greetings from a "homeless" full time RV'er
 

Hello there!

I'm driving one of those Toyota 22RE motorhomes full-time, and working on getting my gas mileage up. It varies wildly, but I've never seen better than 15 and I know it can do better. I've already purchased an MPGuino, and I enjoy "playing the game" with the AI and gas mileage gauge whenever I drive, say, a Prius, so I plan to eventually rebuild my dash using that and a Raspberry Pi to get all kinds of data and also make my driving more efficient + comfortable. Solar is also on the list. It might result in my truck looking like the Delorean from Back to the Future, we'll see.

I'm not computer stupid but I am a little car-stupid, so I still need to figure out how to hook some of these things up. I don't really live anywhere, but I'm kinda near DC a lot, helping with stuff in Maryland and Delaware. If anyone wants to jump on this project or see it ever, drop me a note!

Like this one?

https://ecomodder.com/forum/attachme...1&d=1565061485

very similar! mine is a coachmen offshoot with a much more pointy body. 20 feet long. also, if I had to guess, that's the V6 toyota front end on a mini-winnie, mine's (as dictated by 22RE) the lowly 4cyl 2.4.

Welcome to the site!

Manual transmission?

Didn't those little toyota's come (optionally) with a small diesel?

4spd OD. Switching to manual has been considered, but I'm really poor. I think what I might do instead is implement my own cruise control using the aforementioned Raspberry Pi, once I discover what works best in driving it.

I've heard of people on YotaTech doing diesel swaps on their Truck/Hilux/4Runner (I think with the L series?) but I haven't ever heard of someone that's done it with their RV. I always see 20R (in 70s models like the Chinook), 22R in the models immediately following that including some early Dolphins, 22RE easily most common, and late 80s models and up with the 3VZE. I did a lot of research on whether I should get a 4 or a 6; generally speaking there's a tiny bit more torque and hp in the V6, and a tiny bit better FE with the 4cyl. So I went with the 4cyl and figured I could deal with going slow uphill.

I figure I should mention that much like my comment about a trans swap above, an engine swap is not really in the cards, really any modifcation to the vehicle that is gonna cost me more than a few hundred dollars is just not in my budget.

A truck is a truck.

A typical Class C of the late 1980s was 7-9/mpg. So your little box is already “there” as per its specification. Double that of competition that though larger didn’t offer much more except space.

1). New shock absorbers
2). Examine tie rod ends, front end, etc.
3). Adjust out any steering slop at dead-center
4). Exhaust back pressure check.
5). Brake drag
6). Alignment

There’s more, but you’re strapped for now. Must mean California or PAC-Coast. Best is to leave for a better place.

The Moho penalty is in acceleration. Not enough engine. It’s only “right” on the highway. And then at a steady-state 1980s 50-55/mph. Burns too much fuel any faster as it’s working too hard.

The sweet spot isn’t anything but use. Planned use. Moving it as little as possible. And then when traffic is lightest.

As the cost of ground rent is higher than fuel cost, learning to accept what this vehicle, is best. The focus should be on reliability. All new fluids, hoses, belts, filters, spark plugs & wires. New battery & starter cables. NEW VEHICLE GROUNDS. Exterior lamps to LED (priority).

Tire selection should be consultation with dealers. Tread design will matter.

If this vehicle is being used daily to commute and it’s seeing 15-mpg, you’re doing well.

Find schematic and get vehicle electrical grounds REPLACED (or at least cleaned & re-secured). Add a few across doors and hood.

Front end is in good shape, as is alignment and brakes. Haven't checked out the exhaust or the shocks, but I haven't experienced any problems with that. I see people getting 18-20 so I am not shooting for crazy numbers, just a little bit higher...

Shocks don’t last 40k. The hydraulic fluid may remain, but the gas charge has dissipated. IF KYB makes a set, they’re a bargain-brand BILSTEIN.

Gas-charged shocks are an innovation along the lines of electronic ignition: they work BETTER, LONGER and with distinctly improved performance.

Check for on-center steering slop. Adjust it out. That, and new shocks are a revelation.

Use a CAT SCALE to set tire pressure. Get a cold reading after an overnight stop before sun heats tires. Record.

At Scale, Steer & Drive Axle loads are shown separately. Use a Load & Pressure Table to establish the minimum. MORE than is necessary screws you on steering, handling and braking.

With a truck (especially one vulnerable to cross-winds) it’s the REDUCTION of driver input and degree thereof. Coupled to time. LESS IS BEST.

I’ll assume you’re using FUELLY already. Tank by tank MPG records are fairly meaningless. It’s an AVERAGE over 3-5k miles where it STARTS to make sense.

1). How long since front wheel bearings serviced? Time over miles for priority.

2). Same for rear axle fluid and wheel bearings. 15k or one year on oil. And, at thirty years, the rear wheel bearings/races should be examined and serviced.

If you don’t know how to adjust drum brakes, now is that time. A monthly service. Auto-adjusters notorious for not working well.

In that range, a bit higher still translates to a fair bit of gas.


Forget the aero stuff
A brick will remain a brick unless you do massive aerodynamic modifications - on the rear .

Driving habits are going to be your best bet.

https://ecomodder.com/forum/EM-hyper...ecodriving.php

Move it less & combine trips
Drive a bit slower - if you don't already
Drive with load, and as if without brakes
Pump up the tires

I've wandered into Introductions sort of at random. This sounds like it's worth a build thread.

slowmover isn't wrong, and euromodder is right about 'the nut behind the wheel' but look around in the Aerodynamics subforum.

Since you espouse a coder mindset, I used Mac OS Summarize on your post:
Unfortunate that it dismisses the wish for a Delorean makeover. I'd suggest a plan that is half drivetrain and half aero. Major work on a vehicle you be homeless in sounds problematic. Consider a mild hybrid conversion using a 20hp altermotor and serpentine belt to replace the 4-cylinders' alternator. Then the majic electronics and a lithium-ion battery pack and you don't need shore power.

For aero, a full bellypan with difusser is worth the work. The bottom is as important as the top. Moon disks or coroplast simulations. A big problem, plus probably acoustically, is the side mirrors. Reduce down to the legal requirement* and use dashcams for visibility. You can put mirrors inside the side windows to cover blind spots.


* I'd go with street rod 4" round peep mirrors [with built-in turn signal repeaters] hung from the underside of the cab-over. And pool noodle half-rounds behind the cab doors.

https://ecomodder.com/forum/member-f...01-2-04-41.png

One doesn’t know if 18-20/mpg is a VALID comparison without details:

Exact vehicle spec
Climate
Topography
Percent of engine hours at highway speed.

Orbywan did up a Class C a few years back. Great aero work.

ZERO mechanical slop or binding. On a thirty year old vehicle, not likely without thorough examination. Good enough to get down the road isn’t the same. One starts by measuring body height all around (use the Cat Scale).

Reliability is more important than MPG. RVs have at least two electrical systems. Replacing grounds (braided strap) is a basic; do it first. BATT cables are second round of replacements. (Because it’s present doesn’t mean it’s good. Read on subject matter). A Moho has 10X the failure points of a car. Get to reading.

Feedback is a big help for while driving. ULTRA GAUGE or similar.

Seat posture; mirror adjustment; LED exterior lighting.

Sit close. Feet on floorboards behind pedals. Arms should be relaxed at 12:00 on steering wheel. No pressure under thighs near knees. Adjust mirrors to show vehicle sides. Convex mirror more important and needs to be larger (wider).

It’s the little things. In your case it’s three decades of basic neglect. RVs just sit around. MPG is going thru it all. And most work is labor versus parts.

After steering and no binding (plus new gas shocks for body roll; and poly anti-roll bar bushings), vehicle electrical as above is critical. Grounds & cabling.

Then (only then) is engine testing worthwhile. (This assumes transmission also operates according to book).

1). Compression test

2). Carburetor operation (past choke operation)

3). Vacuum leaks (replace lines and connectors. Take one at a time ONLY while at parking lot at NAPA to get new).

I’ve recommended reading. And feedback. A dash-mounted vacuum gauge is ALWAYS worthwhile. Reading that and spark plugs can tell you a lot.

It MIGHT NOT account for your 15 and their 18 (as conditions encountered mean more).

Start asking around. Not everyone can fine tune a Kettering ignition. Or diagnose a leak at a throttle shaft. But they’re out there.

Be willing to spend time and get dirty.

The RV portion is more work yet. DON’T expect to just drive around shaking that wood-frame farther apart without problems.

First tool specifically for the RV is a Moisture Meter. Water is what destroys RVs. And what you’re driving has a cheap roof design. It doesn’t last ten years, much less thirty. Find the problem areas and read on how to make emergency seal repairs. Roof replacement is in your future.

I passed a guys biz in Mississippi recently and thought of you. He had six Toy mohos. All with blue tarp “roofs”. Probably making them road and inspection worthy to re-sell.

The truth about using a Moho is that FE is beside the point. It is what it is. It’s the RV that will always need the most attention.

At the age of yours, that BIG problem is from fire. Starts in the walls. Wiring runs strained at the junctions.

Can you get out the emergency exit? Do you know where it is AND HAVE YOU PRACTICED?

Get used to doing without electricity. That hobbles Millennial Americans so much it’s pathetic. Make your use specific and limited. READ. I watched one burn the other day. Gone in under 5-minutes. Thankfully, only the dogs and cat got roasted.

Install a Master electrical switch. This dumb broad didn’t (no husband tells all one needs to know). Leave it OFF as normal. Turn it on to cook dinner, etc, using one appliance at a time (Hot Plate means no water heater simultaneously, etc). Keep loads LOWEST while running.

Each system is just that. Not isolated pieces thereof.

Some day you may have full capability. But broke & poor isn’t that day. Until then get to the used bookstore and get some RV repair manuals. Start writing tool & supply lists. Search CL and eBay for pricing. Make a plan.

FE will fall into place given:

1). All book maintenance to date
2). Careful, planned use. Moving, or stationary.

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I would not "forget the aero" as posted above. A little folding boat tail on the back would net measurable gains. The commercial trucks use them, and they have to fold so as to back to a dock. You don't have to meet that criteria. This simplifies the construction.

Hadn't it been for budget constrains, I'd tell you to try a Cummins R2.8 crate engine. Well, maybe looking out for a more modern replacement engine out of a rolled-over Tacoma?

You hit a lot of threads. OP hasn't posted since 2019-08-05.

Two quarter-circular panels hinged at the rear corners could fold over each other for storage, then swing out to make a boat tail that follows Mair's torpedo-tail. Just have to fill in the top and bottom.