Looking for a fuel efficient solution. I've got a few ideas.

[CuriousOne]

Hello, let me introduce myself/my situation.

My current and only car isn't very fuel efficient (due to what car it is and what I've done to it, but since this is an eco forum I don't really need to tell anyone details) and sometimes I want to work on it so I need another car sometime in the future, but I need this other car to be fuel efficient. The car I'm looking for doesn't have to be luxurious or anything. Just cheap and cheap on gas. Anyways, I'm not really looking for suggestions as I have some in mind.

What I'm looking for are modifications to the car that will be cheap and will give it better fuel efficiency, and I don't want the car to look ridiculous (meaning I don't want to do aero mods to it). Here were my ideas:

Warm Air Intake - I plan to position an open air element filter right on top of the exhaust manifold or very near it so the air is warmest and the air is the least dense.

Gut the interior - I don't really mind what the interior looks like, so I'm just going to gut it. Fairly obvious why I want to do this.

Remove Power Steering - In a light car, P/S isn't really required, so I'll just relieve the crank pulley of weight (for slightly more power) and relieve the car of overall weight.

Remove Air Conditioning - Relieves the car/crank pulley for less weight + more power.

Increase Tire Pressure - It might handle weird, but this will give me slightly better mileage.

Misc. Exhaust Modifications - Most exhaust components are made of cast iron (which is much heavier than steel, stainless steel, etc.), and some are crush bent and just overall very restrictive which creates backpressure. Backpressure in an exhaust system is never needed, so a well tuned combo of a header + exhaust could make the engine not strain itself as much while still giving it more power/torque, while still being an overall lighter system.

Any other ideas, or are the remaining ones expensive to do?

[Bob64]

Why the warm air intake? I know that performance hot-rodders always strive to make their intake as COOL as possible to increase power/mileage.

[CuriousOne]

A warm air intake has less oxygen molecules which means the car will make less power, which means more fuel efficiency. Cold air intakes contain more oxygen molecules since they are denser. As far as I know there's no way to make more power while having better fuel efficiency when you modify your intake, but with an exhaust it is.

[RH77]

Originally Posted by CuriousOne

Hello, let me introduce myself/my situation.

...

Any other ideas, or are the remaining ones expensive to do?

Welcome to EM --

Depending on the model, there are several things to try -- aero improvements, drivetrain tweaks. WAIs work with certain manufacturers -- but nearly all work in colder climate for warming up the vehicle. Depends on where you are, but an Engine Block Heater may help get you started more efficiently. Perhaps some Low Rolling Resistance tires.

Don't rule out the power of technique and instrumentation/feedback.

I assume you've read the EcoModding for Beginners thread...

Best FE to ya!

RH77

[CuriousOne]

Originally Posted by RH77

Welcome to EM --

Depending on the model, there are several things to try -- aero improvements, drivetrain tweaks. WAIs work with certain manufacturers -- but nearly all work in colder climate for warming up the vehicle. Depends on where you are, but an Engine Block Heater may help get you started more efficiently. Perhaps some Low Rolling Resistance tires.

Don't rule out the power of technique and instrumentation/feedback.

I assume you've read the EcoModding for Beginners thread...

Best FE to ya!

RH77

So I guess other than the mods I listed above, the rest are those weird looking aero modifications? Although the drivetrain modification did pass my mind. A lightweight flywheel and lightweight driveshaft would be very useful, along with lightweight rims (not part of the transmission, but reduction of rotational mass is really useful).

About the thread you linked me to, I just read the thread right now and I most of those already.

[Duffman]

My understanding is cold air and cool fuel is best for power and warm air and warm fuel is best for economy. When both are warm the fuel will atomise better. It doesnt matter that the air is less dense when warm, you will just open up the throttle more to get the correct amount of oxygen in.

[CuriousOne]

Originally Posted by Duffman

My understanding is cold air and cool fuel is best for power and warm air and warm fuel is best for economy. When both are warm the fuel will atomise better. It doesnt matter that the air is less dense when warm, you will just open up the throttle more to get the correct amount of oxygen in.

Yeah, I forgot all about the atomization thing, but at WOT Warm vs Cold air, I'd assume the Warm Air is always more fuel efficient since at WOT you can't just open the throttle more and therefore you're just making less power.

Anyways, how about adjustments to timing? Anybody have success with that? The car(s) I'm looking at will most likely be a Honda Integra/Civic/Accord or a Geo Metro (3 cylinder). So anyone with those cars, can you pitch in about that?

[trebuchet03]

Originally Posted by CuriousOne

A warm air intake has less oxygen molecules which means the car will make less power, which means more fuel efficiency. Cold air intakes contain more oxygen molecules since they are denser. As far as I know there's no way to make more power while having better fuel efficiency when you modify your intake, but with an exhaust it is.

The amount of power necessary to maintain a given velocity doesn't change.... What does change is throttle position - you'll need a more open throttle... less pumping losses...

At least, that's the theory...

When both are warm the fuel will atomize better.

Meh, fuel injected engine's don't have anything to atomize fuel - other than the injectors themselves which always spray fuel particles of the same size (ignoring clogs and tolerances due to thermal expansion/contraction). Given the amount of fuel that leaves unburnt (which is less than 1% IIRC) - we're not losing a measurable amount of efficiency because of liquid fuel.... Similarly, if the whole atomization thing were a problem, CNG vehicles would get a whole lot better efficiency compared to liquid fueled vehicles...

the rest are those weird looking aero modifications?

Fixing the "weird" part is easy for someone that's willing to make the modification.... It's not weird, it's efficient A change in attitude/outlook Remember - ordinary economy for an ordinary amount of effort... Extraordinary (but verifiable ) gains for extraordinary amount of effort/work

[RH77]

Originally Posted by CuriousOne

Yeah, I forgot all about the atomization thing, but at WOT Warm vs Cold air, I'd assume the Warm Air is always more fuel efficient since at WOT you can't just open the throttle more and therefore you're just making less power.

Anyways, how about adjustments to timing? Anybody have success with that? The car(s) I'm looking at will most likely be a Honda Integra/Civic/Accord or a Geo Metro (3 cylinder). So anyone with those cars, can you pitch in about that?

It depends on your usage...the smallest vehicle and engine combination is the FE winner. If you need something the size of an Accord, then the 4-cyl, manual is decent. There are other options...

From the Integra standpoint (and personal experience) -- it's heavy and has an engine that likes to make power more than Fuel Economy; however, it's very versatile: fun to drive, fold flat seats + hatchback = cargo capacity, reliability, handling, power when you need it, etc. Make absolutely sure it's a manual if you find one.

The Civic is a good choice -- depends on the year, style, number of miles, etc. Again, the manual transmission is key -- lighter weight models as well.

You can't go wrong with a Metro 3-banger: inspect for rust (owners here can tell you about the specifics).

RH77

[CuriousOne]

Originally Posted by trebuchet03

Fixing the "weird" part is easy for someone that's willing to make the modification.... It's not weird, it's efficient A change in attitude/outlook Remember - ordinary economy for an ordinary amount of effort... Extraordinary (but verifiable ) gains for extraordinary amount of effort/work

Well, I'm not really a hardcore ecomodder. I'm just looking for cheap ways to make a car I plan to buy in the future more fuel efficient, while keeping it stock looking. I don't want to drastically change it's looks. I mean, I could do basic aero mods like removing the antenna, lowering the car, and possible front bumper modifications, but I don't want to do anything more than that.

Thank you for the info though