hi guys i have a 1978 2wd short bed with a 4spd and a 4.11 8 inch rear end. my engine trans have over 300k on them and are ready to be replaced. i have a w56 5 spd out of a 1994 2wd im going to swap in and i want to build an engine mainly with mps in mind my question is what does everybody sugest for mpgs or what kind of mpgs do you see with your current builds. i want to stay with a toyota engine and not wanting to go efi unless i really need to. i am open to a 22r 20r or even a hybrid 20r/22r engine which one of these would theoretically be better on gas and what is recommended for the build up. i plan on buying a core of whatever engine i decide and doing a complete rebuild and some headwork will a port and polish job help with fuel economy also bigger valves cams what carb? should i change my diff gearing? any insight would be greatly appreciated thanks in advance you guys are the toyota mini masters

 

I get 22-25 in town and 27-31 on the highway with my 78. It has a w52 5 speed, 4.10 8" rear, 1981 22r block with 20r head, 10.5:1 comp, weber 32/36 carb with jets up sized a few steps, header, 2-1/2 exhaust, msd blaster 2 coil, Taylor plug wires, ngk plugs, ported intake manifold and head. Tons of power. Biggest change I would make is step to a 3.0-3.5 range rear end. I run a 215/60/14 tire which is about 24.2" tall. I run about 3000 rpm down the freeway. Hope this helps.

Any work to make the air flow smoother and quicker will help mileage. Stuff like headers, bigger exhaust, porting work on the intake (can provide more info and specifics), head work, ect. I do not have an aftermarket cam, I couldn't afford it when I built the engine.

 

thanks for the fast reply i knew you guys would have some imput i guess i shouldve mentioned that i am running 205 55 15 tires and that i do 85% of my driving in town from stop light to stop light. do you think that the 22r hybrid motor has better potential to be a gas getter than a 20r by itself ot a 22r by itself.? also i do plan on going with a weber 32/36 and getting an exhaust with header and possibly even an intake if that would benefit my cause.

 

also i think i should mention that ive been a member of this forum for a long time but mostly all i do is read your guys posts and drool over pictures of your rides but now i thinks its time i introduce myself and my truck so im going to attempt to post some pictures on here and i sure hope i can figure it out.



edit: i tried to upload and couldnt figure it out sorry guys.

 

There are aftermarket intakes but I like porting the stock one. Gasket match the head end and remove the casting flash and texture. On the plenum end, cut the crossbar between the holes out and smooth whatever you can. For the 20r engine the intake has a better flow path. As with the head to the valve. The 22r has a larger piston though, on 81-84 it's domed. So using the 20R head on that bumps compression since the 20r head combustion chamber was designed for a flat piston. Either motor as is should get good mileage.

 

I didn't brother reading past the first post---- If you want better MPG change the rear end gearing!

4:11 are very low = bad MPG!

 

Yup^ a less aggressive gear and put that 5 spd in

 

My opinion of final ratios
4.0 or more = Great with loads but high rpm on highway.
3.0 or less = Great for low rpm highway but struggles with loads.
I think the G-series diffs started at 3.5:1. I think automatic supras are 3.9.

 

i have just done a bit of reading on how higher compression ratio should produce better mpgs so for this purpose my engine build is going to be a 20r/22r hybrid engine. i have already located a 20r head i should be picking it up this weekend i will get all my headwork done and then start looking for a early 22r short block

 

so should i do an axle swap or just change out my gear ratios. i actually feel like my axle is a little narrow and wouldnt mind swapping a wider one from a newer pickup however i want to keep the 8 inch diff as it is stronger. also the large majority of my driving is in town from stop light to stop light and i wonder if lowering my gear ratio to much would actually be worse for around town mpgs.

also as a side note ive been wondering lately if anybody knows the approximate weight of my 1978 short bed. no a/c or p/s or any accessories really at all

 

after adding the W series trans, i would just go with 3.73 gears in the diff and call it a day....

 

That's only going to get about 24-27mpg (maybe a tad more with the weber and 20r head swap).

because it's a W56, i'd consider somewhere between the 3.4x and 3.07 gear sets. You'll still be able to take off thanks to the 1st and 2nd gearing, and you'll improve cruising mpg.

I wouldn't go below the 3.4x if it were a W55, and probably wouldn't want to go below 3.73 if it were a W58 or W50 without some power mods. This is just my personal opinion. It doesn't mean you can't gear lower, but starting becomes more and more troublesome the further you go (higher revs required, possible more clutch wear).

 

not true, i ran a W56 and ran 3.73 gears on my completely stock (other than k&n and cheap magnaflow muffler) '88 xtracab and i got a solid 34mpg.

i was really surprised cause i was averaging 26 with the old G series trans, but when it took a **** and i picked up the W56 from a friend, i was really floored a the jump in mpg.

 

Was it fuel injected?

Whether it was or not, we're not talking the more efficient 85+ years of 22r motors, this is the earlier style with the domed pistons. They didn't produce power quite as effectively as the later years.

 

Ill agree with that ^^ in stock shape. Sounds like the OP is going to build a mild hybrid. A 3.5ish would be perfect if you stick with a 26"ish tall tire. And it weighs about 2400 lbs empty. My long bed is 2540 or so empty.

 

negative, original asian 2bl carb. granted all my driving is strictly highway driving with a speed of constant 70mph.

 

Might have been a little off on the speedo and odometer but that's not far off of all highway mpg possibility. I've gotten 31.5 doing 65 for 250 miles in mine when I had the 20r with good weber setup and header/2.5" pipes.

 

Changing the gear ratios out would be easier. Trying to get another wider diff to fit up is a bit fiddly unless someone knows a near straight swap.

According to the american brochure the 78 short bed is 2430-2460 lbs (1102-1115 kgs).

 

thanks to all this is some great info and 2400-2500 really isnt that much weight for a pickup truck that can haul what ours can. however i was considering to some weight reduction until a really really looked and my truck and realized that its so simple and so basic that there isnt anything on there to take off i am however thinking of removing my smog pump and installing an electric fan conversion from lc engineering to take some of the load of the engine so the only accessory the engine would really be driving is the alternator. also i need to inform everybody that ive made a mistake in my previous post about my transmission i personally removed this trans from a 1994 2wd pickup with 106k miles on it and i assumed that because it was a 94 that i had myself a w56 however i was wrong i have just learned that it is in fact a w55. the major diffidence between the two is just the first and second gear ratios do you guys think that it will make enough of a difference that i should ditch this minty w55 in search for a w56? is there a way to swap the first and second gear essentially transforming it into a w56? sorry for the long post guys but this is the first 22r that ive actually been serious about and im wanting to do it right the first time

 

Electric fan conversions can be done way cheaper than a LC kit unless you prefer LC
And save some cash You can get a e fan from summit or jegs for 80 or less in sizes all the way up to 18 inches .make your own harness or use one of there auto on with manual control override fan wiring kits . I use a 10 inch single slim fan 35 dollars own wiring harness 5 bucks
Even junkyard e fans work to .