Want to build a daily hyper miler, help me chose a platform

[El Karacho1647545492]

Prius with an LSX swap. Amidointhisright?

 

Corvette hybrid?

[Lauren]

Doesn't the corvette already get as good if not better mileage then most hybrids

[Green Bastard]

Prius with the all electric conversion (for a shorter commute anyways).

[Draco-REX]

You definitely don't want to make holes in the car anywhere. You'd be better off making panels for the entire bottom side of the car so there's no turbulence or drag beneath.

 

I also wouldn't suggest a lightened flywheel as it's used for momentum... you want all the momentum you can keep in that car when cruising/coasting.

 

I would remove the big mirrors for very very small ones, or really anything outside the car that could cause drag. Cover any possible holes or openings with tape and remove wipers etc.

 

over-inflate your tires and get moon caps. lowering the car will definitely help.

 

Lose all the weight you possibly can in the car.

I agree with most of this but lowering isn't as important for efficiency. Manufacturers have found that getting air to flow smoothly under the car is more efficient than trying to keep it out. So under-panels are the way to go.

 

Right now my plan is a early 2000's civic as the base. Its a very cheep, reliable platform, with easily obtainable parts. The CRX would make a good platform as well, but finding a clean running one is becoming a thing of the past. The VW diesel idea sounds good, but I have a GTI now...and working on VW's are a pain.

 

So, as I sit, my plan is a civic, gutted, skinny tires, with a tune to get the base mpg's.

I'd try to find a small diesel car for your best result. Diesels run lean under light load and therefore use less fuel. A gas engine needs to have a consistent flow of fuel for the air going through it. So a gas engine needs small displacement and/or low revs to get great mileage.

 

A smaller engine ingests less air per rev, and therefore less fuel, but has less torque. Low revs mean less air ingested per mile, but you need a good amount of torque to maintain your speed, and you don't get a low of low-end torque with small displacement.

 

These aren't insurmountable problems, but they are are something to keep in mind.

 

Things I have thought of to try ( NOTE: all of these things are just ideas, yes some are crazy, and some are really expensive)

1. intake/exhaust: we all know it helps with power, but can it help with fuel economy

Yes, making the engine more efficient helps gas mileage. So a high flow intake and exhaust are the way to go. Also, go for manual steering, and ditch A/C if you can stand the heat. If your water pump is external, an electric water pump can help, since most small gas engines rev pretty high on the highway.

 

2. Aero: Tapped seams, wheel covers, lowering, front lips, holes in the bumper, etc. you can go wild with this one. Where does your ROI dip into the negatives?

"Helicopter Tape" and smooth wheels are a good start. As above, concentrate on smoothing the undercarriage over air dams and lowering. Whenever you try to get air to do something it doesn't naturally want to do, you create drag. So help the air flow around the car, rather than trying to force away from certain areas.

 

Also, reduce the amount of air flowing INTO the car as well, as this air will cause drag as it tries to exit. Providing the cleanest pathway you can is a good idea. Go to the minimum amount of radiator opening you can get away with. And try to find low-pressure areas for the air to exit into.

 

"Coefficient of drag" is only half the story when it comes to how well a car moves through the air. The other half is Frontal Area, or how big of a hole the car needs to punch in the air. Minimizing this is important. That's why purpose-built hybrids tend to be narrow. An air dam will increase the frontal area. Small mirrors and narrow tires reduce it.

 

3. Engine: port and polish, forced induction, engine management

Like with #1, efficiency is good. Turbocharging is good for overcoming the lack of power in a small engine, but isn't used for cruising, so it probably isn't worth looking into.

 

4. Trans: lightened flywheel, taller gearing

This depends on what type of driving you want to be optimized for. Think of your driveline as a kinetic "battery". Hitting the gas fills it, hitting the brake empties it.

 

For highway driving you want a big battery so you can store as much energy as possible to help your engine keep your speed steady. And since you're on the highway, you won't be using your brakes much, so you won't have to re-fill the battery. So in this case, a heavy stock flywheel and tall (narrow) and heavy wheels are a good thing.

 

For city driving, and areas with big hills, your kinetic battery can't help you all that much. And since you'll be draining it frequently, you don't want to have to recharge a big battery over and over. In this situation, you want as small of a "battery" as possible. So a lightweight flywheel and small light wheels are the way to go.

 

what would you add to the list? What would you do first?

TL;DR:

Lightest body weight (minimalist interior, excess stuff gone, etc)

Smooth body work

Smooth underbelly

Smallest silhouette from the front (small mirrors, narrow tires, etc)

Smallest air openings in the front

Most efficient engine

Least amount of drag on the engine (small alternator, no A/C, electric water pump)

Heavy or light driveline depending on projected use

 

Crazy ideas:

Locate low-pressure areas on hood and fenders and use them vent air that enters the radiator and wheel wells.

Cameras to replace external mirrors.

Wheelcover "Spats".

Aerodynamic "detachment" methods on the rear of the car (squared body work, shark fins, AeroTabs, etc.)

Rear "diffuser" bodywork. (Use under-car air to fill the void behind the car)

[Doc1647545523]

Please, Draco, stop posting when you're drunk. The guy asked a legit question, so at least put a little thought into your response before posting it.

[Draco-REX]

Please, Draco, stop posting when you're drunk. The guy asked a legit question, so at least put a little thought into your response before posting it.

 

Sorry.. Uhh..

 

Put a LSX in it!

 

Wait.. that's already been said.. Umm..

 

Get an Alpha GT-R instead!

[EssFo]

How about an EV conversion?

 

http://www.evwest.com/catalog/index.php?cPath=40?osCsid=mek5kltm9rum8mld4s48jjfbu6

[Mallard]

"Coefficient of drag" is only half the story when it comes to how well a car moves through the air. The other half is Frontal Area, or how big of a hole the car needs to punch in the air. Minimizing this is important. That's why purpose-built hybrids tend to be narrow. An air dam will increase the frontal area. Small mirrors and narrow tires reduce it.

An air dam doesn't actually increase frontal area since frontal area is calculated from the ground to the roof. Also, my Volt has a very low air dam that scrapes more than Farkas's car.

[Draco-REX]

An air dam doesn't actually increase frontal area since frontal area is calculated from the ground to the roof. Also, my Volt has a very low air dam that scrapes more than Farkas's car.

Frontal area is measured from the car's silhouette.

[Robochan]

http://columbus.craigslist.org/cto/4357149849.html

[buelliganx1]

Well this has 2 wheels not for but it is capable of 470mpg

 

http://www.craigvetter.com/pages/470MPG/high%20mileage%20fairing.html

[Patterson]

Mk3 Golf. 40mpg easy.

[Geeesammy]

Ford Fiesta 1L - 65mpg. Boom done.

http://www.autotrader.com/research/article/car-news/197883/2014-ford-fiesta-with-1-liter-ecoboost-la-auto-show.jsp

 

This, but an older Fiesta.

 

My SL1 after a good tune up and cleaning/adjusting the rear brakes and balancing the tires and putting a perfect alignment on it see's 40+mpg per tank with mixed driving.

[justmyluck]

Draco, awesome ideas. You might have just made the best case to go diesel. Iam still a little conserned about the price to enter the diesel game vs petrol.

 

Essfo, that is awesome. I would be on board for a miata conversion in a heartbeat if I hade a garage.

[vonrottes]

Geo with a small TDI.

 

If Port injection or TBI/carb a Turbo is supposed to help with efficiency since it atomizes the fuel better....or something like that.

 

 

Or just say screw it and buy a Highway scooter, Ninja 250 or other small street bike.

Scooters get like 90mpg highway, my old EX250 got like 45mpg with mods but if I recall there was one guy who was getting 65mpg+ with eco modding.

[Mallard]

Frontal area is measured from the car's silhouette.

 

True. I looked back and saw I was thinking of an example we did in class for estimating the frontal area when limited data was available.

 

However, lowering the ride height does slightly reduce the frontal area by having less tire exposed to underbody flow, and reducing ride height and/or using an air dam can reduce underbody drag. This is why cars with air suspension (Tesla, Jeep Grand Cherokee, etc) reduce their ride height at highway speeds. Tesla even quoted a reduction in range associated with raising the ride height during their fire scare.

 

Also, almost all modern cars are being optimized for aerodynamics due to fuel economy regulations. You'll see most cars have low air dam's in order to limit the flow going underneath the car. The Volt's is pushed to the extreme because they are trying to maximize EV range.

http://static.ed.edmunds-media.com/unversioned/img/long-term/misc/Volt%20front%20end%20lead-thumb-717x477-91996.jpg

 

So an air dam may slightly increase frontal area, but the benefit may outweigh the cost. Obviously, there are other factors that influence this, and it seems that rake angle has a huge effect, so the body should be dropped evenly, if lowered.

 

But I think we're in agreement that the places to focus are:

-radiator's (block unnecessary grill openings),

-underbody (smooth under trays, keep exhaust tucked up tight to the body)

-wheels (wheel wells are huge sources of turbulence)

-side mirrors (as small as possible while staying legal)

[Miller]

I did 39 to 41mpg in the Dart 1.4l. This is from New Albany exit 161 to Tuttle Mall. Not the best drive for gas mileage and I didn't even care about my habits.

 

 

I'd rather drive a Metro tho.

[justmyluck]

Ok so,

Q1 covering up the grill openings. To me, this seems to be a guess and check type of ordeal. Cover everything up and only create openings if engine temp rises?

 

Q2 under body coverings: What would be your go to material for this? Some sort of thin light plastic, but I need some ideas on what kind and how to attach

 

Q3 Wheel wells: Covering the rear wheel wells will be easy, the front wheels raise a challenge because of turns. All I can think of is flat or domed hubcaps.

 

Q4 side mirrors: Does anyone know the law? I would be up for the challenge of custom fiber glassing some small mirrors. I would love to use cameras as replacements, but that is going to be too expensive.

 

Regarding the Air Damn, what are your thoughts on possibly using an aftermarket front lip/body kit ex: http://images.gasgoo.com/MiMwMDRfMDA0IzMxOTgyMjEwMA--/auto-part-honda-civic-body-kits-tuning-accessories-spoilers.jpg

[Mallard]

1. Probably right. You see all the OEM's adding active grill shutters to their vehicles, which open and close on demand. In NASCAR you see teams adding or removing tape.

 

2. Probably thin, light plastic or sheet aluminum. You just have to be careful how much you seal because heat from the exhaust could build up. Start with the problem areas and build from there.

 

3. I agree. You'll also see cars like the Tesla have a small air dam in front of the tire in order to divert air around the wheel well.

 

4. I think you have to have one mirror by law. Camera's are illegal as OE equipment, but not sure about aftermarket.

 

5. Not sure. Some don't actually go much lower, but just stick out. As you see on the Volt, it's just a flexible piece of rubber that sits further back under the bumper.

 

 

For some examples, here are links or pics of the Volt, Cruze Eco, and Dart Aero, all of which have spent extensive time in the wind tunnel to improve MPG. The Cruze and Dart has underbody panels, but the Dart is more extensive. You'll also notice the air dam's behind the leading edge of the bumper and in front of the tire.

 

media.ed.edmunds-media.com/dodge/dart/2013/fe/2013_dodge_dart_det_fe_1241355_600.jpg

 

www.cleanmpg.com/photos/data/506/EcoUnderbellyMed.jpg

 

static.ed.edmunds-media.com/unversioned/img/long-term/misc/volt_underbody_06-thumb-717x477-113345.jpg

Edited April 8, 2014 by Mallard

[Ramsey]

Would covering the rear wells help? what about air splitters for the front wells?

 

As far as exhaust heat, i would just have it cut out just behind the front tire.

 

Could you make bolt-on under body panels for typical hyper-miler cars?

[thorne]

The import tuner article (all 5 parts) was an interesting read, but they spent multiple thousands of dollars to save a few bucks per fill up. Seems pretty silly to me.

Thats what i think to my self everytime I hear of someone doing XYZ mod to get more MPG.

[coltboostin]

Geo metro. 5 speed with the skinniest tires possible. Might as well duct tape all the seams while your at it.

 

I've heard they have diesel 3 cyl metros as well but I've never seen one.

 

Had one. Literally 2 seats, a cluster, and a stearing wheel. I filled up once every 3 weeks, and found a way to get laid IN the car, more than once on Game day.

 

 

Savage mode-ON

 

http://i1003.photobucket.com/albums/af154/coltboostin/DSC02474.jpg

[bdhill]

crx hf...

[6 Speed S4]

Had one. Literally 2 seats, a cluster, and a stearing wheel. I filled up once every 3 weeks, and found a way to get laid IN the car, more than once on Game day.

 

 

Savage mode-ON

 

http://i1003.photobucket.com/albums/af154/coltboostin/DSC02474.jpg

 

Thats awesome! haha!

[BDHG940]

Whatever you decide to do, please do not drive like a fool trying to save an extra fraction of a mpg.