Gollum, I don't really know how you can say that increased efficiency doesn't neccisarily mean increased FE. Yes, I guess I can understand if you had a very lead footed driver or if the only way to get the increased efficiency was to operate some absurdly large engine that used more fuel to begin with.

But what we're talking about is the same exact engine only with increased volumetric and thermal efficiency. I understand your point that it's going to use more fuel just as a larger discplacement car would, but even if it uses the same amount of fuel as a 3L V6, if it's more efficient it will be putting out either more energy or using less fuel (that's the definition of efficiency).

Of course a 3L uses more than a 1.5L which is the point in proposing a 1L with a turbo that's more efficient that a 2L NA with similar power but with better FE.


No electric involved, just plain old TDI: https://www.vwvortex.com/artman/publi...nter_319.shtml

I've got disagree with you here. If engine heat can be equated to wasted fuel energy (which it can), then increased thermal efficiency will mean that you're extracting more energy per lb of fuel burned and converting it to mechanical energy. Wether you use that to accelerate faster, or cruise a greater distance at low throttle openings is primarily up to the driver. Engine design can also affect this but for a given combination, you have a lot of choices (The force is within you.... you must use it wisely...;) )

What IS true is that a turbo may only increase the thermal efficiency of the engine at certain rpm/throttle openings. The goal is to get the increases in the area where they will be most useful for FE fans. That's a different goal than HP fans.

On another (although similar) note, I've had an idea rattling around in my head for years now.... It's for a true tunnel ram intake that might produce a small amount of positive pressure at highway speeds. It would have to incorporate a turbo style BOV to avoid pressure waves, and would need a long straight stretch to work (my original idea was for a rear-engined VW), but it would probably have the same effect on the highway as a Low pressure turbo would.... If there are any VW owners around who want to do some fabrication, I'll be happy to share my thoughts.

Oh but the arena of engine power and how it relates to thermodynamics is complex!

For the sake of simplistic aregument, I'm going to use made up numbers to illistrate my point.

Say your air intake temp is at 90 degrees, and the exhaust temp is at 900 degrees and you're actually making 50hp. If we lower the intake temp to 70 degree, all other things being equal, we're now making MORE power.

If we raise the compression and the exhaust temp goes up to 950, we've now INCEASED power.

If we reduce the fuel and lean the engine out it's now making LESS power but it's raised the exhaust temp.

All of these change the thermal efficiency of the engine. So you see power and efficiency aren't always related to the temperature different of intake and exhaust.

A turbo is said to make an engine more thermodynamically efficient because it's converting heat to power, making use of the temperatures the engine is already creating. It will raise the exhaust temps considerably, but it raises the power MORE susbstantially, hence the increase in power.

What this is really doing is increasing the VE of the engine. Naturally aspirated engines are lucky to reach 95% from the factory, while naturally aspirated engines are doing something wrong if they can't hit 110% from the factory.

Wasted fuel energy DOES equate to heat in the exhaust, but there's many other factors that equare to heat changes of the engine both on the intake and exhaust. A turbo modifies both, and helps the engine become more efficient under load, hence extra power.

If a turbo trully improved wasted fuel energy THAT much (which is almost strictly about chamber temps, timing, compression, mixture, and quence) then it would see a DRAMATIC fuel efficiency increase... which I've never seen with documentation to prove it. The dramatice thermal dynamic improvements turbos are giving an engine result in an increase in air for the given volume and heat being generated, thus more fuel. If you can get the turbo to increase air volume without creating too much heat you WILL truly see a slight improvement of wasted heat energy, but it's because of the air temp/air volume ratio more than anything else.

I've thought about the ram air idea too. It definately has been known to add a couple HP to racing motorcycles, at the HP they were running it was about 5% increase and only from a fairly quick speed.

I'm sure I could look up the equations, but what kind of pressure could you really expect to see at 55MPH as most of us go. I agree it might help offset the losses associated with going at an increased speed a little, like if you got 65MPH you'll get 4x increase of pressure on the front of your car so now you'll have a bit more boost to your intake, but overall I'd be a loss.

Of course you could always completely seal the entire engine bay off and get a gigantic radiator openning and then all air would have to either be forced into the engine or slow you down as drag. Actually now that I think about that, the more pressure you have from a RAM intake setup the more drag you neccissarily have to be inducing on your car. The drag of course is worse for a giant radiator hole than for a small intake hole (based on openning area). Also would a smaller openning be better because of less drag, or would a larger openning that tappers waaay down to a small intake be better because it increased intake PSI?

Regular classic ram air intakes like the shaker hoods on mustangs have been known to get as much as 3psi when going fast enough. At highway speeds .5 psi might be more reasonable. Still enough for a gain in efficiency if the fuel is still atomizing well enough.

darn you, you just reminded me I still have to experiment with 3 cycle engines using direct water injection. I thought I was making progress on my list of stuff to test but now I have to add that one.

Doing some map calculations, looks like a T04E 46 trim would get me to about a 2000rpm minimum boost.... Those are cheap enough turbos. Maybe I'll find one and rebuild it for experimentaing sake. Should support my engine up to about 325 hp too, about what I'm shooting for anyways (don't plane on going over 300 crank/250 wheel HP).

It all kinda hinges on the job situation though. I'm about to be in limbo between old and new jobs next week... and I don't have a new job yet. This is what happens when you go back to school. Grrr.

Oh, water injection... Yea. I want to do that eventually once I get megasquirt up and running. Has some amazing possabilities for power AND economy.

Now that we can agree on! But for all the complexity you want to quote, efficiency is efficiency. A net improvement in efficiency of an engine (after taking all the interactions into account) will yield a net increase in the amount of fuel energy converted to mechanical motion. You're not going to get an improvement in efficiency and a decrease in the amount of energy extracted... period. You can't argue that a turbo increases the efficiency of the engine on one hand, then claim that you're wasting as much or more energy than before on the other.... Now it's just a matter of using that increase in a judicious manner.

I don't necessarily agree with your percentages (they seem awfully optimistic to me, but it really doesn't matter for the discussion at hand) but I'd argue that an improvement in the VE of an engine can be translated into better Fuel effiency. In a global sense, the increased power output of engines over the past generation has allowed greater hp from smaller engines than ever before. Those increases are the direct result of increased VE. I dare you to compare the fuel efficiency of a 175 hp V8 from 1988 and a 175 hp 4 cylinder from 2008. I haven't done such a comparison myself, but I'd bet my house that the new 4 cyl has better FE..... Granted, it's not exactly apples to apples, but it demonstrates the point. You can see similar changes through generational changes in small engines. Look at VVT vs non-VVT engines of the same type (D series Honda, or Nissan K series for example) and I bet you'll find a similar result.

Nobody ever claimed that the improvement was dramatic. I believe that a few percent improvement is what we've been talking about. Couple that with the fact that people who buy turbo cars or add turbochargers themselves want more useable power and drive more aggressively.... Do you really expect to find documentation to prove it? I think that it'll be up to people like us to provide that documentation.

The VE figures I mention aren't based on the power potential of fuel. On that rating systems engines are lucky to ever reach 30% That's where fuel efficiency comes from honestly. How much power is it making for a given air volume?

The VE I'm talking about is the same VE rating you'd use to turn a MAP based ECU or see in a Dyno simulation software. IIRC 100% is 100 pounds of torque for every liter of displacement. This is what a turbo is REALLY doing, it's increasing the ability of the engine to make power in relation to it's displacement. It's not making the actual combustion more efficient. That's the REALL efficiency improvement people talk about in regards to adding a turbo. Sure, there might be a small percentage of combustion improvement, but it's small like we both agree on. Worth spending the time on? Maybe. Worth talking to everyone about? I don't think so. Worth dabating about? Hell yes.

If we don't sit here and argue back and forth it's unlikely and testing will be done, and if anyone goes into testing this too optimisted, the real results might be lost in a cloud of dissapointment.


Oh, and I bet a 175hp V8 from the 60's is a lot less efficient than a 175hp modern 4 cylinder... but apples and oranges man. Let's compare a pushrod 4 cylinder engine from the 60's, or the DOHC V8 ford made in the 60's. That's a bit more apples to apples.

Most of the economy improvements over the last 50 years hasn't come from any single factor. Less friction coatings, lighter allows, computer controlled fuel and ignition, and chamber shape are all huge factors.

For a comparison, people were getting over 1000hp out of the Nissan L engine back in the 80's. People are considered lucky nodays to get 800hp out of them. Why? All the research that was done on reshaping the combustion chamber and ports has been lost. Those people have moved onto working with other engines. Even on the most modern engines, 1000hp out of 3 liters is impressive. Even that old SOHC Datsun engine could make some increadible power. It comes down to many other factors than just how many valves you have, and how many amazing technologies your engine employs.

Oh, I was just thinking about something... On top gear, at the begining of the new season Jeremy did a test. He followed a prius around a track following in a BMW M3. The prius was driven all out, and Jeremy just had to keep up in the BMW.

The BMW averaged 2mpg higher than the Prius.

Why so??? The BMW is more in it's range off efficency being pushed that hard. While the prius was going well beyond it's peak torque to squeeze out the most HP possible, the BMW was just reaching peak torque, and just loafing along easily for that engine.

MPG is about so much more than how efficient an engine is.

As I stated earlier in this thread. The only way I could see a turbo having a significant improvement on FE would be if it's actually IN it's efficiency range while at cruising speeds, which doesn't leave much room if you actually put your foot into it. The turbo will reach the end of it's efficiency and overspool badly. Is it possible to really find a balance? It's worth experimenting with.

Remember that the range of efficiency is increased when a turbo is applying boost. The torque curve flattens out quite a bit meaning the engine can revv higher and still be reaching good efficiency.

Torque is a direct measure of engine efficiency.

Yes, but you can increase torque by imrpoving combustion quality, or the amount of air/fuel. By porting a head and changing a cam you can increase torque and HP, but have exactly the same HP per cubic foot of air.

For fuel efficiency you want to make LOTS of power with as little AIR as possible. It's completely different than just looking for more torque or power.

Turbo and or supercharged, allows you to use a smaller engine for the same weight vehicle. My project is a 71 karmann Ghia with a 1 liter Yanmar diesel engine. I may add one of the stock turbos from a Nissan 300 twin turbo for better power (the turbo would be free). That way I should have decent performance and exceptional mileage.

regards
gary

Yes, that is true, but most efficiency is lost because of the relatively cold chamber walls and cylinder absorbing a lot of heat.

When you are at part throttle you lose A LOT of energy this way and is one of the reasons why engines are more efficient the more throttle you are giving it. The turbocharger or supercharger is giving you more efficiency under boost for the same reason. The percentage of heat lost to the engine itself is less because the ratio of volume to 'heat sink' area is more.

Think of it like your ac in the car. On low, even on the hottest of days you can get cold air, it might not mean much because the ambient temp is so high but it is cold. If you turn the ac up(open the throttle more) the evaporator(engine block) can't absorb as much heat from the air(the burnt fuel in the cylinder) so you have more air(power) even though(because) the temperature difference between the ac inlet(fuel burning in the cylinder) and the vent to your face(spent air/fuel exiting the cylinder) is less than when the ac is on low(part throttle).

oOo, but here's the clincher... is it that the cylinder walls are cold, or that the chamber is too hot?...

Most engine designs that remove the poppet valve can run upwards of 13:1 compression ratio EASILY due to more even temperatures that don't exhibit severe hotspots.

Those engines see HUGE improvements off efficiency for every molecule of air and fuel put into the engine. Some engines have even seen 16:1 compression on regular pump gas. That's increadible! And that's also far more gain in efficiency than any turbo will give you. If your goal is maximum mileage, you shuold be trying to figure out how to LOWER temps inside the engine, not raise them. This is why water injection can improve mileage. It allows you to keep the chamber colder, and run higher compression, more timing, leaner fuel mixture, of a combination of any of these.

Making an engine hotter or colder on the intake/chamber/or exhaust can be a good or bad thing depending on what's doing it, and what you're doing to take advantage of it.

EDIT: Something else to consider, is that turbos are usually less efficient (take more gas) at a given HP level than natural aspiration when driven under full engine load. Why? The turbo heats up the intake temp, meaning you can't run as advanced of timing, and you have to richen the mixture slightly to keep the cylidner slightly cooler. I'm worried running even mild boost while cruising might consitute similar precautiosn negating any gain.

Tell you guys what. I'll move my turbo build forward and get started right away if you want to put a collection together and source the parts for me:rolleyes: I'll do the fabrication, labor, and data collection. I figure I can DIY it for under $500 and just my time.

In a roundabout way, I think you just made my point for me. I picked engines made in different decades to compare the level of technology and the creeping improvements in engine design. Similar power, similar torque, less fuel consumed... All through improvements in design (yes, combustion chamber, valvetrain, fuel injection, better materials, etc.) that yield a more efficient engine and extract more power per unit of fuel. The problem is that up to now, Americans (unlike people in many other countries) don't want smaller more efficient engines, they want faster more powerful cars, so that's where the technology is going. The same technology can be used for FE instead of HP though...

Gah, I really dislike these blanket assumptions about SMALLER being inherently BETTER.

I suppose if you had two identical engines but one was 70% the size of the other, it would get better gas mileage, as long as the loads they saw where the same in proportion to the engine size.

BUT, if you take the two engines and put them in the same car going 80mph, where the wind is starting to create quite a load, I bet fuel efficiency will be nearly identical. The smaller engine, though uses less fuel overall, will be needing a larger percent of it's power to keep the car at that speed.

Fact of the matter is that's not so much about engine size as engine technology, hence why I said if we wanted to compare a DOHC V8 from the 60's that it'd be more comparable.

Smaller engines aren't usually MORE efficient than a larger engine built to the same specs. But they're usually in SMALLER vehicles, and due to having less omph people aren't driving as fast or agressive as they would be otherwise.


On my commute this morning I was thinking though, that we could consider the ERG a good counter comparison to a turbo. A turbo is raises efficiency to gain HP, but only under higher load conditions, while and EGR can imrpove efficiency to gain FE, but only under low load conditions. Both alter the temperatures seen by the engine, and guess what? The EGR is more proven as a FE device, and it's COOLING exhaust temps, not raising them...

Yeah, smaller isn't always better.

People use 454 Chevrolet engines for irrigation pumps because under the loads they see you can't beat the efficiency(or reliability) of the big block engine.

They could use smaller, high speed pumps and use a smaller, higher revving V6 but it isn't as efficient.

Exactly, it's about displacement to load ratio technology allows.

But I'd say that most of the amazing technology we see on production cars right now was availible back in the 60's.

The Ford Cammer was making about 93hp per liter, and nearly 80 torque per liter. Not bad for a 7 liter engine. It was also carborated of course, and running mechanically/vacuum controlled ignition.

But it was also designed for leaded gasoline. Running it on todays gasoline the same exact engine would have to have reduced compression, robbing it of power... But if you replaced the carb with a good EFI system that also controlled the ignition, then the compression ratio could be kept where it was from the factory, making the same, if not more power.

Not bad for 60's tech eh? If rebuilt with low friction coatings (availible then, just not on production cars) then efficiency goes up. Add EGR functionality, and cruise efficiency goes up.

I bet if you took an origonal SOHC cammer engine and massaged it a bit you could see modern fuel efficiency out it, when comparing it to like sized engines (7 liters/427cubic inches).

These engines also had variable valve timing... Not electronically controlled, but they had it. Honda is noted for the first use of it on a production car because it was electronically controlled. It was an inherent feature of the engine, not just an add on. Ford designed it for nascar guys, so that once the car's tires and everything else was up to race temps they could squeeze some extra power out of it.

but if you don't need the load. if an engine is efficient under heavy loads and you are running on flat ground and just driving yourself around then you can do with a smaller less efficient engine.

my car most of the time runs under 40% load. that being said, it would be stupid of me to put a V8 in it. my efficiency under load would go up but only when I had a heavy load.

the example of the water pump is truely apples to oranges. my load varies from the time I crank the car until I cut it off. an irrigation pump keeps the same load (relatively) and same RPM level (relatively) the entire time it is running.

if you could take a truely sub-standard engine (displacement wise) and put a turbo on it, you would get the mileage of the small engine with the help of the boost when needed. if you could gear it to where your running gear kept you at 1500-2000 RPMs at highway speeds, you would see the benefits of the small displacement most of the time. and you could get out of your own way when the time comes by spooling up the turbo.

I said this before in this thread. dodge/chrysler came out with a concept that used a 3cyl turbo engine. it was no where near fast. it didn't make it to production. it was called the slingshot. I think it was in 2004. that is the concept that I would like to see.

*edit* I don't know a lot about diesels but isn't that the concept behind the little turbo diesels that they used to have in the VWs a few years back and the reason they got mid 40s from the factory?

Good points all of them, but there's something else to keep in mind and the water pump analogy points it out well. It's not always just about max efficiency. Any engine has certain conditions where it really performs. For the big block V8 its low rpm heavy load conditions. For my little D15 honda engine, it's light load, moderate rpm (3000 or so) and for my 2.3L cosworth mercedes, it's heavy load, high rpm (6000 plus). None of these engines are guaranteed to be more fuel efficient than the others except within the conditions where they work the best.

Unless you drive under a very narrow set of circumstances (Over the road truckers do that, but few other drivers do) you're going to be moving in and out of the most efficient range of the engine in question. You can either try to adjust the car and the engine so that the max efficiency occurs in the range of the most common driving conditions, or you can try to widen the efficiency range of the engine to cover more driving conditions (but like a torque curve on a dyno graph, you'll end up with lower peak efficiency over a wider rpm range). You can do both of these things with a turbo depending on how you build the system and size the turbo.

The problem of a turbo either spinning up early and running out of gas, or not spooling until late in the RPM range is a dead issue. The turbochargers designed within the last decade are leaps and bounds ahead of what most people realize and are used to. The old standby garret t series turbos are such old technology at this point that I think they should be scrapped altogether by the garage tuner crowd. They have major performance limitations compared to the new generation turbos which can perform over a wide variety of driving conditions, rpms, and throttle loads.

In terms of the small engine vs. large engine in the same car. You're only presenting half of the argument. Put a 4 cylinder into a chevy pickup and it's not likely to get any better mileage than a V6. But the V6 chevy pickups definitely get better gas mileage than the V8s... (and in case you haven't driven a full size pickup with a chevy V6, I have. Believe me they have just as much get up and go as the V8 models.) Similarly, if you put a V8 in a honda, I'm willing to bet you won't get better gas mileage than the stock 4 cylinder. Ditto for a big 6 cylinder. All this is because to move a certain mass at a certain speed it's going to take (setting things like gear ratio and wind resistance aside) a specific amount of power. Change the mass you move, and you change the power needs and the best engine for the job. If you can accept that premise, then you can move on to how to extract the needed power in the most efficient manner.

Diesels inherrently get better gas mileage, and basically run on knock/detonation. This allows them to run much more agressive turbo setups that produce tons of intake temp heat with little to no negative effect.

Diesel and Gasoline turbo setups are apples to oranges.

And I agree that if you're only ever using 40% of your engine, then you could probably survive with a smaller displacement engine and get better efficiency out of it.

But realistically for production cars they can't go much smaller. They can, but not much. Safety standards make it extremely hard to make a light AND affordable car, and with curb weight averages where they're at it's hard to use a small engine that still makes people happy.

The big downside to using smaller engines though, is that the difference in MPG will be quite obvious as you add passangers, drive around the city, or drive over steep hills. You'll be working that engine pretty hard, or going painfully slow. I'd assume the people here might be ok with going slower to not push the smaller engine too hard and keep efficiency, but the average driver will just drive harder and get worse gas mileage than if they had a larger engine.

I think the factory Civic VX was a very good balance of economy and power. Even the CRX HF was pretty good. Plenty of torque for the weight, and due to it's small nature it would be hard to add too much weight to kill the mileage for that power range.

Now, if you put a 1 liter engine in that same car, the torque is going to be severely hindered. Adding a turbo would then be REQUIRED to have any efficiency under acceleration or load.

That's not a bad idea, I never said it was. I'm just still trying to figure out for myself weather or not adding a turbo to an already efficient setup will actually help.



Oh, there was some talk about the costs to try this out by HAL9000. I might beat him to it if things go smoothly the next 6 months. I'll have megasquirt installed for under $1000 in the next 4 months or so (maybe closer to $600, but I'm budgeting high). Once that's done I can tune it and see what mileage I get on the stock T04B 40 trim. Then I can upgrade to a T04E 46 trim which seems perfect for getting some mild boost on the freeway and still supporting enough airflow for my goals. Those turbos run about $100 used, and rebuild kits are cheap.

As far as I can tell HAL, we completely agree upon the engine size discussion.

The reason to have a V8 in a truck though, is that when towing the V6 will NOT be happy, and I HAVE done a fair amount of towing. It's amazing that a F-250 with a 460 Ford can get nearly identical mileage unloaded as it does under a 2000# tow. Most of the difference mileage is aerodynamic. A V6 with similar HP would be severely compromised by that load.

I had a 1 liter metro that got around 46 mpg about 10 years ago (I didn't care about mileage back then) it weighed about 1800 pounds. did it bogg when I had 4-5-6 people in it? yes!!! I actually had 7 in it at one time (back when my friends were all little). the fact is that you don't buy THAT car to haul people.

I have been playing around with the idea of getting a wildfire. it has a brisk 26HP motor. if they made it with a little more tail and could go 65 easily, I would be sold on the car. that is more my point. there is a market out there for these cars if they were to make one with say 40 or so HP and could go highway speeds. of course I wouldn't haul many people (if any) with me when I drove it. also it weighs about 700 lbs. (been a while since I checked, I may be wrong). it gets away with it because it is a 3 wheeler and is considered a motorcycle.

the 40 hp I am talking about could easily be achieved with a small turbo on maybe a slightly larger motor and the speed could be done with gearing.

I do also agree that there won't be much advantage (if any) to adding a turbo to an existing car. especially if you take into consideration the cost of the turbo setup.

Can't go tooooo much smaller though. My Rebel will only get 65mpg on the freeway. That's a 250cc engine around peak torque and 85-90% throttle. Peak torque is about 7000 and that's doing around 70. So that engine is running as efficiently as possible on the freeway and only manages that. The engine is maxxed out around 80 on a flat road.

In town it is more than enough and gets in the high 90s but it's completely gutless otherwise.

The way I drive my VX, it could easily survive on a 1 liter engine with supercharging, or turbocharging for the very small percentage of time when I actually need more than 30-40 horsepower. I seldom exceed 2500 RPM in a whole tank of fuel.

If Alfa Romeo could get 390 horspepower out of a 1500 CC enigne in 1950, how much more power do you want in a 2000 pound car. I think 300 HP out of 2.5 liters would be fine. Consider the Honda S2000 at 245 out of 2 liters without supercharging.

How many horsepower do you need to pull a trailer? Most of it is used to accelerate the total weight, then the power demand drops off quite a bit when all you have to do is maintain speed.

Hypermiling itself realizes the fact that almost without exception cars are overpowered. The less percentage of peak power output needed to maintain a highway speed, the less efficient the vehicle will be as far as mileage.

Get the CD down to .19, a totally practical figure, and the power necessary to maintain speed drops, but so does the percentage of power (compared to best efficiency) and mileage will not increase significantly without reducing engine displacement to increase percentage of load.

Stop thinking about the engine itself as the source of power. Capacitive storage of energy, with indinitely variable transmissions, will allow a vehicle to accelerate to 60 MPH in less than 5 seconds, regardless of the engine size. Small percentage peak power demands should be provided by stored energy, not some hugely oversized engine.

Think of it this way, you have a guage that instantly gives you the exact power your engine is producing, and gives you a graph of the time period of operation.

A turbo give you the ability to use a 2.5 liter 4 cylinder engine in a pickup truck, and haul a load. You just need the infinitely variable tranny, and the turbo to get you up the mountain, the only place where sustained demand approaches maximum power output for any significant period of time.

Sure you wont be able to climb a 10% grade at 80 MPH, but for twice the mileage I would be willing to make that sacrifice.

regards
gary

DKJones, wrap that Rebel in a real aero envelope and you would probably get twice that mileage.

regards
gary

Gollum
Our views are definitely only a few degrees apart, but that's the nice thing about polite conversations. You have the opportunity to really get into all the nitty gritty little details.

Personally, I think you could do the MS conversion (I'm assuming that it's on the 280) for more like $400. I picked up a broken MS box and repaired it for under $100 including the cost of a stimulator to test it. Fuel injectors, rails, and harnesses can be had on ebay for a song, as can throttle bodies, O2 sensors, and all the other parts you need. Enough people have done conversions on the old datsun straight sixes that you should be able to find the "grassroots recipe" on the msefi forum. I put all the parts together for my mercedes (except for the manifolds which I have to custom fabricate this winter) for under $1250. That's to convert the car to efi and build a custom turbo system AND modify the engine internals to put up with the roughly 125 hp/cylinder that it'll be producing.

Regarding how small the manufacturers can go and keep the public happy. Look at the cars in the UK and other European countries, India, Japan, China, and the like. That's the direction that we're going to end up going whether we like it or not. There's a reason why the average fuel economy in the US is in the low teens but in the high 40s in Europe. The fact is that Americans are behind the times in terms of average fuel efficiency because we've never paid the "real" price for transportation at the pump. Most European countries build their transportation/road taxes into the price of gas, so it becomes a real pay-per-use tax and people can see what it costs to drive a mile. If America did that I think the shock would make many of us change our habits substantially. (Or we'd lynch the local legislators!)