MPGs after Modifications
 

This is my first post after spending a good amount of time reading, and really being inspired by, all of your threads.

I would like to know what types of mileage you have observed and what types of modifications (that would effect mileage) you have made. I am asking this specific to the 84-85 forum with that solid from axle.

I am currently getting 16 MPG and have a 1985 4x4 Pickup with a small lift, 31x10.5 BFG All terrains, a 22RE 2.4L EFI, a Magnaflow muffler and 2" tubing from the Catalytic converter back.

I am interested because I have an appointment to take it in next week and replace the catalytic converter (I believe is shot) and upgrade to a performance header. Not long ago I replaced the distributor cap/rotor/wires/sparkplugs, but not before the catalytic converter turned red hot, which is why I believe it is shot.

After the exhaust modifications, I will be looking at new tires and gearing. I had in mind 33x12.5 mud terrains, but with the need to regear (I have a 4.10), I am hesitant (unless I want to go big and rebuild and lock the rear axle and drop a ton of cash)

I am really interested to see the modifications that everyone has made and the changes in efficiency that they have observed: per MPG and power. Really, did you find it worth while to make that modification?

:google:

some photos: http://picasaweb.google.com/PaulHudson2/TheVehicle

I have an 84 4Runner that im trying to get back on the road, replacing the stock cat will make a difference, the stock cat is a pellet type and is very restrictive. I just had my cat and muffler replaced two days ago and even though my truck isn`t running good right now i could tell a difference. My 4Runner will soon be lifted with 5'' trail gear front springs and 63'' chevy springs in the rear, i will be running 36'' tires with stock gears and duel cases from inchworm, with the duel cases there is no need to regear. it all depends on what you want to do with your truck, do you go wheeling at all, or just street driving ?.

Not the same year as yours but the same engine. I've got a 94 pickup on 33x12.50. Only thing I've really done is added a 261C cam from engnbldr.com and removed the emissions. I don't have a cat, yet have a gapping whole in my muffler that I need to get replaced. Stock gears (4.10) and get about 18 mpg. Power is suffeciant for what is being used for as now, driving back and forth from work.

84 4Runner
22R with: weber 38 carb, stock air cleaner assembly, port matched head/intake manifold, TRD stage 2 cam, LCE header, 2 1/4" exhaust, flowmaster 40, NWOR distributor recurve, cant remember what else

Drivetrain: G52 trans, stock 4.10 gears, 31x10.5 BFG ATs

In the summer i can sometimes get 18-19 on the highways, with mixed driving usually yielding 16-17mpg. In the Minnesota winter, it is usually more like 10-12mpg. Power with this setup is pretty decent for a 4cyl truck with bigger than stock tires, but I feel that there is still a bit of power and economy hiding in fine tuning the carb.

I too have a 22RE 4Runner, though mine is 2nd gen. I have a pretty much stock 4Runner with no engine mods. The only mods I can think of that would affect mileage are that the rear is lifted a bit so its a little raked and I also run 31's with 4.10 gearing on lots of hills. I get about 17 mpg.

i average 16. except when driving up to tahoe ill get around 14. this is with my built truck. the only engine mods i have is lc header with downey cat back exhaust and downey air cleaner.

I'm planning a trip through Mexico and Central America and I imagine that the majority of driving will be done on paved (paved in terms of the developing world) with significant stretches of off road trail riding. I do not plan on any aggressive wheeling or rock-crawling.

http://picasaweb.google.com/PaulHudson2/TheVehicle

Besides the piece-of-mind of having a dependable vehicle, I would like to spend the money now, optimizing performance and maximize my vehicle's fuel efficiency. The way I see it, working on these factors now will make the drive a lot more fun (with the added power) and get me more miles between fill-ups (when gas stations are scarce).

Now the big decision is tires. Do I go bigger, lowering Mileage by an unknown variable, or remain constant with the 31x10.5.

id stay with the 31's. there are somethings you can do to get better mpg and power. such as cleaning out intake manifold. heres a link on a good write up on how to do so.

http://www.wildyoats.com/hp_under_$95.htm

you can also upgrade your air filter to a K&N

IF you Do replace the old stock CAT dont forget that old cats are worth BIGGGGG bucks i got 100. at a scrap yard for my old stock cat!

What are the old catalytic converters made out of that make them so valuable at the recycler?

There's some special element that actually cleans the exhaust. I wanna say its platinum... or zinc. Heck I forget.

I'm running 33/12.5/15 Firestone Destination M/T, heavy tires + aggressive tread = greater roll resistance (poorer fuel economy) I lost an average 2-3 mpg with my tires. But I love the off road capabilities. Heavier sidewalls = lower psi off road and side lugs more treaded foot print at lower psi.

other stuff.
K&N
Doug Thorley header
High flow cat
glass pack 2 1/4" pipe
EB 261 crawler cam
4:88's and lockers
20-21 mpg before tire change 17-19mpg after

Ok, so the stuff in cat. converters is platinum.

I've had my headers and exhaust on since I got my 4Runner, so I don't have much to base it off of, except my friend's similarly equipped runner, which gets around 17-18MPG stock. I used to get about 18, fairly consistently. With my K&N intake, I get close to, or over 19 MPG just about every time. My driving habits don't really seem to reflect my MPG. With the exception of whether I'm driving on the highway, or around town. It snowed over by me last week, and I had it in 4WD HI for about 30 miles, averaging between 25-30MPH, and earlier that day, I was driving 80MPH on the freeway for close to 80 miles. When I filled up again, I averaged 19.4 MPG.

So I just got my truck back with Doug Thorley Header, MagnaFlow high flow cat and a little adjustment of the valves. Wow, does it drive well. There is a big difference in the torque and just feels fun to drive. I'm interested to see what kind of mileage I get on this next tank, but really, the increased hp made it worth while.

http://picasaweb.google.com/PaulHudson2/TheVehicle

I'm thinking about some lights next, that is cheap.

Getting all excited about working on the truck, I impulsively ordered a new set of tires just now. four 32x11.5 BFG ATs. I think I'm about to loose all the torque I just gained, but I wanted the tires a little wider, and I can use the same rim, I hope?

I'm gettin around 16-17 freeway, but just waitin on the Thorley header I just ordered, what brand hi-flow cat is the best on the market?

I rebuilt my engine, stock cam, stock carb, header(used from autowrecker-$25), 2" exhaust, 4.88 gears, 4spd trans, 33" tires, Highway rpm is 3200 at 65mph. I get 18.5miles per U.S. gallon in summer driving to local mudhole, offroad all day, then driving home. My next mod will likely be EFI. Been told will get me 3-5mpg better than carbed + 10-15 more hp. I find those numbers hard to believe, but $600 for the setup to for sure solve the hill climb stall problem is reasonable. If i get better mpg, great!!! Before re-gearing on the 33's- I got 14mpg- REGEAR FOR BIGGER TIRES!!! It works! Remember these 4cyl motors LOVE to rev!