Instructables

Gain 20-80% mpg efficiency! Save $ on gas. See how I get 41.8mpg!

video Gain 20-80% mpg efficiency! Save $ on gas. See how I get 41.8mpg!
 
Hello fellow Instructables!

This write-up involves many simple fixes that can help you improve your fuel economy. I was able to get 41.8mpg in my little purple "Eggplant" car! The video shows you the results of my 150+ hours of teaching myself how to turn a cheap car into a Prius!

These particular fixes were used on my 1997 Ford Aspire 5 speed manual. I purchased this car for $900, put about $250 in parts into it, and a LOT of labor. We are talking roughly 150 hours of work/play/fun/stress/learning! (whatever you want to call it)
The full list of repairs and upgrades is at the end of this writeup....

The best way to work on any vehicle if you choose to do so:
- have supervision (safety)
- use proper jacks and jack stands
- have your car repair manual (I use Chiltons and Haynes)
- watch Youtube HOW TO videos on your car make/model/year to get the idea of how to do it!
- HAVE PROPER TOOLS!
------- If you do not have the tools, manuals, know-how, or supervision PLEASE TAKE YOUR CAR TO A PRO!


I list the fuel economy fixes from EASY to HARD below:

EASIEST - Buy a smaller/lighter vehicle
1. Do you really need to drive that 3 ton SUV?


EASY - TIRES

1. check tire pressure (many people NEVER do this)
2. inflate tire pressure to 36PSI  (CAUTION - Check PSI max listed on tire, ensure the max PSI is more than 36! NEVER overinflate tires)  **This step will cause less rolling resistance**


EASY - WEIGHT REDUCTION

1. Assuming you drive local and have GOOD tires on your car, you can lose the jack and spare tire. These combined probably weight roughly 40-60 pounds (varies per vehicle)
1A. Remove your rear seat (if you have a vehicle that will allow this)
2. Less weight = less gas required to move your vehicle.
3. CAUTION: I only suggest you perform this step if you trust your tires and/or have a AAA Car Club or some kind of tow/repair service membership!


EASY - CHANGE AIR FILTER

1. pop hood, undo 2-4 metal snaps, replace your old dirty air filter!
2. Simple! your engine can breath better! (think how nasty your home furnce filters get; same thing happens in cars)


EASY - Oil change (Professional at work shop)

1. $25-35 saves a LOT of money when you engine parts are well lubricated


EASY but costly - ALLIGNMENT (Professional work at shop)

1. Having your car properly alligned can make your car travel straight.
2. Straight driving causes less wear and tear on the tires and makes for a smoother ride!

Are you ready to get your hands dirty? If not, do NOT go past this section!
If so, pop that hood and lets go!


MEDIUM - EXTRA AIR INTAKE (aka "DIY ghetto cold air intake")

1. I have no clue if this helped, but it seemed to allow more air into the engine.
2. Remove factory air filter box (huge plastic piece)
3. Purchase flexible aluminum ducting
4. Use aluminum ducting to create an air flow from the front of your car to the air intake tube, bypassing the filter
5. CAUTION: Place some sort of filtration system in the air intake tube so loose deposits do not make their way into the engine!


MEDIUM - CLEAN THROTTLE BODY

1. The throttle body will get dirty on many cars. This happens with carbon deposits.
2. A dirty throtlle body will allow less airflow and can restrict engine performance.
3. Cleaning the throttle body involves removing the air filter box and the air tube that connects to the engine. (you may have to remove 1 or 2 wire attachments)
4. After you remove these tubes (normally plastic) you can use "throttle body cleaner" spray to clean the black gunk off of your engine. Be careful to not use too much as this can choke up the engine!


MEDIUM - Replace SPARK PLUGS and WIRES and DISTRIBUTOR CAP

1. This part requires proper tools (spark plug socket, wrenches, etc)
2. 4 cylinder engines are easier to work on compared to 6 cylinder engines.
3. If you do not have the tools or are not sure what you are doing, pay a professional.
4. Chaning the spark plugs and wires will require patience, but is not difficult with the right tools.
5. This will allow for better/faster ignition in the cylinders and possibly more efficient fuel consumption


MEDIUM - FUEL FILTER REPLACEMENT - (Professional at shop)

1. Gas is dangerous!!!!
2. I suggest you have a pro do this step.
3. You can do it, as I did on my car, but you need a repair manual (like Haynes) to make that happen


HARD - GUT ENTIRE AC SYSTEM WEIGHT REDUCTION!

1. Buy a metal grinder
2. Find all AC pipes, cut them with the grinder (wear goggles)
3. Remove the AC cooling fan and condensor
4. Wow look at all of that room in the engine bay!

Hopefully you were able to upgrade a few of your systems :) Now enjoy the savings at the pump!

The full list of fixes include:
- removed spare tire and jack
- removed rear seat
- removed A/C system and all components
- removed rear seat belts
- removed winshield washer fluid container
- removed excess plastic from air intake (it was restricting air flow)
- added a "DIY air tube" from front bumper to air intake
- new spark plugs, wires, and distributor cap
- new O2 sensor (front)
- new fuel filter
- coolant flush
- new valve cover gasket
- cleaned the heck out of the THROTTLE BODY and INTAKE (using carb cleaner)
- inflated all tires to 37psi (less rolling resistance)
- replaced both tie rod ends
- removed the carpet and installed new carpet

With all of this work, I removed somewhere around 130 pounds of weight from the vehicle. Also, upgrading and replacing many of the (engine/exhaust) systems probably helped increase the fuel economy.


If you like saving money on gas and fuel economy improvements, my website below will help you save $1,000's at the gym!
 www.FitnessPatterns.com  is my effort to share workout advice without making you pay the high personal trainer price! Free gym knowledge and videos! :)



NRG4UandMe7 days ago

on my prius, adding the EV MODE button (that only shipped to euro and not to us on gen 2 models) gave me an additional 5mpg .. i could shut the engine off as i roll to a stop (esp in first 5 min of warm up) and if only going short distance .. keep in ev mode so as not to even turn on engine ..

NRG4UandMe7 days ago

ihave a hybrid .. k&n air filter improves flow, but sucking in cold air , as we know an engine isnt efficient until the water gets to ~ 180F -- sucking dense cold air, yes great for the drag strip, but if u want economy, try saving and reusing as much heat as possible, in cold climates, people suck the hot air off the EX manifold sos u the winter cold temps dotn kill the mpg's .. another thing ididtn see was FULL Synthetic engine (and tranny) oil .. changing your motor oil from reg, to semi-synth, and then to full mobil one synthetic oil lets u go 5000 or more miles before changing and reduces internal engine friction, u can get 1--5% mpg from that, the downside on the synth, its more costly AND u have to stick with it, u cant go back to dyno oil once on full synth .. that is juts my experience with cars of in the past .. the engine gets used to full synth and the parts work with it and without the lower friction lubricant they seem to wear much faster ..

NRG4UandMe7 days ago

'fuel saver' or 'gassaver' tires by goodyear (i think) they can inflate to 50psi , they have special 'low rolling resistance rubber' -- u can really feel your car 'roll' instead of 'drag' -- i have found if u do what the tire shop does (32-34psi) the tread wears real fast but at 40 -42psi the wear on the rubber is greatly reduced

brent_hxc3 months ago

okay a cold air intake hurts your mpg.
take the hose off and cutt open that air box for some more air flow that
lets you have less pumping losses

dont take your spare tire out just yesterday there was a woman in the shop that didnt have one and she really needed it

and lastly the max psi on most passanger tires is 44 psi i run my tires at 40psi on my truck

ironsmiter1 year ago
From 26(combined)NEW to 42@15 years old is IMPRESSIVE.
have you gotten yourself signed up and active on ecomodder.com yet?

tire pressure : for best mpg inflate to max psi on the tire sidewall(36 is NOT a SET number, and unless you are running the tires that came with the car when new, ignore the door sticker.) Note that this will make your ride a little less cushy and traction in extreme conditions may suffer a bit.

Weight reduction : expect around 1% improvement in fuel economy for every 100 pounds of weight removed. Triple A and a can of fix-a-flat are a LOT lighter than a full sized spare, and all the tire changing tools. CLEANING OUT YOUR JUNK can make a big difference too. open up that trunk and look at all the stuff you're hauling around for no reason. That's all gas you could be saving.
I don't know the exact weight of components, but you may find that removing the passenger seat to be a better option than the rear seat. They tend to be heavier, and you only reduce your available passenger count by one, instead of 2(possibly 3 on some models). It also has the added benefit of having your extra grocery storage space RIGHT THERE, eliminating "shotgun" arguments among younger passengers, YOU and you alone can control the radio, and there is never any side-seat driving.
The downside being possible spousal disapproval. But at that point, you're probably driving a minivan anyhow :-(

Alignment : You CAN do it at home, yourself! try this out. http://www.hotrod.com/techarticles/chassis/hrdp_0411_wheel_alignment_guide/viewall.html and ignore all the stuff about weight scales and such. for the cost of the kit, you can buy a LOT of fuel. the trade off here is just not worth it, unless you know a college or high-school nearby with an automotive/racing program.

Cold-air intake : This will NOT help your fuel mileage(and may actually HURT it a little) but what it WILL do is increase the POWER. The extra power MAY allow you to change your driving habits a bit, for better mileage however :-)

AC removal : well THIS is a can of worms if ever there was one. FIRST things first, if you plan on pulling your AC completely, get to a garage, and have the refrigerant removed. even the new stuff isn't good for the environment(thought it's supposed to be better). Second, if the system is working before removal, you can carefully remove it, and SELL IT complete. that's more cash for your fuel tank!
Now, in a 97, you may be able to just pop off the compressor and belt, but then again, maybe not. Others may find the need to install an idler pulley to keep the belt properly tensioned now that the AC is out-of-the-loop. it will be a case-by-case experience. Also realize that you have seriously degraded the resale value of your car. Not a big deal in the case of the OP, but consider the cost before hacking away at a car you may want to sell in the future. You MAY be able to just remove the belt from the compressor, and leave the AC intact. You don't shed the weight, but you still eliminate all the drag on the engine, which is good for about 70% of the gains made by a complete strip. Also, doublecheck that it's ONLY the AC that is being cooled by that fan. There can also be oil coolers, air coolers(for turbos or superchargers) and even transmission coolers, that all LOOK like the AC condensor, or may even be hiding behind or in front of it.
I've worked on the 96 version of your car, so a bit of specific advise. Grab a piece of chloroplast, or similar durable sheet plastic, and cover the part of the grill where the AC condenser USED to be. There will be a slight improvement in aerodynamics, and your radiator will work better.
edit: just rewatched the video... looks like you already DID grill blocking :-) just didn't list it above.

EBSAS : Error between steering and Seat. The final leg of the journey into maximum fuel economy. Learn to drive differently. Depending on your modifications, and original vehicular specs, your driving habits can easily count for 10% of your fuel economy. Driving the straight gas car, I can usually get 10-15% better mpg than my co-drivers. The new escape-hybrid...not so much. maybe only 5% different at most. The engine-off at stop feature takes a large bite out of the advantages of most economy driving techniques. Specifically things like shifting into neutral, and coasting to lights, and engine-off when sitting for more than 30 seconds at a light or train. The hybrid does all that automagically. and has regenerative breaking to kill the advantage of another handful of driving techniques. Then it goes and adds in a CVT, taking out most of the advantage of a stick shift as well.
All in all, 32MPG AVERAGE for a fairly good sized SUV is, I think, pretty darn good(highest ever was 40.8 when almost brand new, on a longish highway run in the spring). Not bad, compared to my 96 geo metro(3cyl, 1L, 5speed stick. no AC from the factory) which manages 46MPG, but at the cost of creature comfort and some functionality. Now, If only I had the time and skill to hit that golden mark of 60MPG@60MPH for 60 miles or more.
TheGeniusCreates (author)  ironsmiter1 year ago
Thank you for the informative and detailed response!
I learned most of my information from ecomodder.com :)
I think some of the things I did such as the AC removal and air intake tube were more "playing around" because the car was so cheap. I looked at it like this: The car cost $900. The worst thing that can happen is I break it! I would much rather do it on this cheaper car and learn/teach myself opposed to a newer car!

I was unaware about the AC at a shop, let alone reselling the parts. Sadly, I threw everything away :( But your helpful tip shows me I need to be more careful AND hold on to some of those valuable components!

That car alignment link looks pretty intense. That is one of those things I would pay the $80-$100 to not have to spend all the time on minute details. Odd as it may seem, I will spend 10 hours on a cv axle, but want nothing to do with the alignment! Thank you for the suggestion!

I agree with you all the way about everything, specifically the DRIVER driving style. I make it a point to NEVER floor the gas pedal (unless death is looking me in the eyes). I also use slow acceleration, nuetral coasting, and light braking when possible.

I considered turning the car off at red lights but figure that would only put 2x the strain on my starter. I doubt saving 3 minutes of idling will be worth having to replace my starter sooner. Not sure oh this though?

You have done quite well with your SUV! 30+ is INSANE for an SUV :) Great work! Keep on it with your Metro. You can get that 60mpg! Try rear wheel dams, a front air dam, an underbody skirt, and maybe even a boat tail? As you know, ecomodder loves these things!
The Geo, after some rust repair, MAY be getting "golf ball aero modding"
Like you, I won't feel the least little guilt in modding it. It was purchased over 3 years ago for a miserly $650. and so far, less than $100 in maintenance.
So far, it's gotten a cold/warm air intake(CAI is REMOVED during the winter, to pull in warm engine air, for quicker warmup and better mpg), grill blocking, and seat removal.

After watching one specific instance of mythbusters, where they ADDED weight, and STILL got over 10% better mpgs.(http://dsc.discovery.com/tv-shows/mythbusters/videos/dimpled-car-minimyth.htm)
well, I just don't think I'll be able to leave that one alone.

So, the plan is to plasma out dimples holes, use a hydraulic press to stamp out some dimples, and weld them back in place. Unfortunately, it will take quite a while to do all the welding, so the before and after runs may be spaced too far apart to get any accurate measurements, but at a theoretical 10%, It should definitely be measurable. Given a 10 gallon fuel tank, and over 45MPG, it SHOULD make an immediately noticeable difference.

As for the Escape... well, it's STICKER mpg is 31/34... so we're merely doing OK. Still, it's a pretty nice ride, and good on gas.
TheGeniusCreates (author)  ironsmiter1 year ago
ironsmiter,

Mythbusters is an awesome source of knowledge!
I am impressed that you know how to weld! That is a skill that would be awesome to learn! I looked at the cheap welders from $100-250 @ Harbor Freight and was VERY tempted....

Sounds like the effort might not be worth the results on the Geo! That is your call though :)

On a completely unrelated note: Have you ever watched the videos at TED.com? That is another great source for knowledge, somewhat similar to the type of things Mythbusters covers but more of an academic stance/lecture format. I highly suggest it to you!
- Justin S.
not worth it cause the geo's old and rusty? or "not worth it" because of it's already high fuel mileage? One thing that makes me think the geo might benefit even more is, it's aero characteristics. the funny shape(mine is the hatchback) means that the smooth airflow and 'stickiness' are ... well, NOT good. Just imho.

Personally, I think it's MORE worth doing, as the MPGs get higher.
If the ford pickup goes from 20 to 22 MPG, all your work gained you 2 miles per gallon of fuel.
That same percentage increase on my Geo could net me 5 miles per gallon.

Now, just to crunch some numbers, at 5 miles per gallon, on a 11 point something fuel tank, that's 55 miles per fill-up FREE. and at near to 50MPG, that's basically a free gallon of gas for every tank!


On that completely unrelated note, YES I have watched a number of TED's videos.
One of my favorite TV people did a talk for them. Roy Underhill! I absolutely LOVED watching a room full of nerds, geeks, and business type people listening intently to the guy up on stage SWINGING AN AXE. I have seen a couple other talks, but my attention span is too short for some of them. I am of the age where, due to my childhood training, all lectures should come with commercial breaks AT LEAST every half hour. Talk about global warming, show me a dancing monkey, expound on how to limit global warming, Sell me sugar cereal throw in a 5 min roadrunner cartoon, THEN start into how to fix the damage already done.
Peter Jackson had it right, I think. EPIC ALE of middle earth, and right in the middle [intermission] the likes of which haven't been seen since Monty python was still a bunch of young British guys larking about in front of a camera.
notjoe91 year ago
Hmm I was going to try the golf ball thing with a ball peen hammer as the past hailstorm has naturally begun the process :O
TheGeniusCreates (author)  notjoe91 year ago
I think they tried something like that on MythBusters. Go for it! Call it a "custom" body work! :)