Gain 20-80% Mpg Efficiency! Save $ on Gas. See How to Get 41.8mpg!





Introduction: Gain 20-80% Mpg Efficiency! Save $ on Gas. See How to 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!
------- 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?


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**


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!


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!


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!


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


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!  is my effort to share workout advice without making you pay the high personal trainer price! Free gym knowledge and videos! :)



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Please be positive and constructive.




I had a 4 door which I turned into an EV. I believe the EPA highway mileage was 42 mpg so I am surprised you didn't achieve that. The best way to improve gas mileage is not to use any. I drive a Nissan Leaf. My Aspire and some of my EV's.

Great! These all tips are amazing and really helpful to increase mileage and efficiency of my car.

Colder air is more dense. The stock air box does not regulate pressure it simply holds your air filter and has a bug catcher making it safe for your engine. A cold air intake will make your engine have more air to use and run more efficiently. Therefore making a couple more horsepower to pull the same amount of weight. Hemce using less gas for easy acceleration

The part about removing your "(huge plastic piece)" part of the intake, also known as a RESONATOR is an stupid move by underskilled d.i.y. mechanics.

What the resonator actually does in a stock car, is maintain pressure inside the intake, so that the fuel mixture enters the cylinders at a consistent mass flow rate.

Remove the resonator, and you have rough idling, inconsistent RPM's, and loss of fuel efficiency.

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

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 ..

With all the added room in your engine bay, if I were you, I would add a small electrolysis (HHO) system for improved power and efficiency. I just ordered everything necessary to build a nice high voltage electrolysis system using a 12V 8000UF electrolytic capacitor which is hooked up to a switch then to my battery. The capacitor then goes to the 6V-24V 10A adjustable PWM, which then goes to the step up module which increases voltage to 400kV and then goes into my pickle jar with 2 platinum plated titanium mesh plates. The resulting 2 parts Hydrogen 1 part Oxygen combination are then piped into another container partially filled with water to act as a bubbler, then from the bubbler to the air intake resulting in complete combustion which will help over time to clean the engine of all of it's oil and carbon deposits as well as improve both power and efficiency! This entire setup cost me a total of $79.55 Canadian all ordered from ... Minus of course the plastic pop bottle, the pickle jar and both the silicone putty and hosing I had laying around! This is my favourite person of YouTube showing off his water and solar powered tour bus!! It's really cool!!

Did you end up fitting it?