Now you guys have me thinking.
What mods make sense if you want to increase MPG while either helping or not hurting power? I'd like to play with modifying it just for the fun, but my primary goals in order would be to:
1. Increase mpg's inexpensively,
2. Increase durability/reliability inexpensively,
3. Increase (or not decrease) power inexpensively (sensing a pattern?)
It will never be a rock crawler. I'd like to be able to tackle logging roads or iffy roads to explore places most regular people don't find to camp. I'd like to be able to pull a camper occasionally (within rated load limits).
I don't want to change the look too radically. I like the way it looks.
I'm guessing an exhaust mod might not be very inexpensive, but the cost of exhaust doesn't put me off.
For reference, this is my first 4Runner. I bought a 3rd Gen on purpose. I got it about a year and a half ago, and I'm just getting a bit of time available to start playing with it. I can't afford the time or money for a radical overhaul, so bite-size, affordable modifications are the order of the day.
I'm thinking of it as a very tame hobby as an alternative to a midlife crisis. ;-)
Maybe I should actually start this as a new, newbie thread?
Edited to add: It's my daily driver. And what does "S/C" mean?
Caution: once you start modding it never stops. I just spend the last two evenings ripping apart my trim and headliner to re-wire my dome and map lights to function how I want them. Would that be a big deal to others? No. Did I want to do it for the satisfaction and challenge of it? You bet.
Modding isn't really a "newbie" thing, you need a good understanding of your engine and truck to do any sort of mods. Anyone can have a 4x4 shop slap on a winch and bumper, but that doesn't mean they know how to use it or compensate for extra weight.
Ozarks might has some suggestions that I'm missing but here's the ones that are worth your time and/or money (assuming you are up to date on maintenance such as MAF cleaning, spark plugs, wires, etc.):
1. Basic performance mods involve the three components for combustion: fuel, air and spark. Spark, as far as I know, makes no difference on our trucks and is fairly expensive.
A. New cat-back exhaust system. This involves removing everything downstream of the last cat and replacing the piping and muffler. This is proven to improve HP and MPG's on almost any car/truck, with the exception of new models in say, the last 10 years or so. Basically, they've made mufflers less restrictive like in the past. Increasing the size of the piping 1/4" improves flow without having potential back pressure issues. Borla and TRD make the best mufflers for us.
I'd search for others who have done the same to get a feel for how much this will do. On my last truck I did it on, I gained ~3 MPG for a cost of $275. I drive about 8000 miles a year and if you crunch the numbers, the gas savings paid off the mod in just under two years. I've saved roughly $300 in gas since then.
B. You could try running synthetic oil. Some claim better MPG's and better engine protection since the oil has a lower viscosity at start up but doesn't thin out too much like conventional oil. I will be running AMSOIL in the very near future so I'll have more experience on this one soon. We noticed no difference running synthetic in my wife's Nissan Altima though, then again it already gets 33 MPG.
C. For us with turbos or superchargers, adding more fuel helps immensely. For a stock 4Runner though, it won't do anything for you. Focusing on the air side, both intake and exhaust, will net you the most MPG/HP gains.
2. A. As far as durability goes, you can't really improve the 5VZ-FE. It's a well engineered engine that will last you a long time. Keep on on maintenance and it will be good to you. So basically, this is a freebie!
B. For the suspension/steering, you can look into replacing the sway bar and steering rack bushings. They wear down over time and you will start to lose steering control and have excess body movement. Replacing these will make your truck handle better. Just did mine a while back and for $40 it's much better, I used parts from energysuspension.com, but even cheap parts of Rock Auto would help. Lower ball joints should also be replaced roughly every 150k miles, they are know to fail catastrophically.
3. A. For power, see the cat-back exhaust. Seeing a trend here?
B. Another inexpensive "mod" you can do is to eliminate the sound baffles and passageways on the stock intake. Some buy $180 air-aid intakes which is overkill. Search "Intake Silencer Mod" and you'll get all sorts of stuff. Once again though, it's not going to do a whole lot for a N/A (naturally aspirated) engine compared to a S/C (supercharged) engine but some are happy with the results.
Other than that, there's not a whole lot that will be inexpensive. After that you get ideas of overboring the throttle body, porting the intake, etc. but that is very expensive for an engine that will see little to no performance gains. Headers are also expensive and can be very difficult to install.
