If you have upsized your tires the odometer is slightly off. If you upsized tires you're actually traveling about 4% farther than your odometer is telling you. As a result, your MPG is not as bad as it appears per the caluculatiuon based on the odometer reading.

Like others have said, larger tires do decrease MPG but they also make the odometer spin a little slower becasue you are actually traveling farther than the truck thinks each time the tire rotates.

The best way to get milage is via GPS. The odometer caculates milage based on the number of roations a tire makes. If the size of the tire changes from stock, both the speedo and odometer will be less accurate.

So combined the data looks pretty bad.

Bigger tires = worse gas milage
Bigger tires = inaccurate odometer and that makes it appear even worse

der
 

i put 4.88s in my std cab 3.0 to make it easier on a tired motor took more gas an was sloooow. i put back in the 4.30s an 3.4 swapped so no worries. if your beatin pavement with 31's then stay stock especially on the interstate where your goin faster than normal, why go through the pain in the ass and money for a slight difference that wont improve mpg's unless running bigger tires

INSTALLED A HYDROGEN FUEL CELL FOR 25 $ ..SIMPLE INSTALL..WENT FROM 11-12 MPG TO A SOLID 15+ FOR SURE AND ALSO NOTICED A BIT MORE TOP END POWER IN 5TH GEAR.....THESE THINGS WORK TRUST ME.....http://shop.ebay.com/?_from=R40&_trk...All-Categories
ALSO INSTALLED A VACUUM GAUGE KIT... AND KEEPING THAT NEEDLE IN THE GREEN WHEN DRIVING HELPS TOO

2010 FJ TRAIL TEAMS
1994 P/U 3.0 2.5 LIFT W/ HYDRO FUEL CELL

Yeah the 3.0 you cant get better MPG with anyways.
I put 4.30's in mine and went up a few MPG's. Didn't notice any loss of highway performance, still barreled down 211 at 80MPH, lol.
As far as diffs are concerned, well, i bought axles and they have 4.30's in them. Soo... i used one. Was cheap.

I'm confused... I hear the HHO is a joke and I hear people saying that it works and are using it... The science seems a little off to me but if it really works then Id be interesting in doing something like that.... Who knows what they are talking about? As in who has tried it and knows for a fact it doesn't work...

Lets see.......

Supra AFM (MAF, whatever you call it).
LCE header
Cone filter on the Supra mod with a semi-sealed cool air intake into the cowl
4:56 gears to match the 31's

That's it so far.

Oh goodness.

With a 22re you'll need 4:10's for stock tires, 4:56's for 31's, 4:88's for 33's and 5:29's for 35's. This is assuming you have a 5 speed. With an auto it changes a bit.

I've driven with 31's and stock 4:10's, slowest 2 days of my trucks life.:hillbill:

In theory you should get better mileage with 4.10s and 35s than with 5.29s and 35s because the elms will be lower.
However in a Toyota and 4.10s with any oversized tires it takes ALOT of energy to get moving. The thing with higher gears is that YES it does raise your rpms up but it requires less energy to get moving equating to better fuel mileage.

youre also gonna have to keep your pedal at like 1/2 to 3/4 throttle to maintain a good highway speed which will use more gas like you were saying, and just go ahead and forget maintaing speed uphill without running 3500+ rpms and flooring it. i have 32's and 4.10's and i can hardly hold 60 on slight uphill in 4th, gotta go to 3rd if its steep, and thats with a fresh motor

go to youtube and see all the videos .....these things do create hydrogen w/ 12 v and a few amps ....(less then a 50 w fog light) get one... power it up and put the out -put tubes into a jar of water and hold a match over the rising bubbles and see what happens..... its a very combustible gas....so suckin this stuff into your vacuum on the manifold adds to the air fuel mix creating a free combustion source that only needs water every few weeks...listen you would need one bigger then a garbage can to run a 4 cyl engine alone without any gas.....but yes ..the theory...and the truth is they work..

1st and only warning. Keep the thread on topic. And keep your opinions to your self. This thread is for factual mods that have helped others. I'm looking specifically at you jessed59.

I had an 88 manual with the 3.0. It had 235's and I also put a jacobs ignition which was probably around $300. I don't see them made anymore. I put jacobs wires on to match and also indexed my spark plugs. I took about a 2000 mile round trip out to Utah and back and I was driving like a bat out of hell. I probably averaged 90mph most of the way and I was getting 23mpg. I could easily hold 85-90mph driving through the rockies, even uphill. I put 254 miles on one tank and it came out to almost 25mpg.

Those are the only mods I had done to that truck. I am having problems with mpg in my current 1993 with same motor, tranny and diff's. Only difference is 31" tires. Thinking about indexing the new plugs I just put in, changing wires cap and roto. 13 mpg average just doesn't cut it. I miss my 88 at this point!

the best mods that i have found are only on carbuerated 20r/22rs as that is all i have ever owned

#1, make sure your charcoal filters are hooked up to vent the expanding gases back into your carb.

#2 EGR and PCV dont REALLY need to be hooked up. I just have mine vented to the ground ( no emissions of any kind where i live) so the engine doesnt have to burn that crap again.

#3 manual conversion:horse:

#4 antenna delete, my truck came with like 4 antennas on it, just took those off, and it made a slight difference.

#5 manual choke. Youd be suprised at how much a difference this makes, having control over both fuel and air is really interesting..

I am averaging 36 town and 38 highway. I dont accelerate klike a madman either.
running a 20r 2wd with a weber

I have a an 89 22re 4x4 extended cab with 31x10.50s with the stock 4.10s and average around 17-18mpg (50% city, 50% highway). I have had it to 22mpg on the interstate. I calculated these numbers with a gps. truck is completely stock other than a k&n filter and no cat and 62k on a rebuilt engine. as far as being slow, i got it to 96mph one time on the way home, it has no problem getting to 80 but it is slow until it hits 90, then it picks up a little.

There are 2 key factors that help me get decent mileage. The first is driving slower. 55-60 on the highway. Easy starts from stoplights. The second, is air pressure. I run the fronts at 36 and the rears at 30. I'm averaging 20-22 mpg on 87 octane, 30" tires, auto trans, and a laggy turbo. My best? 25 mpg, driving 150 miles on the highway at 55.

Hello
Cool thing about the hydrogen. I went to the link you provided but there are many items there. Can you be more specific and give product name or item number. I'm anxious to try this. Sounds so cool

Thx a bunch.
David

the best mod i made was swapping a built turbo motor. going from the 50k mile brand new longblock engine (22re) i was getting 16 on a good day, after installing and tuning the turbo motor i'm knocking down 21-23 and i know i'm driving it way way harder now. the truck is a 92 standard cab, 4x4 with a auto. 31's and cranked the torsion bars to level it out. it's also carting around a few hundred pounds of stereo equipment i'm sure i'd pick up another mile or two by shedding the associated weight but what fun would that be?

+1 but on a long enough timeline nobody can afford to drive anymore... Hence the usefulness of this thread.

I added .4 liters of displacement... Helped the mpg a lot!

I had an 84 standard cab, short bed running stock everything, I mean everything as in the 1" exhaust, 5-speed, stock gears, 22r, 200k+ hard hard miles, burnt 1/3 quart of oil every fill up, and I could easily pull off 23 mpg with 235 tires running over a massive canyon twice a day. I had 32's on for a little while, and not counting for the odometer being off, I could still pull 19 pretty easy. I could pull 65 the whole way over the canyon with either tire in 4th gear. The 32's required a little more power, but not much