hello from socal, with my v6 brick

[foppert]

Hello everybody, I am a Northern CA local living in LA with a 1989 4runner 3.0 v6 5speed. I am hoping to learn how to squeeze what i can out of the engine and drive train to get as much MPG as it can manage as i would like to make the truck a road trip vehicle. I already drive it easy, mostly the speed of traffic and rarely reving past 2k on accelerations (you should see how frustrated drivers are behind me at stoplights.)

The truck is about to turn 250,000, but take pretty good care of the engine and drive train with routine maintenance, (fluids, plugs, wires, belts, and lube of suspension and drive train), But everything is bone stock. It is my daily driver and does mostly highway. I do use it to haul stuff often, including a hitch mount motorcycle carrier.

So initial questions i have, currently the truck is running on 31 inch BFG AT's. I do use the truck occasionally for offroad/snow use which those tires excel at, but i am thinking of having two sets or rims, one set for onroad/snow and one set for offroad. I figure if i make the switch i can find a set of the stock Toyota alloys that would have come on the nicer trucks and have the option to run smaller tires. So, do you guys recommend running the stock 225/75/r15 that it says on the door or the larger tires. The tires i am looking at are the Firestone Destination AT's, as reviews say they are very good for AT and truck tires, and they are less aggressive than the BFG's

Something that is a bit concerning is at 70mph which is normal LA freeway speed the engine is turning 3k rpm, and i know these engines are semi famous for not liking to rev too much higher than that. With the age of the truck id like to not blow the engine just by trying to not get run down in LA freeways.

My other hobbies i mean vehicles include a 1977 yamaha xs360 , and a 1967 beetle (modded to use as much gas as possible....) But hey i came here to focus on the daily driver.

[cRiPpLe_rOoStEr]

Have you never considered a Diesel swap?

[foppert]

I have, the engine swap i was looking at doing was the 3.4 swap as it is less intensive than trying to swap for something like a Mercedes diesel. I figure the 3.4 is a more effiecent v6 and the engine will have less effort at speed. It also bolts right up to my current transmission. If i were to change out engines for more work i could do the 22re that used to come in these trucks, but it is not a straight forward swap. I also have to contend with california smog laws and im not sure they would look kindly on me importing a diesel from another country. But i figure for now id like to do what i can with what i have, (i figure this engine has at least another 50k miles before it quits.)

[jeff88]

Welcome from a fellow 4Runner owner!

The 3.4 is an almost bulletproof engine (assuming you're talking about the 5VZ), but I don't know what it would do for you in terms of MPG improvement. Maybe you could put the smaller engine with a turbo (a sortof ecoboost type of setup).

In terms of tires, I would go tallest possible for highway and road trip driving and shorter ones for the offroad stuff. This site will give you specs including what combos of tires/wheels will fit (like offset and fender height) as well as what the height is in inches. This site will show you what RPM you will see at certain speeds in each gear and what a different tire height will do for it.

Is there a different final drive that you can swap to lower the RPMs, so they aren't hitting 3k at 70?

If you're looking for better FE, best way is to change your driving habits (this happens continually) and the other best way is to change it from a brick to an aerodynamic, fuel sipping machine. Add an air dam, seal any holes in the front (like fog light openings with no fog lights), add a belly pan, remove roof racks, etc. You can also do a kammback or boat tail for the rear end. You can build a boat tail on a trailer or hitch mount and then it can be removed when you need the hitch.

If you haven't yet, check out t4r.org for 4runner specific questions.