Best way to improve fuel economy?

[TuffGong]

Whew! Don't forget to pull unneccessary seats,carpet,headliner,interior trim,spare tire and jack,replace windows with plexi,smaller lighter lawn tractor battery, only drive with a tailwind,go on a diet.....

Some of the previously mentioned strategies in this thread would fit into this category. Some might take years to "pay back" if ever.

If you can't get satisfactory mileage out of a tercel, it might be time for a 3 cylinder Metro or smaller.

Sorry to seem negative, but this year has worn this topic out beyond belief. Small in-tune roadworthy car and light foot. Any questions?

You can do my mods for pretty darn cheap. If you want to get more indepth, get the manual for $18. I'll let you know when I'm satisfied where I'm at and what my avg. mileage is over the winter. I have a friend who just bought a cherry 300d 75' Benz w/a half working propane system in it. He's currently working on getting it functional.

Cheers

[ARCHINSTL]

Yes a $400 carb does make sense to me as everyone knows how much fun the OE one is,which is also almost $400 from most suppliers. I did it for the driveability. Mileage is a direct byproduct.
(Edit by TFM)

Ditto that ! Exactly the same main reason I did it.
I fought the good fight with the Aisan (three of 'em, in fact), and also did multiple and varied tests of every single emission and fuel system component and spent many $ renewing those parts.
Like all, I was unable to test the ECU itself, as there is simply no information available anywhere on it, and Mother Toy refused to answer any questions about it (Note - I typed "refused" and not "did not answer").

In retrospect, I should have installed the Weber immediately - and saved many $ - and probably some gas as well.
Well, as long as it would have passed the (then) required emissions tests...

Note - again, like splatterdog, I am not dissin' Typrus/takza; they are always full of ideas, which is great!
Tom M.

[takza]

One idea I'll be testing next summer is bubbling air thru a jar of 1 to 1 water and isopropyl alcohol.

What - the air entering the carb is the air of which you speak above? I would have thought the carb's demands would suck the solution as well. Bernoulli was not one of my favorite mentors. Tom M.

Back in the '80s or thereabouts...I used an idea from Mother Earth News to make a bubbler where air was run thru plain water and saw about an 8% gain in mileage...this was with a '76 Corolla and before O2 sensors. all this does is slightly lean out the mix and add a minor amount of moisture. Tried this with the Terc and it didn't work. Iso in the tank does.

The iso bubbler test claim was with a later model EFI vehicle. Might work...might not. Not exactly rocket science to test this. Problem is that the 3AC is very sensitive to added air (vac leak)...it will mess up your idle unless you use the R port that controls the EGR thru the vac modulator. Not talking major air flow here just some bubbles.

You simply run a hose down into the bottom of a pint or qt jar and allow air to bubble thru the water/iso mix. Since this is ported BELOW the butterfly valve...it is added air flow.

The T4WD would be ideal for this? Find one with a bad engine?

http://www.motherearthnews.com/Green-Tr ... c-Car.aspx

[ARCHINSTL]

Interesting link - Thanks!
Mother Earth News used to be a staple here...
Tom M.

[takza]

http://technocrat.net/d/2008/1/7/33233

I'm a little confused about why it's so hard to get good mileage. My 1983 Toyota Tercel SR5 (4WD) wagon was getting 40+ MPG the first couple of years I had it. I had a routine maintenance checkup after a couple of years, and the tech said that fuel mixture was too lean, and at that mixture, it would burn my engine up. He adjusted it to spec, and after that I was only able to make 30+ MPH on highway (25 MPG city driving), but that was still quite good, apparently. This car only had a 4 cyl 1.5L 62HP engine, but it had such good gear ratios that I was nearly always the first car across the intersection.

That was the last time I had the carb serviced. In 2002, at 220,000 miles, I gave the car to a friend (who is still driving it), and it was still making 25mph.

I used to haul 5 adults, or 2 adults and our band's sound equipment, in that car with no problem.

Yeah, it's obvious I wish I still had that car, but if Toyota can make something that great 24 years ago, why can't they now?

[Neu]

http://technocrat.net/d/2008/1/7/33233

Yeah, it's obvious I wish I still had that car, but if Toyota can make something that great 24 years ago, why can't they now?

They can, and they do. Toyota has models that get 30+ mpg, it's the fact most americans WANT POWER over economy most of the time.

When you see commercials nowadays, you hear "325 hp" in that deep tone of a voice, cuz it sounds awesome. They're trying to attract the younger buyers, and younger buyers dont give a crap about fuel economy right now.

Every car manufacturer has models that get 30+ mpg, and it's simple, they all know how to do it. Tiny car, tiny engine. There, done.

[xirdneh]

http://technocrat.net/d/2008/1/7/33233

I'm a little confused about why it's so hard to get good mileage. My 1983 Toyota Tercel SR5 (4WD) wagon was getting 40+ MPG the first couple of years I had it. I had a routine maintenance checkup after a couple of years, and the tech said that fuel mixture was too lean, and at that mixture,
now?

so how do i lean out my carb?

[takza]

Best bet is the carb enhancer manual from Eagle Research? Might try iso.

[Typrus]

Adjust the mix screw in...

Why can't they make them as simple and good of fuel economy as in the days of yore?

Emissions standards.

The new econo-boxes just don't have that air about them. They are just... Boxes. Nothing magical.

BTW, my buddy can get 26mpg (GPS confirmed over the course of 10+ tanks so shut up with the criticism or go complain to your cat or tub of ice cream) in his 1974 Chevelle Malibu Classic 4-door sedan with a slightly warmed up small block 350 and Turbo-HydraMatic 350 transmission. So please, tell me that power and economy are impossible to both grab. Heck, what'll a Viper get on the freeway? 30mpg in real-life? I think thats what the guy who comes into the Zone who has the 3 Vipers was saying... 28-32 freeway? Low 20's city?

I really wish they could make old carbureted beasties. But they just wouldn't be up to snuff for regulations.


I could get into the 40's in my Terc.
Hell, in my folks Passat, I can get 46mpg, shredding tires at every intersection and literally smoking everybody. 46mpg threading the needle on I-25 at 100MPH. Don't tell me power and economy don't sometimes go hand in hand. Yes, its a diesel, but big friggin whoop. It still shows the point.


If you are an economy-crazy person, go buy a Prius and watch me laugh my butt off at you as I outrun you in my 85 3-speed Tercel. Let alone dance circles around you in our Passat and get as good or better fuel economy.

Or go buy an old 1.6L IDI Rabbit 2-door and get it running right and experience the coolness of a very clattery 55mpg. Or, one better, go buy an A4 body style Golf with an ALH TDI and get 60-70mpg freeway at 60mph with the right mods, only to scream well into the triple digit speeds when you do open it up (and still get 40 or better)


But if you want a Tercel, you will need to work for your economy, experiment a bit, and if you so desire, look into a repower. A 1.6L IDI VW diesel would be SICK. NA or turbo. Super-duper simple powerplant with as much or more torque than the terc's 3AC and the ability to till at 5400RPM (redline) if you need to. A little bottom end mods and better springs and say hello to 6k+ revs. And get 40+mpg. Someone with some tenacity could get one to fit, I guarantee it. Absolutely.


Otherwise you look into the world of improving volumetric efficiency, aerodynamics, decreasing parasitic losses, and taking a hit on fun factor potentially by limiting driving. Though I got better economy driving hard.

[Ron B.]

Adjust the mix screw in...

Why can't they make them as simple and good of fuel economy as in the days of yore?

Emissions standards.

....my buddy can get 26mpg (GPS confirmed over the course of 10+ tanks so shut up with the criticism or go complain to your cat or tub of ice cream) in his 1974 Chevelle Malibu Classic 4-door sedan with a slightly warmed up small block 350 and Turbo-HydraMatic 350 transmission. ....Heck, what'll a Viper get on the freeway? 30mpg in real-life? I think that's what the guy who comes into the Zone who has the 3 Vipers was saying... 28-32 freeway? Low 20's city?

I really wish they could make old carbureted beasties. But they just wouldn't be up to snuff for regulations.

I could get into the 40's in my Terc.
Hell, in my folks Passat, I can get 46mpg, shredding tires at every intersection and literally smoking everybody. 46mpg threading the needle on I-25 at 100MPH. Don't tell me power and economy don't sometimes go hand in hand. Yes, its a diesel, but big friggin whoop. It still shows the point.

If you are an economy-crazy person, go buy a Prius and watch me laugh my butt off at you as I outrun you in my 85 3-speed Tercel. Let alone dance circles around you in our Passat and get as good or better fuel economy.

Typrus, I've been around cars since gasoline was under $.30 per gallon and I have been reading Consumers Reports, Car and Driver, Road and Track, Automobile Magazine, Popular Science, Popular Mechanics, Mechanix Illustrated and Hot Rod since the very early 1960's. That makes me an old fart.

Where do I begin? I am having a lot of trouble believing any of your post. Are you serious or are you just kidding around? These are jokes...right?

If not, I would like to see some documented proof of a 1974 Malibu even with a freshly-tuned 307 V-8 getting 26 MPG. Read any road test of that vintage and The Chevy Malibu was lucky to get half that MPG. Remember those were the days of primitive pot metal carburetors, air pumps, low compression and primitive emission controls.

The current EPA mileage numbers for a Dodge Viper are 13 MPH City and 22 Highway. I have never seen a road test where anyone gets more than the EPA highway number.

Check into the real world mileage and performance of Corvettes from the old days. You know, the ones with 4bbl carbs sitting on top of small blocks or big blocks. Compare them to the latest technology on modern small blocks. Today the Corvette is faster in all respects and gets double the miles per gallon. These are FACTS. Check them out.

There is no carburetor-equipped car that will get better mileage than one with EFI. Just about every manufacturer improves their HP and mileage on an annual basis. Modern science and engineering allow for great improvements. Modern engines have roller bearing lifters and rocker arms to reduce shear friction. Pistons are lighter, fuel is metered and injected with high pressure injectors directly into computer designed combustion chambers. In every respect modern engines are vastly superior to those of the past.

Here is a short quiz...

With regards to a modern car, will you save gasoline while coasting with the engine in gear or neutral? Hmmmm

Believe it or not the answer is "in gear." With modern computer controls, the car knows that you are coasting and fuel delivery to the injectors is completely cut off. If you put the transmission into neutral, the engine needs fuel to keep running. With a carburetor-equipped engine coasting causes high vacuum which will waste fuel. So think twice about down-shifting to save the brakes unless you need to.

What makes your Tercel so unique that it will get 40 MPG? Unless you modified it with higher compression, EFI and different cam grind it really sounds impossible.

The published 0-60 times for a Prius are about 10.5 seconds and the published 0-60 times for a 3-speed Tercel are about double that. Even a 5-speed takes 14.5 seconds. What makes yours so quick?

I am not trying to start a "flame war". I just don't like to see falsehoods being perpetrated and having young minds of mush filled with drivel. I may be a "Newbie" but I wasn't born yesterday. I have been around the block a few times. If you look at my current restoration blog you will see that I just might know what I am writing about.

I hope I haven't ruffled too many feathers of those members who have more "Time in Grade" than I do. If I have, I apologize in advance.

Cheers!

Ron B. in Lake George, NY

[sdoan]

FWIW - I think 3 things enhance the fuel economy - good valves, the high gear trans, and - at speeds over 60 mph - a 4ac engine.

I put a 4ac in an '84 last spring and got 40mpg on two different tanks of gas on the same road trip (they might have been back to back but can't remember). This is better gas mileage than I ever got with the '83 with the 3ac. The '83 got high 30's on the hiway on long road trips until I swapped tranys and put in a later model low gear version ('85-'87 w/ new rear pumpkin) then the '83 dropped below 35mpg.

When I went back to a high gear trans and swapped in a 4ac (in my '84) my mileage jumped to 40 on the freeway. But, if I'm not very careful it is lower around town - lower than the 3ac ever was except when the valves were failing. My freeway speed went up with the 4ac too - 60-65mph compared to 55-60 with the 3ac. The reason the 4ac may be giving better mpg is that it is not working as hard at 65mph. Back in the '60s Rootes dropped a 4.7 Liter V-8 in an Alpine roadster in place of 1.7 Liter 4 cyl. (they renamed the car Tiger after their land speed record car of the 1930s) And the road testers found the car got better mpg with the V-8 as long as you were going above 100mph.

Just so you know, I drive the Tercel gentle, I like getting good fuel economy. When I wanna go fast I get on my Guzzi and still get OK fuel economy . (my Bro's got the Tiger )

I would say the early high gear trans improves fuel economy if you drive gentle. I think that you can even drive it pretty fast 65+ and get good fuel economy if you are not sawing up and down on the gas pedal (I seemed to notice something like what Typrus saw but high 30s).

I found the mpg of the '83 Terc 3ac was dropping during the 110,000 miles I drove it and before the engine died it would never get above 30mpg. Finally the engine died (burned valve) and when replace started getting mpg in the high 30s again. I think the condition of the valves (compression) has a lot to do with the loss of mpg.

IMO saving fuel is mostly behavioral. Mechanically it probably goes (assuming the rest is working OK) - valve job first, high gear trans, and then 4ac for freeway and mountain passes.

[Typrus]

Joking about the Chevelle? No. And unless Garmin's GPS system is totally buggered, and the local Shell stations metering device is crapped out, thats what it got. Now, you didn't question how we drove it to get that. Very gentle and no cruise above 55mph. Lol. Holley 4-bbl, Edelbrock Torker II, no idea if anything was done in the lower end as he bought it used, air pump yanked off, ACCEL HEI conversion. Now, I could go and mention how he'd get single digits if he pounded it. But I am talking max here.
Meh. A bit of exaggeration on the Prius and 3-speed slow-tron. That and the other guy was trying to accelerate on ice. LOL... And that friggin 3-speed gets craptastic fuel economy. I want my 6-speed back. Our Excursion gets the same fuel economy as that 3-speed slusher. And would accelerate faster with half its cylinders off. Okay, maybe not half. Lol.

40 is not unheard of highway economy in a Terc. I'm not the only one who has gotten it. I know that much. What made mine special? I dunno. I liked it a lot? Lol. And it was shiny? What are you expecting me to say? I never babied my Terc except on a few runs to try and see if my economy would go up (it didn't) yet it took such good care of me.

Injector duty cycle requested at 0% throttle position indication while in gear decelerating is reduced to 0.0. Requested pulse width 0.0. Why? As you said, it eliminates unneeded fuel consumption, however some engines seem to have a provision to inject small quantities after a certain coasting time (e.g. going over Eisenhauer tunnel and sparing brakes) to keep the engine warm.
For those who haven't heard that they shut off, go ride in a 7.3L Powerstroke and downshift while going down a hill. The engine gets super-quiet, then at a certain RPM starts to stutter back in to the normal noisey operation.

I may not have years under my belt but I am no idiot either.

Go buy a TDI and find out for yourself their sweet economy.


I do not own a Viper. Maybe the guy who comes into my work lies about his economy. Maybe not. But at maybe 75mph in 6th gear on that T-56 and that aerodynamic body, it may not be unrealistic.

Magazines DRIVE the cars they test. I have never seen a magazine reviewer beat EPA numbers. Maybe one somewhere did, but I didn't see it. But I sure as hell know its possible. That is, unless the moon is really a giant textured 100 watt light bulb put up in the sky by the unicorn fairy princess monkeys. And my name is Hong Kong Fuey Number One Super Guy (quicker than the human eye!)


I'd rather have a 67 Split Window than this new Corvette any day. Or a sweet C1. C1, C2, or C3. Heck yes. C4, 5, 6... Not so much. Though I wouldn't turn one down. lol.

Then again, I'm the guy who would prefer a Miura or Countach over a Diablo or Mercielago. Which I probably didn't spell right, but I don't care much for it anyway. But their new 4-door is pretty sweet... Give me a LP5000 Quattrovalvole Anniversario in Anniversario Argento with the Weber carbs.. The MoTronic can bite me... I'll pay someone to keep those sweet babies in tune. And a nice Kreisseug exhaust....


But I wouldn't mind a Fiat Jolly either. Am I odd? Hell yes. Do I make any apologies for that? Nope.


Yeah, the Prius does have the electric motors to help along. Where do electric motors have peak torque? Just off 0 RPM. So sweet acceleration.


Anyone want to talk about solenoid poppet valves with variable lift being incorporated in order to use the infinitely variable settings within the max and min values of lift and duration allowing for essentially infinite cam profiles being built in to allow for peak possible power anywhere in the rev range due to best taking advantage of changes in required line center angle, overlap, duration, lift, retard and/or advance? Thus eliminating the inherent power losses caused by the stress of overcoming valve spring tension and shear forces, not to mention allowing for infinite revs within the capabilities of the oil supply system, rotating assembly, block strength, ability of head to remain seated, max flow in and out of the head, ability to supply fuel, and many other little things to think about. That'd be sweet.
Or maybe lets talk about new transmission technologies like the DSG which utilized a dual clutch setup with dual counter shafts in order to be able to "stage" the next gear so that one might shift gear as fast as the first clutch can disengage and the 2nd engage. Or maybe constant velocity trannies that take maximum advantage of an engines point of peak torque by keeping its revs within a very narrow band then placing them at the point of peak economy while cruising. Maybe lets talk about the difficulty in getting them to handle large amount of power in largely varying climates due to difficulties in changing lubrication viscosities.
Heck, we could talk about all kinds of stuff.

I don't like being essentially called an idiot or a liar. I am not the smartest person in the world, let alone on these forums. I will own that with pride. But I do my best to know what I'm talking about most of the time.

Young minds of mush. What is that supposed to mean. Drivel? Awesome. I guess I spew drivel. Does that make me a young mushy drivel spewer? Guess you better ignore a lot of posts on this forum from the last few years. Pretty much 3000 posts.

I wasn't born yesterday either. But just because it wasn't as many yesterdays as someone else gives them no right to be flipping rude to the younger crowd. I know plenty of mush-brained folks older than myself.


Did I mention my Terc had over 200k miles on the original motor and tranny and that I revved it quite high on a daily basis? And that its compression checked out beautiful on all four holes every time I tried? And that it barely burned oil?

Oh, and it wasn't actually the original engine. My bad. I pulled its engine from my 86 that had a couple tens of thousand more miles on the clock than the 84 at the time of install. Did I mention I did the swap unassisted with no previous knowledge when I was 16 and had never done any kind of serious wrenching to that point? I have essentially either self-taught, come here for help, or hung out with seasoned pros to gain what knowledge I have. No, I am not a Mickey Thompson, tearing down cars at 13 to fix up and sell only to start buying old Model A's to hot rod out.

It just frustrates me when I get belittled like that.


Tucker Torpedo had mechanical fuel injection. Used a helicopter engine for a few of the models. I can tell you that having not watched Tucker.

I can tell you that NASCAR originated from rumrunners.

I can tell you all kinds of useless facts, useful facts, etc. I can tell you about how the murder that started WWI was botched several times before the one to succeed was eating a sandwich in a shop and saw his target's motorcade drive by at which point he proceeded to fire upon the target, his wife, and the other in the car, take his arsenic (or was it cyanide) capsule and try to escape.

I can tell you about how the imfamous Iwo Jima flagraising that everyone thinks of was just a reenactment by the marines hours after the initial flagraising.

Maybe sometimes I get details mixed up. But that isn't the point.
I am not the stereotypical uncaring calloused youth. I believe in things like the concept of freedom and what our country was founded upon, like say the free enterprise system. I have compassion for those suffering.


I am ranting and will now shut up about it.



Anyone want to talk miller cycle versus otto? lol....

[takza]

I got 47 mpg for a full day driving east thru the plains running with a 25 mph tailwind in my Terc. So it's fair chance that good mpg gains on trips might have to do with favorable winds? I also got 52 mpg with my Terc recently due to a pump that shut of early.

[Ron B.]

Gee Typrus or whatever your real name is,

You win. By virtue of your long wordy diatribe, I hereby declare you the expert in all things automotive due to your usage of a massive amount of words. Please don't be so angry.

I will now climb down from my soapbox.

Cheers!

Ron B. in Lake George
2002 Passat 1.8T 5-speed
1988 Fiero GT getting ready for a 3800SC transplant
1965 Ford Econoline 5-window pickup under restoration
http://1965econolinepickup.blogspot.com/
http://sourdoughbakingwithchefboyrb.blogspot.com/
Photos: http://tinyurl.com/RBPhotos
Email: YahooRon(at)roadrunner.com
eBay Member: 64spyderman

[Neu]

I've managed 42mpg twice in my tercel on long desert drives. Usually it's around 30mpg if I'm driving for economy. In the city, where most of the driving is, it's about 28mpg.