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Hello all, just to give you a little background on myself, my name is Ryan, and I'm a new college student and Mechanical Engineering major and owner of a '99 Saturn SC2 which has gotten me into the world of saving fuel(actually I used to hypermile my Jeep Cherokee but to the affect of only 18-20 mpg, now I get double that)

I'm not sure how the general attitude is on this forum and I somewhat expect to get flamed for being a newbie, but my question to is if you could have your choice of any car to build /extensively modify for fuel economy, what would it be?

This includes any car AND engine/transmission combo. But please try to think on a budget, this would most likely only be a $5000 project. So you can pretty much rule out hybrid engines.

My first thought was getting a Saturn SC1 (sure I'm biased I admit it) and providing aero aids (belly pan, wheels, deflectors), weight reduction, thinner/taller tires, and maybe some slight tuning or engine modifications.

But I'm sure there must be more fuel efficient (for the cheap) platforms out there, so let me know what you guys think!

Preferably it would be something that could at least be made somewhat "cool" and attention getting because my idea is to make this a interdisciplinary project and fundraiser for our college, and be a show car of some odd sort if we happen to set any crazy MPG record. But its all speculation right now, just wanted to get some ideas from some professionals :rolleyes:

Oh and, it doesn't necessarily have to be a car that was fuel efficient to begin with. Shock factor is important. If you have any ideas for a 40 mpg minivan, that would work. If you can think of anything you think WOULD make the right combo, its a possibility.

Some of my ideas were:
Saturn SC1 stock gasoline engine aero aids
Saturn SC1 w/ some diesel swap and aero aids
'90s honda civic aero aids
80s/90s VW Diesel aero aids
'90s dodge neon aero aids

Pontiac Fiero w/ engine swap

Making a much-more-efficient mustang or camaro (engine swap and aero, weight reduction)
Building a higher mileage minivan/suv (not sure about this one)

Also to end I know that most of the difference is in the driver. But I would the end result to be a car that doesn't sacrifice too much creature comfort, and even in the hands of the average driver would yield big MPG increases over the stock vehicle.

I plan on building the exact car I am about to describe;

1) 88-91 CRX (The HF would be best since it is the lightest)
- Fully gut the car except the two seats, driver's side 1/2 of dash board, steering wheel. and pedals.

2) Swap in a d15z1 engine from the 92-95 Honda CX
- This engine is low power, small displacement, vtec-e for fuel economy, and run-lean engine tuning.

3) Use an HF, VX, or CX tranny which have the tallest gearing.

4) Pick up a set of VX rims, which weigh 9lbs each.

5) Make lexan windows to cut down on weight.

6) Do all aero mods possible (belly pan, wheel well covers, wheel deflectors, side mirror removal, all windshield wiper removal, grill blocks, aero front bumper, LRR tires, etc).

7) Run Mobile 1 0w-20 oil.

With that engine in the hatch it came in, it got 55+ mpg for the normal driver. 70-90 mpg for great hypermilers. The CRX should be 500-600lbs lighter. ~2050 lbs for the CX hatch, and ~1400 lbs for the gutted crx.

Get an old car to avoid all the emissions - MG midget weighs 1300 lbs, for example - and throw a little yanmarclone diesel in it.

100mpg Fiat 500 and 130mpg bikes: Heiko's car and bikes (http://www.youtube.com/watch?v=FNpCkKqwD_c)

Heiko is THE MAN!

Ryan: First, Welcome to CleanMPG and you absolutely won't be flamed for being a "newbie." We are all here to learn from one another and your initial post displays that you can be a great asset to "our community."

How does pushing 80 mpg with your Saturn sound? Diamond Larry will reply to your post this evening I'm sure. He has some head mods that he can explain as well as general driving techniques for the Saturn. Look at the new threads from yesterday and you will see that his son got 50 something from a 99 Saturn automatic.

A recommended read for everyone is "Beating the EPA" (http://www.cleanmpg.com/forums/showthread.php?t=1510) from the Home Page. (http://www.cleanmpg.com/cmps_index.php)

Please join in and keep us updated with your successes and failures with your experimenting.

Good Luck!
Mike

Hello all, just to give you a little background on myself, my name is Ryan, and I'm a new college student and Mechanical Engineering major and owner of a '99 Saturn SC2 which has gotten me into the world of saving fuel(actually I used to hypermile my Jeep Cherokee but to the affect of only 18-20 mpg, now I get double that)

Also to end I know that most of the difference is in the driver. But I would the end result to be a car that doesn't sacrifice too much creature comfort, and even in the hands of the average driver would yield big MPG increases over the stock vehicle.

The older cars I'd work with are the early 90's Civic, Geo Metro, and the CRX

On a medium budget: Aero-mod a Ford Fiesta diesel.

On a low budget: Geo Metro, tweak the engine to provide more torque down low, and aero-mod it like hell. It's already a hooptie anyway.

Welcome!

Sorry, I'm not into modding cars, but I'd love to see a van/minivan conversion to PHEV. Getting an older conversion van with a raised roof would provide a heavy platform allowing the use of older/cheaper battery technology. The roof would allow you to have a step up in the rear where you could store the batteries without reducing headroom. From people building their own solar/wind projects, they often purchase used UPS batteries that were originally purposed for cell phone tower power. They are replaced on a regular basis & many still have considerable life left in them when retired, but only cost cents on the dollar compared to new. If I undertook such a project, my main question up front would be, should I use rear electric motors to push and keep the original engine to run the car at higher speeds, as the batteries get hot, and when the batteries are depleted; Or should I design with only electric motors for drive power & then do a smaller engine to provide electricity for charging/driving long range (like the Volt....I hate saying that).

Often students want to do work that can later be turned into a profitable business. In that case, you might want to consider working on mods for common cars that can dramaticly improve mileage for fairly small dollars. I certainly wish somone made a drop in grill cover for my car. The problem here is in the details. Anyone can throw some plastic wrap over their grill & see improvements, but no one offers ready made solutions which get all the details right...1. easy to install; 2. easy to remove; 3. doesn't interact with other system inapropriatly; 4. Has all necessary control (like ability to vent if engine overheats...even better if it can identify the problem & take action without driver input).

Then there are engine mods....I couldn't even beging to talk about that. I know how an ICE works, but have never spent time doing anything but the basic work.

Hope you find your niche & it works out for you and the school.

I like the serial hybrid idea. It might be a bit over the top for budget, but I think it could be done in an inexpensive manner.

The majority of cost for an EV conversion is the batteries. Skip the huge quantity of batteries, put in a smaller ultracap, and run a high efficiency generator when needed.

Hi! Wow thanks for all the great responses so far. I've considered converting a car into a hybrid or electric and thought it would be a good project but I'm not sure if it would be within our budget or capability (for the timeframe at least). But I will certainly keep it in mind.

I'd love to hear about 80 mpg in a Saturn, although I'm trying to refrain from modifing mine too much either for mileage or performance. Thoughts of a better air deflector, and a 5th gear swap from the lower ratio SC1 have been floating through my mind though.

So theres lots of good ideas already, lets keep them coming!

Hi! Wow thanks for all the great responses so far. I've considered converting a car into a hybrid or electric and thought it would be a good project but I'm not sure if it would be within our budget or capability (for the timeframe at least). But I will certainly keep it in mind.

I'd love to hear about 80 mpg in a Saturn, although I'm trying to refrain from modifing mine too much either for mileage or performance. Thoughts of a better air deflector, and a 5th gear swap from the lower ratio SC1 have been floating through my mind though.

So theres lots of good ideas already, lets keep them coming!
Welcome to CleanMPG. Actually, my son quite regularly gets 80 mpg on his way home from work which is ~12.5 miles on country roads. He has even gotten 90+ on that trip before.:eek: His car is a '99 SL2 5-speed. He does P&G as much as possible. The car also has an injector kill switch so all of the miles register when he kills the engine for a FAS. The head mods are probably responsible for some of his high mileage but the significant portion of it comes from his driving technique. If you want to get an idea of what was done to the head, Google "Singh Grooves."

Get an old car to avoid all the emissions - MG midget weighs 1300 lbs, for example - and throw a little yanmarclone diesel in it.

100mpg Fiat 500 and 130mpg bikes: Heiko's car and bikes (http://www.youtube.com/watch?v=FNpCkKqwD_c)

Heiko is THE MAN!

Flatty stole my idea... I'm not partial to yanmar.... There are some small turbo diesels too that might work.

Hmm.. well from looking around a little I'm not a big fan of those Singh grooves. Seems like its something he homebrewed. Theres nothing wrong with that, all the power to him, but all the testing and documentation I can find on it is very subjective, with no really clear back to back tests. Most of the gains people are experiencing could be from the new head gaskets and seals and such they are installing when the rebuild the cylinder heads. Also, although he claims it will help squish I see those grooves as creating areas that will be bound for detonation. After oogling over forced induction engines for a while I know that sharp edges in the combustion chamber are something you like to avoid.

But if you know of some good testing on it, I'd certainly like to see it.

I also don't understand how you people can monitor fuel consumption on such short trips. Just how accurate is the scangauge and how exactly does it work? I'm used to running the tank out, filling up at the same pump, and calculating from the gallons. Somehow I imagine that would have to be more accurate than a scangauge reading for a short trip. :eyebrow:

How exactly would I found out more about "yanmar" clone diesel engines or other small diesels?

Yanmar (http://www.yanmar.com/store/index.asp?DEPARTMENT_ID=39)

Cummins (http://www.everytime.cummins.com/every/everytime.page#)

Northern Tools (http://www.northerntool.com/webapp/wcs/stores/servlet/category_6970_76+85)

Suppliers (http://www.alibaba.com/suppliers/Small_Diesel_Engines/--------1------------------.html)

Hayes Deversified Diesel Motorcycle (http://www.hdtusa.com/models.htm) (not sure where you can get one of those!)

DC alternator Genset with Diesel engine (http://www.polarpowerinc.com/products/generators/7-10kw_lombardine.htm) (looks pretty cool!) Pretty expensive though.

Well I'm thinking it might make a little more impact to design a larger vehicle that is fuel efficient. It's angering me that all the hybrid SUV/trucks GM is offering are still using 6 liter v8s. What is the point in offering a hybrid if you aren't going to downsize the engine.

There's a lack of fuel efficient minivans and larger vehicles in the US. I'm thinking something like a turbodiesel minivan or compact SUV could be a fun project and show people that need large cars for their family they don't need ridiculous technology to get great mileage.

I also don't understand how you people can monitor fuel consumption on such short trips. Just how accurate is the scangauge and how exactly does it work? I'm used to running the tank out, filling up at the same pump, and calculating from the gallons. Somehow I imagine that would have to be more accurate than a scangauge reading for a short trip. :eyebrow:

We may report Mpg based on segments of our total miles driven. The proof of the pudding is still the old fashioned way - miles driven/gallons consumed=Mpg.

Welcome to the site

Diamondlarry is CobraPond's father. CobraPond is our reigning Div A Fuel Economy Champion. Whatever else may be true how they drive that Saturn and what they did to it has worked to increase the car's Mpg.

ScanGuage can have measureable error, but it can also be calibrated by the user to account for that, resulting in tank averages very close to your current method. Thus, we become confident in the trip and day and instantaneous mpg's it reports. From them, we are learning to drive better by changing our behavior.

Welcome. Look forward to your progress with the mods. Search here for basjoos, one of our aero-modder extraordinaires. Basjoos has become a verb, synonimous with aero-mods. His aero-Civic may be the best high speed ride on this site.

The ideal people mover EV conversion would be the Mazda5, since it's small (a bit over 3000lb stock) and available with a manual transmission. Not cheap, of course, but I have seen some MT '06 Mazda5s go for less than $10k recently.

On a more modest budget, I like the idea of taking a 10 year old economy car (Saturn, Corolla, Civic, Protege) and either converting to EV or dropping a little Yanmar diesel into it. Gearing is going to be a problem with the diesel unless you get a HF or VX/CX transmission, but I don't think you can do that because Honda engines spin "backwards" compared to most. Of course you could put the Yanmar into a VW with the tall TDI transmission in it, but that's a much heavier car and beating the TDI's already excellent mileage could be a challenge. But even the TDI is overpowered for most hypermilers, so it may be possible.

For EV conversions, I've become increasingly interested in getting around Chevron/Cobasys' "ban" on large format NiMH batteries. The biggest I know of are 13Ah, which is pretty small. My understanding is the controller and motor capabilities generally limit EVs to around 300V, which gives you less than 4kWh -- enough for a hybrid, but emphatically not enough for a full-on EV.

But what if you used multiple 300V stacks of batteries? You can't connect NiMH packs in parallel, but you could have each 300V stack driving a separate controller and motor. Is it possible to connect the shafts for multiple EV (or forklift) class motors front-to-back so that they ultimately drive a single output shaft? If not, then maybe you could figure out a way to have one motor up front and a separate motor driving each rear wheel. Just brainstorming here.

And yes, this would be very expensive. If you wanted to get >10kWh, pretty much the minimum needed for a reasonable-range EV, you're talking 3x300V stacks. With 24V x 13Ah packs going for $360 at batteryspace.com, that's $13k for batteries and another $1k for chargers (of which you'll need 24). And three controllers ain't gonna be cheap either. But with AC Propulsion charging $60k to convert a Scion xB to a Li-ion based EV, is that so outrageous? NiMH is more safe and more proven. Seriously, some hobbyist with money ought to step up to the plate and show the world this can be done NOW.

Wri, I've been thinking along the same lines. If I had the money I'd already be driving something like what you've described.

Jstol, the logs use only the official odometer miles divided by gallons pumped but for day to day, trip by trip monitoring a SG which is repeatably <1% off from actual in its estimation of the FE over a full tank is indispensable and believably accurate. As for how it works, the gauge measures air flow into the engine. Based upon that, the stoich. air/fuel ratio, and displacement of the engine the gauge calculates the fuel used per unit time. Combined with distance (also provided by the ECU), the gauge calculates the fuel economy of the vehicle. This is why it is important to configure the correct displacement for the engine parameters and to fine tune the distance measurement carefully. Fine tuning the actual fuel use is done at fillup. All of this can make the gauge extremely accurate.

The above is why the gauge cannot correctly measure fuel economy for a lean burn vehicle... the air/fuel mixture is variable but the air flow doesn't reflect the changes. Something like an MPGuino or a SuperMID should be able to track lean burn correctly because they measure injector pulses and distance for a more direct calculation.

go to fueleconomy.gov and check out years 1992-1995 honda civic VX hatchback. I believe that was the most fuel efficient gasoline car I've seen on a budget.

I just graduated with my mechanical engineering degree also, so this would be an extremely productive project for you to undertake. It should be fun and also, don't forget to consult your professors. They're usually very willing to help. You will find most if not all the info you need for FE increase here. If not, then there are links provided. Good luck.

I'll start with a very aerodynamic chassis and a really small but really efficient 4 cylinder engine with lean burn, sized to operate in its most efficient range at highway speeds (55-70 MPH). The transmission would be an automated manual (at least 5 gears optimized for common driving speeds) using a homemade computer and electronics to coordinate shifting. Then I'll add in a modified 3 phase induction motor (coupled to transmission side of clutch) with a homemade inverter and battery pack for regen, boost, and starting. It will operate without an alternator or large 12v battery as a surplus switching power supply and bank of automotive AV capacitors would provide that. A small UPS battery will be used to retain ECU memory when the car is parked. There will be no power steering. The A/C will operate from the high voltage source for higher efficiency (lower losses from higher voltage). There will be a standard 120v plug for charging. The dashboard will be two small widescreen color LCDs side by side so it will be software-defined.

If money is no object, I would use a high efficiency gas turbine engine and a Li-ion hybrid electric drivetrain with an auxiliary hydraulic boost/regen system. And the dashboard controls will include turbine force off (for just before descending a hill) and turbine force on (for building up a high pressure zone behind the car to boost MPG off tailgaters while costing the tailgater some MPGs and pushing them back).

Wri, I've been thinking along the same lines. If I had the money I'd already be driving something like what you've described.

Jstol, the logs use only the official odometer miles divided by gallons pumped but for day to day, trip by trip monitoring a SG which is repeatably >1% off from actual in its estimation of the FE over a full tank is indispensable and believably accurate. As for how it works, the gauge measures air flow into the engine. Based upon that, the stoich. air/fuel ratio, and displacement of the engine the gauge calculates the fuel used per unit time. Combined with distance (also provided by the ECU), the gauge calculates the fuel economy of the vehicle. This is why it is important to configure the correct displacement for the engine parameters and to fine tune the distance measurement carefully. Fine tuning the actual fuel use is done at fillup. All of this can make the gauge extremely accurate.

The above is why the gauge cannot correctly measure fuel economy for a lean burn vehicle... the air/fuel mixture is variable but the air flow doesn't reflect the changes. Something like an MPGuino or a SuperMID should be able to track lean burn correctly because they measure injector pulses and distance for a more direct calculation.

You directed that answer about the logs and the scan gauge to the wrong person. I didn't ask that question. I answered the portion about how FE is calculated.

I also don't understand how you people can monitor fuel consumption on such short trips. Just how accurate is the scangauge and how exactly does it work? I'm used to running the tank out, filling up at the same pump, and calculating from the gallons. Somehow I imagine that would have to be more accurate than a scangauge reading for a short trip. :eyebrow:

We may report Mpg based on segments of our total miles driven. The proof of the pudding is still the old fashioned way - miles driven/gallons consumed=Mpg.


Jstol3, I was responding to the above...

Jstol3, I was responding to the above...

Understood.

go to fueleconomy.gov and check out years 1992-1995 honda civic VX hatchback. I believe that was the most fuel efficient gasoline car I've seen on a budget. Close, but the Honda CRX HF and the Geo Metro XFi scored slightly higher:

1992 Civic VX = 48/55mpg.
1989 CRX HF = 50/56mpg.
1991 Metro XFi = 53/58mpg.

well, had I seen a honda crx hf or a geo metro xfi, then I could have possibly mentioned one of those ;).

The civic vx (1994 or 1995) was about 50/56. I could be wrong, but I do remember city mileage in the 50's.

VX rated mpg was 48/55 for the 1992 and 1993 models, 47/56 for the 1994 and 1995 models. Not hard for a smart driver to get city mileage in the 50s, of course.

FWIW, I briefly owned a '93 VX. I think my experience was atypical, because most other VX owners got mpg well into the 40s driving it hard and 50s babying it, and that's without knowing about hypermiling. But personally, I never could get mine to beat the mpg of the garden-variety Civics I'd owned in the past. Didn't know about hypermiling at the time, but I tried a variety of driving styles and never broke 40 even on highway trips at 60mph. Took it to the dealer a couple of times but they couldn't find anything wrong with it. I suspected it wasn't entering lean-burn mode, but when I said that to the idiots at the stealership they looked at me like I was from Mars. I suspect the aftermarket A/C system had something to do with the poor mileage, but never figured it out. Sold the car after I got clobbered by a Tahoe.

There definitely must have been an issue, possibly related to someone who owned it before you? It could be that couple to a few other things causing the relatively poor mileage results.

Either way, I'd say anyone of those would work pretty well. At that point it really boils down to availability/cost.