Edited)
It is actually a fair question. The reason so many of us joke about it, and come off a bit callused, is simply because this frustrating question comes up every other week. Heck I'm new here and have seen dozens of these threads.

The other reason is we all wish these things got better mileage. Inflating our tires to 55 psi helps a little, as does staying off the skinny pedal, but installing 900 pounds of iron does not.

It all boils down to aerodynamics. I can run in 4 low for days on end and this thing literally sips gasoline. I'm loving it. Granted my RPMs are down, but I'm driving 1 to 15 mph for 15 to 20 hours and still have 1/2 of tank . It is truly amazing. I honestly think this V6 does as well off road as my 22R did.

Then on the freeway, pushing air at 75 mph, running 2200 rpms, I run completely out of fuel in just 3 hours. Go figure.

I honestly believe that if Toyota would have put a larger fuel tank on these things we would be tricked into thinking it does a bit better. When I take this thing to southern Utah, there is a stretch on I-70 that has no fuel for 110 miles. That stretch begins 90 miles from my house. When the wind blows from the west like it has been ALL DAM MONTH it's a crap shoot on whether or not I'll make it the 200 miles.

My friend, in the future if you have a "common" question, it will save you a lot of heart ache if you simply google it. If your Q has "FJ" in it you will be directed right back here. That being said, these Toyotas are so reliable, that many of the threads on here are far more frivolous that this one, again, go figure.

Hope to wheel with you some day!! :rocker:

MJ
 
#26 ·
You have to remember that the manufacturers do everything they possibly can do squeeze out as much fuel economy as possible because they know fuel economy is a huge sticking point for most people when buying a vehicle. If there was an easy way to make the FJ get better mileage they would have done it already to comply with the EPA's new b.s. CAFE standards.

That said, I inflate my tires with helium because it's lighter than air, the reduction in weight increases my mpg and helps me "float" over obstacles off-road.
 
  • Like
Reactions: Deathstalker74
#28 ·
Where do you even fill up with helium? I've been wondering about this. Also, I completely agree about the larger fuel tank. I used to have a Ford F-150 with the dual gas tanks and I just loved depressing the switch on the dash when one tank was empty and watching the gas meter return back to full. Pure magic!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top