PacerX

Yup, want doesn't have anything to do with the issue, FMVSS does. Those are FEDERALLY MANDATED, no "want" involved - it's the law.

Law. Dead people. No bumpers. Not a want.


Size = mass. Furthermore, the teardrop shape then gets too tall if you want to have someone sit in the back, and then the frontal area is too large and all that work you did on Cd goes right down the toilet because the frontal area part of the equation goes out of whack. No worky.


Packaging dictates that you still need an engine compartment an a trunk... along with crumple zones, which means the teardrop still doesn't work. Look at an EV1 some time, that's as close as you're getting.


Only if you're not quick enough to catch on.

Corvette is one of the premier vehicles to pick if you're looking at the ultimate possible in Cd. It's the most likely machine around to sacrifice interior space, trunk volume, etc... in the name of Cd and reduced frontal area because it gets huge benefits from the exercise at top speed - and it STILL doesn't look like a teardrop.

Now, if Dave Hill will spend BIG $$$$ to save 13 pounds on a magnesium IP crossbeam, don't you think he'd shave down the Cd as much as humanly possible since it doesn't really cost any extra money? Corvettes look like Corvettes for a reason... and that reason is that they are pretty close to the ideal shape for a 2-seat vehicle with reference to Cd when other factors that are just as important are considered.

Ask yourself a question:

Why do Corvettes have that God-awful ugly coach joint at the rear?

Cd.

It most certainly isn't pretty, it isn't easy to produce repeatably, and people have complained about "big-butt" Corvettes for years. The reason it's there like that is Cd.

Again, Corvette is one of the most likely vehicles out there to sacrifice something in the interests of Cd, and it still doesn't look like a teardrop.


That's flat-out wrong. Efficiency = economy. The more efficient an engine is, the less fuel it uses at a given power level, the less space it consumes, the less weight it hauls around.

The LSx family is the poster child for efficiency in all of these respects. That's why Camaros get better fuel economy than Mustangs, btw... big old monster honking V8 just loping along at low rpm but making a stomping herd of torque.

Even the Nissan 350Z, with a much smaller engine and much lower power is less fuel efficient than the LSx Camaros were.

Why? Because that big old monster American V8 can turn a .5 6th gear and run all day at 70mph while spinning just off of idle. The itty-bitty weenie motor has to spin at a higher rpm to make power, and because the energy equation is .5*mass*velocity^2, the little motor screws the pooch. It is precisely the fact that the little motor has to spin so fast that causes the issue. Happily, a large motor also makes it very easy to make gobs of power, and will naturally tend to be more efficient UNDER LOAD.

Think of it this way...

It takes more gas sucked into a 2.0 liter motor to spin it at 4000rpm than it does to spin a heavier 4.0 liter motor at 2000rpm - why? Because it takes VASTLY more energy to spin a relatively light reciprocating mass at 4000rpm than it does to spin a HIGHER MASS at 2000rpm. Remember, velocity is squared in the energy equation...

There goes your power vs. economy theory again. I can blow holes in that one all day long, keep 'em coming...



400hp/28mpg = 14.28hp per mpg
103hp/35mpg = 3hp per mpg

So, if your theory is correct, we could drop a Corvette down to 103hp and it would get 49 mpg.

Not a chance.

You're wrong. Next.

Chris 96 WS6

Hey no problem.

I guess you could mount the rear wheels on pedestals but then you have the issue of a perfectly symmetrical teardrop being awfully tall and tip-over prone. You end up having massive frontal area, which defeats the purpose of the teardrop shape.

With regard to the Camm type rear. I'm sure its not as clean aero-wise as a teardrop rear, but like Pacer X alluded to it comes down to functional issues like a useable trunk. Within the design envelope available for modern, saleable cares, I think we're getting the best overall shapes we can get.

You could reduce CD and frontal area by outlawing all side-view mirrors, but that would be pretty dumb. Its a functional requirement that you can't overcome without giving up safety, much like bumper and headlight height requirements.

Lightweight materials are great for reducing mass for acceleration, which improves in-town MPG, but mass doesn't affect steady cruise consumption much.

I think if we could increase tractor-trailer and over-the-road-bs highway MPG by 1-2 we'd probably solve the whole issue for the near future. Problem is that's a 33% increase, hard to acheive. I'd like to see some work done to make the tractors more aerodynamic beyond what's been done in the last 20 yrs.

Ken S

noone in America really wants to sacrifice $, performance, size, and confort for better gas milage.

As much as love our gas powered vehicles, I'm starting to think we're just better off jumping totally over to another energy source/transport. IMO, its not really the enviornment that concerns me, at least in the relative short term, its the dependence of foreign oil as one of our main sources of energy.

Energy is as important to us as food.. Without energy, we can't distro food effectively and supply the machines with parts and energy to help gather and process food. Alot of our military equipment would be useless either.

IMO, the best thing for this country is to figure out a renewable energy source, storage, transport, and use tech that we ourselves can maintain. When energy becomes almost free, it can open up the doors for alot of things..

for example, manufacturing new materials that are currently too expensive because the amount of energy it takes.. if energy becomes dirt cheap, suddenly that part of the problem is effectively solved..

or even computing power.. The lastest supercomputers in the world, take MILLIONS of dollars a year to just keep it powered and cooled (lots of heat)!

I think it would be better if we are able to become more independent on our energy needs, and also figure out how to make more of it cheaper, through our strong points in innovation, R&D, and manufacturing.

Then instead of fighting wars over energy resources, we could end them, by supplying energy to other contries, effectively controlling them.

Chris 96 WS6

I don't have any real problem with anything of substance in your post, but it didn't fail to catch my attention you started out your final point with this rather cocky statement.

So you're convinced your ideas are consitent with the definition of a "true American" ????

Like I said, I generally agree with everything you said but the attitude of that final statement is pretty annoying to say the least. Who are you to define what a "true American" is, and who are you to decide that you fit that definition? By default you are implying that anyone not agreeing with you is not a true American.

Ken S

Sorry about that, I was being a little sarcastic.. I'll edit it out..


IMO, I think the majority of American's don't really care how much energy/resources we use, as long as its cheap and doesn't directly hurt us. This is why we all like big and fast cars, and want to live in big houses and such. Craft food to be more nutritionally empty, rather than eat less of it.. etc..

Also, I think it is the best if we controlled our own major source of energy.. I honestly believe that is why our government always has their thumb stuck in the oil pie, and in the end, all of our global actions is to insure our energy supply doesn't become unstable.

I also darkly envision if the US does effectively figure out a better energy source, trransport, storage, use etc, that it'll use it to advantage to leverage the control over the world.. Thru dominance of military tech and polical crafting.. (Energy for food).. Imagine if it was ecofriendly.. The US could use that angle to push other contries to use our energy, "to save the world from the biggest threat of all to mankind, environmental damage!"..


In other words, we can drastically improve the living conditions around the world, clean up the environment, supply ourselves with cheap energy, and probably the most important thing to our gov and military - make the world dependent on US! At least until someone figures out how to make it themselves.. but then, we can always try to control that by saying that this tech must be ultramonitored because it is too closely related to the next most powerful WMD, right?


Thats my plan to take over the world at least.. Feel free to use it, as long as you give the US government exclusive rights to it..

and lets hope the citizens don't get the shaft... which we unfortunantly probably will anyways.


BTW, I'm saying all this with a half sarcastic smile.. But in a cold, dark way, I think it sounds like a good plan, especially cause you can justify it in such a positive way.. "Safer, cleaner, higher standard of living for all POWERED BY THE USA! lol!"

Chris 96 WS6

The fastest and currently most cost effective thing I think we could do short term is go Nuke & hydroelectric for all our electric supply. We are like 20% nuclear. Japan and France are over 80% nuclear.

With a near-limitless supply, this takes polluting coal out of the picture, which is a finite resource anyway despite us having plenty of it still, and it would also eliminate natural gas plants that are going to get expensive as supplies start to dry up.

We could all switch to electric appliances and get off natural gas completely, and homes in the NE could get off of home heating oil, which would massively reduce US demand for crude oil.

That doesn't fix gas prices instantly, but I think it would help. Refinery capacity is woefully low right now too, so gas is going to stay kinda high even if oil comes down a bunch.

But, that would be a start in the right direction. The article does have a good point that electric cars can be charged in off peak hours, and if hybrid/electric cars proliferate it would be a readily available technology to stem oil demand. BUT, and that's a big but, the cars have to come down in price to be competitive in the market.

Z28x

What is the gov't going to tax if we all start using electric cars? The blood suckers will find away to screw the public no matter what.

Ken S

they'll figure out a way to watch us with the dreaded future OBD enhancements.

muckz

Hence somebody does not want tear-shaped cars. His statement, and my statement for that matter, are both correct. Neither of us specified who or why they're not wanted. I don't know what you read into.

What you are talking about is practicality. You are dodging the original point raised, and that was that the teardrop shape would be more aerodynamic than current vehicle shapes.


Again, practicality was not the point. The argument centered on Cd. You put a lot of work into your replies, thinking elaborate examples, bringing things up that are not related to the original discussion. You are wasting a lot of energy, you are not running very efficiently.


Still waiting for you.

Correction: the ultimate possible in Cd with <b>current car shapes</b>.

You know, I'm starting to laugh as I write this.


I swear, I nearly forgot what it was that the original post was about. You're not trying to sell me a Corvette, are you? Because I believe we were talking about Cd of present cars vs. a theoretical tear-shaped car, with which Corvette has nothing in common.

Corvette is the LAST vehicle to sacrifice appearance <i>drastically</i> for Cd, and by drasticly I mean as appearance approaches the tear-drop shape.






There, again. You do it again! Efficiency - yes. That's not what I disagreed with you upon. Fuel consumption? Read my comments down below...

Your comparison is wrong and invalid, and I am going to tell you why. If you wish to establish the effects in variation of one variable (displacement), you isolate that variable and hold all other variables constant. This means engine remains the same, the only difference being in displacement. The fact that Ford engine eats more fuel while having lower displacement is worth jack if you're comparing it to the LSx series of engines because they are too different.

What you want to do is take two identical engines, then bore one out. And if you still think that the bigger engine will consume less fuel... then I hope you get a refund at whatever school you were going to.

I think you are too hasty. Let's not be too hasty. You are jumping too quickly to something else without first thinking about what I wrote or what it was that I disagreed with you about.


The only holes you're blowing is in your own logic and comprehension of the discussion at hand.


What you are referring to is efficiency.

Nope, not at all. That's not my theory. That's your own theory.

Actually, this is what newbieWar said:
<i>if the vett, with 400 hp can get 30mpg, then GM should be able get lower hp engines to get better gas mileage</i>

Well, why don't we see if the 500 HP Z06 engine will be more economical (note: economical, not efficient) than the 400 HP C6 engine.

Generally speaking, performance is squeezed out at a cost. You cannot be producing more power and at the same time consuming less fuel, assuming both engines are optimized at their respective power levels (again, same engine, not Ford's OHC vs. GM OHV).

DO
LOOP

PacerX

I read this:

"...because people don't want them to be"

How about it's because the packaging of a teardrop shape for a vehicle DOESN'T MAKE ANY DAMNED SENSE AND IS A PRETTY STUPID IDEA IN THE FIRST PLACE, not because "people" don't "WANT" to do it.



What the heck is the point of designing a completely impractical car? ESPECIALLY since a .28 Cd is about the best ANYONE ON THE PLANET can do at this point in time and still manage to fit human beings inside it (note the plural) AND meet all the Federal Requirements???

The GM Solar Racer thingy was a dead-on teardrop. ONE person sat PRONE in it to drive it and if it ran into an possum, odds are the driver would have been killed.

Junior's point was that stupid people are simply too lazy/stupid to get around to designing a vehicle using his pet shape that someone told him was better for Cd... which it is, until you actually want to make it into a vehicle to... you know... actually CARRY PEOPLE AROUND IN.

Come up with a guided, unpiloted car that carriers no passengers or cargo. Let's see how many of them sell.



You're right. I'm casting pearls before swine.


It absolutely HAS sacrificed appearance for Cd. The pop-ups bit the dust in large part because of that. The C4 AND C5 were smooth, wedge shaped and very long in comparison to other sports cars specifically because of aerodynamics. It's got the big old butt on it for aerodynamic reasons.

Because GM looked at the teardrop shape and said... "Boy that'd be stupid, there's no place to put the people..." doesn't mean that no one looked into the shape in the first place. Furthermore, GM pays A LOT of very smart people A LOT OF MONEY to come up with the ideal shape fror a vehicle.

And it ain't a teardrop.




This oughta be good...

DISPLACEMENT was not the variable held, POWER was. Did you bother to read that part. The wonderful thing about POWER is that DISPLACEMENT just happens to be the easiest way to make it.

Wrong already, and we're only on the second sentence...


Wrong again. Power was the isolated variable, NOT displacement. Power was then compared in relation to miles per gallon. Here's the equation again:

400hp/28mpg = 14.28hp per mpg
103hp/35mpg = 3hp per mpg

One makes more power than the other (the LSx wins there...) AND has better fuel economy. Therefore, POWER and ECONOMY ARE NOT INVERSELY PROPORTIONAL. Less power DOES NOT EQUAL higher fuel economy.

Here's another example:

The S2000 vs. the Camaro...

The S2000 makes JUST OVER 100hp less than the Camaro, is lighter, and has a lower frontal area, but STILL doesn't get better fuel economy. Why? That's a state of the art engine, right? Variable valve timing! Two less seats! 4V per cylinder! Roughly 1/3 the displacement! 1,000,000 rpm redline! Much smaller car! Lower moments of inertia in both the engine and at the wheels!

NO SIGNIFICANT FUEL ECONOMY DIFFERENCE.


Once bore is changed, a whole raft of other things will have to change also (cam timing, fuel mapping, cylinder heads, valve sizes, etc...) but the larger motor, when all is said and done, will be able to drive a taller rear end gear and therefore require a lower engine speed for a given vehicle speed and therefore yield better economy. Concurrently, the larger motor will make more peak power.

A large number of the things that make greater power - more efficient heads, higher compression, sophisticated fuel management, lightweight pistons, lightweight rods, low valvetrain mass, ALSO make MORE POWER.

GM and Chrysler went to large displacement 2v V8's for that very reason. Displacement is a less expensive and more efficient way to hit a given power target than the added complexity and of a smaller displacement, lower power, but more complicated engine.

Ford, on the other hand, blew that one straight out their collective asses.


You absolutely can. GM has proven it. Honda put their best effort into the S2000 motor and got spanked by an "old tech" big displacement, high-power American V8 in the fuel economy contest. Ford lost on both counts also. The Hemi, the LSx's veritable twin, is the only engine even close.

Anywhere from 240hp to +400hp, NO ONE and I mean NO ONE can deliver the efficiency and economy an LSx motor can. Everyone else has tried, and failed. Throw DOD on, and the case skews even further towards the high-powered LSx motors.

Ken S

For EPA ratings.

However, in the last R&T comaro, the "our driving" mpg rating for the Vette was one of the worse only one it beat was the Viper

12.9 mpg Vette
23.3 mpg S2000

With the big displacement, its alot easier to waste more gas in real life. we all know that from experience.

NewbieWar

... now that i have been thoroughtly bashed and i appreciate any help given my way... i was just saying that the body styling could be pushed forward,

some big rigs use a block design w/ a bit of modification could be turned into a tear drop and they are allowed to drive like that...

but a cvt behind the corvette engine and ud probably get it into the mid 30's and maybe higher... like gm said theres can give a 11% increase in efficency, although the tranny now cant handle that kind of torque...

although big rigs and trains use desiel so its hard to compare the two...

because the bug can get 50 mpg out of their desiel or they used to (99 model was the one i drove to denver in)

someone in here said that having a flat bottem was bad, if that were true then why would the exotic cars mostly have sealed undersides? I'm almost certain the Diablo has the bottom completely sealed off, its because on my firebird everything the wind hits is like a sail, like the rear bumper its just like a big parashoot (spelling lol)

but yes the hybrids aren't worth the money... the carolla vrs the prius (not exactly the same catagory but ok) you would have to drive 100,000+ (at 2.50 a gallon) miles before you broke even w/ gas to afford the hybrid, but then to make it less worth while you must replace the battery on the hybrid every 3-5 years... and those are expensive...

so hybrids are they worth the money? not really... if the technology got more common and cheaper perhaps... toyota (i think GM does too) has a concept out that creates 400+ hp out of 2 electric motors and a gas engine and still gets mid 20's for gas mileage, but there are still corners to be cut on the hybrid technology i think they ought to get away from batterys and on to compressed air for stored power, you can charge it as quick as you can get resistance, and i dont think it weighs as much...

but please be easy w/ peoples comments I'm not a engeneer at least yet, and im only 19 a very impretionable teenager, who has had about 2 year of medioker intrest in cars (since i got my f-body) and now i'm trying to get educated and put in my 2 cents... please dont jump down my throat for something

Meccadeth

Hybrids aren't solely about being worth the money. First off, if you do a lot of city driving, then a hybrid will pay for itself with gas savings MUCH sooner than 100K miles compared to a similar vehicle. Its closer to more like half or a 3rd of that amount of miles.

Secondly, having a car with 350 HP isn't worth the money either. Where does a more powerful car pay off in terms of fuel economy or any other aspect that puts $$ back in your pocket? It doesn't. You get powerful cars for the pleasure it brings you, which is the same thing that many hybrid owners buy their cars for. I had MUCH more fun trying to squeeze out the most MPG I could out of my Honda Insight than I do taking my Z28 to the track and playing with Civics on the street. Buying a hybrid isn't just about saving money on gas, its the pleasures it brings you under your ownership.

NewbieWar

so you enjoy your hybrid? thats good, but the cost of a $20,000 car vrs that of maybe a $15,000 car w/o a hybrid generator... assumably the same car the gas mileage is not a good reason to buy it, just like buying a desiel fuel ecconomy usually isnt worth the extra Dollar that the desiel upgrade is...

simply doing the math, compact cars w/ small engines are the most efficent and best bang for the buck...

enjoyment is another issue tho

90rocz

I don't agree, it would be Political suicide, and I doubt the economy could take the shock.(no flame, being realistic)
On the flip side, I don't see why, in the 21st century, we have SUV's getting a paltry 14/16mpg...in anything??
I have gotten that kind of milage out of my 5,600LB 1988 4WD Chevy TBI/EFi rolling BRICK, Suburban. And 12mpg in 4WD just this winter; why has the milage efficiency stalled with over 17 YEARS of technological improvements???

I DON'T expect 50mpg from anything, but 35mpg+ isn't out of range of the average car today...IMHO. (25mpg truck)

I totally agree with this, b/c I have experienced it. People around here used to brag about smaller motored trucks getting better milage.(hence 5.0L sales) But didn't take into account torque and hp and throttle required to move. My uncle had an '85 Chevy 1/2 ton with a smaller 305 engine, and didn't believe I got better mpg in my 350 ci Suburban. I drove his truck a few times, it took "more PEDAL" to accelerate than my Suburban and used more fuel. I know gearing probably played a big roll too, but a larger displacement(..lever..)requires less power to move something.