Who would win: 03 Cobra or 05 Vette?

Some idiot (wont mention who.. he used to be a member here but was banned after like 3 days because he is an idiot) im's me every chance he gets. Not that I mind that.. but THIS i DO mind!
He is trying to tell me that an 03 Cobra will get better mileage, make more power/torque, weighs less, tops out about 200 or even better, etc. His proof? "I work at a focking ford dealership doosh", than an 05 Vette. He is also trying to say that there is a "wastegate" on that -supercharged- 03 cobra that lets him get good mileage, and better torque down-low compated to an 05 Vette.
So.. which is CLEARLY better?
Matt

The cobra outweighs the c6 by leaps n bounds...stock they run very similar times...and rated at almost the same power...he's obviously clueless...when you mod both anything can happen, but the cobra wakes up big time from simple mods.

Ya, i knew the cobra WAAY outweighs a C6.. but stock for stock, the same exact driver for both cars; Vette or Cobra?

Ya, i knew the cobra WAAY outweighs a C6.. but stock for stock, the same exact driver for both cars; Vette or Cobra?
its hard to tell, it would be a pretty even race, but corvette will prolly win , since im a gm fan, any ford fan will say teh cobra so u know

Pretty damn close in a straight line.
But the C6 is about 400lbs. lighter, has two seats, a lower center of gravity, more advanced chassis and suspension and is designed to do one thing...perform.
It's like comparing apples and oranges.
S.

Per magazine times, the C6 will win, but in reality they're so close that it's a drivers race. Add a CAI and cat-back to a Terminator and you'll pick up 30 to 40 horses. What I've read in MM&FF is that because of the blower noise, Ford was basically forced to really choke down the intake and exhaust of the Cobra to meet Federal drive-by noise standards. Because of that, those simple intake/exhaust mods that might only net 10 to 20 horses on other cars are doubled on the Cobra.

Pretty damn close in a straight line.
But the C6 is about 400lbs. lighter, has two seats, a lower center of gravity, more advanced chassis and suspension and is designed to do one thing...perform.
It's like comparing apples and oranges.
S.

A man with a '97 cobra who bled blue to the bone once told me his thought of a comparison on the new vette and cobra. The Vette's IRS was designed INTO the platform. The Cobra's IRS was a last drawn-up thought brought about by Ford/SVT that they just kind of "threw in" there. He told me he got to drive both at MIR at some track meet, and the difference was night and day. Never have gotten to drive either, but my nod goes to the vette anyways :D

~Jon :metal:

The Vette weighs less and has close to the same HP. Drivers being equal the Vette would win. Assuming the Cobra is stock. Take it to the twisties..The Vette would OWN.
Cobras are mean though.

Wow.. I never thought so many people would say that in a straight-line the race would be very close. But someone please back me up when that idiot says the Cobra will top out at 200mph..

But someone please back me up when that idiot says the Cobra will top out at 200mph..

I will back you to hell and back about that! A stock Cobra will top out about 155 mph because of the speed limiter. A stock Cobra w/o a speed limiter was projected by Ford to do about 180 mph. A stock Viper only does about 190 mph. No way in hell a stock Cobra will hit 200 mph w/o a long downhill strech with a hurricane tailwind. :D Send that moron to this site and we will set his ricer a** straight!

^Lol.. funny part is, he WAS a member of this site for 3 days until being banned by the mods for posting chopped, fake-ass pics of some Camaro's and everyone took him serious. But seriously; the new Vette w/ 500hp is going to top out near 200mph, no way in HELL will a 38?hp Cobra top out anywhere NEAR that.

^a 38?hp Cobra top out anywhere NEAR that.
390 lol :rolleyes:

to start off this may be the first and only time you see this.....i'm a ford guy but......i got to give the new 2005 C6 Corvette the props........the new 2005 Corvette C6 i think will kill the 2003 Cobra.yea the cobra may have a lil bit better off the line power but it only top at about 150 - and pushin it and if your a damn good driver it might do 165 M.P.H.Tops....But the 2005 C6 Corvette i know for a fact will do 200+ M.P.H.TRUST ME....
i know...lol.i have drivin one.. :D

But seriously; the new Vette w/ 500hp is going to top out near 200mph, no way in HELL will a 38?hp Cobra top out anywhere NEAR that.

Very true. The Vette has a lot more hp and is way sleeker. Have the moron register under a new user name and we will bash him till he runs away.

to start off this may be the first and only time you see this.....i'm a ford guy but......i got to give the new 2005 C6 Corvette the props........the new 2005 Corvette C6 i think will kill the 2003 Cobra.yea the cobra may have a lil bit better off the line power but it only top at about 150 - and pushin it and if your a damn good driver it might do 165 M.P.H.Tops....But the 2005 C6 Corvette i know for a fact will do 200+ M.P.H.TRUST ME....
i know...lol.i have drivin one.. :D

No. Ford said a Cobra w/o a speed limiter will do about 180. A new Vette does 186 according to the car rags.

well the mag must have not had been pushin it hard..we got my buddys bone stock Corvette doin about 200

well the mag must have not had been pushin it hard..we got my buddys bone stock Corvette doin about 200

No you didn't. Unless if you mean 185ish as 'about 200'. The C6 can attain 186 stock, and a little more with the mirrors folded and some high speed tape (still less than 200), but trust me, you didn't hit 200 in a stock C6.

It doesn't sound like much, but 14mph on the top end is a huge difference, as aerodynamic drag is a function of frontal area, vehicle Cd, and velocity CUBED. They aren't even stating that the new Z06 will do 200mph, and it has another 100hp.

Sorry, try again.

well the mag must have not had been pushin it hard..we got my buddys bone stock Corvette doin about 200

PLEASE EXPLAIN TO ME WHERE YOU AND YOUR BUDDY WENT TO TO TEST THIS, AND GO THESE SPEEDS?!?!?!?!?!!?!?!?!?!!??!!?!?
:rolleyes: :rolleyes: :rolleyes:

No you didn't. Unless if you mean 185ish as 'about 200'. The C6 can attain 186 stock, and a little more with the mirrors folded and some high speed tape (still less than 200), but trust me, you didn't hit 200 in a stock C6.

It doesn't sound like much, but 14mph on the top end is a huge difference, as aerodynamic drag is a function of frontal area, vehicle Cd, and velocity CUBED. They aren't even stating that the new Z06 will do 200mph, and it has another 100hp.

Sorry, try again.


:bow: :bow: Way to explain.
I have had very similar conversations with the local hillbillies who claim theyhave done 170+ in their 305 SS monte's :lol: They dont understand how fast that really is.

Personally, I have a hard time believing a bone stock 03/04 w/o the speed limiter would hit 180. Or even 170 (admittedly, I've never looked into it). Mustangs are not know for their aerodynamics.

But how does a Cobra have more off the line power??
Lol.. 390, my bad :o
That is very true though, stangs do NOT have very good aerodynamics.

But how does a Cobra have more off the line power??
Lol.. 390, my bad :o
That is very true though, stangs do NOT have very good aerodynamics.
It dont have more power off the line. It has a few less HP and alot more weight.

It does make enough power to stay near the bumper though.

well the mag must have not had been pushin it hard..we got my buddys bone stock Corvette doin about 200

Yeah, downhill in a hurricane.

^lol.
Now.. lets talk Cobra R's.

well the mag must have not had been pushin it hard..we got my buddys bone stock Corvette doin about 200You weren't anywhere near 200 in a stock Corvette.

^lol.
Now.. lets talk Cobra R's.

The stock '00 Cobra R should top out about 175+ w/o a speed limiter.

The stock '00 Cobra R should top out about 175+ w/o a speed limiter.This mag had it hit 170:
http://mustang50magazine.com/roadtests/13379/

LOL quality of driving has something to do with top speed? Maybe to avoid smashing into a wall, but other than that, find a straight road and keep the throttle wide open until your car stops accelerating.

LOL quality of driving has something to do with top speed? Maybe to avoid smashing into a wall, but other than that, find a straight road and keep the throttle wide open until your car stops accelerating.

Heheh, I was wondering about that. A better driver can what, drive straighter?

This mag had it hit 170:
http://mustang50magazine.com/roadtests/13379/

Man are those R's freakin sweet!!! Sheit.. they even have a friggen DIFFERENTIAL COOLER!!!11!! That rox, lol. But that is one Mustang I would NOT mind having ONE bit! How much hp they come with? Like 380?

A previous entry said that a Corvette was going 200+ MPH.
I, along with many others, add..."Hogwash" to the assertion.


Here is a link to what it takes to push 200 MPH:
http://racingarticles.com/article_racing-21.html

The amount of horsepower to overcome the aerodynamic drag at that speed is enormous, even with a slippery body shape.

A Vette with ~400 HP is not going to come anywhere near 200 MPH. It would take about 750 HP, along with oodles of other adjustments to attain that speed. Maybe you meant 200 "Kilometers"/hour. (which equals 124 MPH)

Sorry, I don't buy it.

This mag had it hit 170:
http://mustang50magazine.com/roadtests/13379/

Bad gearing and/or crappy aero = crappy top end compared to the Vettes. :( I think an LT1 Vette would do nearly 170 stock with 100+ rwhp less!

A Vette with ~400 HP is not going to come anywhere near 200 MPH. It would take about 750 HP,

Motor Trend got a stock '98 Viper GTS to 192 mph. It is rated at 450 hp. It would probably only take another 25-75 horses to hit 200.

You proved yourself wrong. Your link showed it only needing 475 hp to reach 200 mph.

Lingenfelter's cars often top out at 220+ with much less than 750hp.

But a stock c6 hitting 200mph? nope. 180? with good conditions.

The zr1's were able to top out at 180+ and they weren't quite as aerodynamic as the c5 & c6 cars, so I believe 180ish, but 200 bone stock isn't gonna happen.

Motor Trend got a stock '98 Viper GTS to 192 mph. It is rated at 450 hp. It would probably only take another 25-75 horses to hit 200.

You proved yourself wrong. Your link showed it only needing 475 hp to reach 200 mph.
this is probably comparing apples to oranges , but isnt teh mclaren f1 rated at 650 hp and its top speed is about 235 making it one of the fastest prodcution car in the world

^Yup, you are right :cool:

this is probably comparing apples to oranges , but isnt teh mclaren f1 rated at 650 hp and its top speed is about 235 making it one of the fastest prodcution car in the world

True, but the F1 weighs 1138 kg or about 2509 lbs. Comparing a 650 hp V12 at that weight to a 405 hp LT5 Corvette at closer to 3400 lbs is apples and carrots. Also, the F1 has much better aerodynamics, and it tops out at 240.1 mph making it THE fastest production car in the world. It also holds the fastest 0-100-0 record, 11.5 seconds and a total distance of 828.4 feet.

Also, the ZR1 has more usable RPM than the LS1/LS2/LS6/LS7. 7200 RPM is the redline versus the common 6100 RPM redline for GM's other V8s.

True, but the F1 weighs 1138 kg or about 2509 lbs. Comparing a 650 hp V12 at that weight to a 405 hp LT5 Corvette at closer to 3400 lbs is apples and carrots. Also, the F1 has much better aerodynamics, and it tops out at 240.1 mph making it THE fastest production car in the world. It also holds the fastest 0-100-0 record, 11.5 seconds and a total distance of 828.4 feet.

Also, the ZR1 has more usable RPM than the LS1/LS2/LS6/LS7. 7200 RPM is the redline versus the common 6100 RPM redline for GM's other V8s.Weight is irrelevant for top speed. You are fighting aerodynamics at that point, not weight.

Also, usable RPM means nothing as long as the car is geared to be at peak power at top speed.

A Vette with ~400 HP is not going to come anywhere near 200 MPH. It would take about 750 HP, along with oodles of other adjustments to attain that speed.

I don't know how you concluded that it takes ~750Hp, with or without the article link you supplied. No, it takes in the low to mid 400 horses to the ground, assuming a reasonably slippery car, to hit 200 mph. You can even have a poorer Cd IF you have a smaller frontal area. You cannot say that weight doesn't matter, but weight is only a very minor factor. Aerodynamic friction is enormous at those speeds, and friction due to weight is nearly insignificant in comparison.

Weight is irrelevant for top speed. You are fighting aerodynamics at that point, not weight.

Also, usable RPM means nothing as long as the car is geared to be at peak power at top speed.

Weight is never irrelevent. If it was, then you would see full weight stock cars running around the Nascar circuit. I see what you're trying to say, between intertia and the increasing drag at high speeds, but to say weight doesn't play a part is not true.

Also, if the car has more usable RPM, then it can have more gear which makes acceleration easier. :)

So, everything else being equal....ie power and aerodynamics....a 30,000 lb Vette would have the same top speed as a 3000 lb Vette.

Very interesting indeed.

And rpm range certainly does matter. I have practical experience with that one. :)

If you could fit that entire 30,000 lb Vette into the same shape as the 3,000 lb Vette AND if it didn't cause an enormous increase in bearing/wheel friction (but we know it would) then yes, their top speeds would remain the same. The acceleration rates and thus the time required to reach maximum speed would be VERY different, but top speed would be the same for both.

The power required to reach a particular mph is given by:

P=1/2 * Cd * A * rho * mph^3

Cd= coefficient of drag
A = frontal area
rho= air density

Weight is never irrelevent. If it was, then you would see full weight stock cars running around the Nascar circuit.Weight pretty much *is* irrelevant when you're talking top speed. The reason Nascar doesn't have full weight cars isn't due to top speed, it's because of acceleration.

Lets say we have a 3000 lb car with a Cd of .30 and frontal area of 20 sq ft.
We also have a 6000 lb car with the same Cd and frontal area. Both cars put down the same horsepower to the road and are geared the same. Both cars will reach the SAME top speed, but the first car will GET THERE much sooner. Within practical limits, weight is indeed irrelevant to top speed.

this is probably comparing apples to oranges , but isnt teh mclaren f1 rated at 650 hp and its top speed is about 235 making it one of the fastest prodcution car in the world

Every test I've read of the McLaren F1, they were not able to get it anywhere near the rated top speed. Anyone here seen different?

Wow.. you people are fricken SMART!!!!!!!!!! Jeez.. where did you all learn taht stuff, college?

The weight of a nextel cup car is around 3600 lbs..........I'd say pretty close to full weight.........

Considering the cars that they are supposed to be emulating, I guess you could say they're close to full weight, but typically a few hundred pounds lighter than the street version.

So, everything else being equal....ie power and aerodynamics....a 30,000 lb Vette would have the same top speed as a 3000 lb Vette. :)
Come on Bob, don't be ridiculous. You know damn well what I meant. Chris was comparing two cars that were only 900lbs apart. Not enough to effect top speed. Like I said, you are fighting wind resistance more than weight when you get up around the 200mph mark.

And rpm range certainly does matter. I have practical experience with that one. :) Your "practical" experience is with drag racing, unless you've been to Utah lately. We're talking top speed, not acceleration.

Come on Bob, don't be ridiculous. You know damn well what I meant. Chris was comparing two cars that were only 900lbs apart. Not enough to effect top speed. Like I said, you are fighting wind resistance more than speed when you get up around the 200mph mark.

Your "practical" experience is with drag racing, unless you've been to Utah lately. We're talking top speed, not acceleration.
Yes it is enough to make a diff. I hope people anint buying this . Ergonomics have alot to do with top speed but it is a combination of things including weight. The more weight you have the more force is acting upone you/your engine and the more power you need to move it. While Im sure there is a certain threshold of a few hundred pounds weight does have something to do with top speed. 900 is plenty to lower top speed. Weight dont dissapear as you go faster.
Years ago I read a good article about it somewhere a few years back. If I can remeber where I read it ill post it.

Gravity is directly affected bye weight. Remeber that.

900 is plenty to lower top speed.Not enough to be the difference in top speed between a ZR-1 and a McLaren.

Check this: a 3,600lb, 450rwhp Supra will not only have a higher top speed than a 370lb, 100rwhp R6, but it will absolutely obliterate the bike after about 130. And it's not because the Supra has a weight advantage, or even a power/weight advantage.

I'll give you one clue, and it starts with the letter "a."

Come on Bob, don't be ridiculous. You know damn well what I meant. Chris was comparing two cars that were only 900lbs apart. Not enough to effect top speed. Like I said, you are fighting wind resistance more than speed when you get up around the 200mph mark.

Your "practical" experience is with drag racing, unless you've been to Utah lately. We're talking top speed, not acceleration.
Ok. You're right. I'm ridiculas. 900 lbs is irrelevant. And I disagree.

I do agree that wind resistance (a function of aerodynamics) is a huge factor at those speeds. But weight matters.

You have wonderful day. :)

Ok. You're right. I'm ridiculas. 900 lbs is irrelevant. And I disagree.

I do agree that wind resistance (a function of aerodynamics) is a huge factor at those speeds. But weight matters.

You have wonderful day. :)Do you believe that 900lbs to be the difference in top speed between the two?

It would be part of the difference. How much I could not say, and I would suggest that you could not either. You can only assume, presume, and guess.

I won't pretend to be smart enough to do better.

How about my bike and Supra comparison? (Since you've got the practical experience and all)

Yes it is enough to make a diff. I hope people anint buying this . Ergonomics have alot to do with top speed but it is a combination of things including weight. The more weight you have the more force is acting upone you/your engine and the more power you need to move it.You're quite incorrect. First of all, "ergonomics" has absolutely NOTHING to do with top speed. You apparently have no idea what ergonomics even means. Look it up. Lastly, weight has little to no effect on top speed. Weight affects accleration rate, but not top speed.

The friction from the air is so enormous compared to other forces (remember, it's a cube function) that the minor increase in wheel and bearing friction due to weight increase is negligible. If you think otherwise, you simply have no clue about the physics involved.

How about my bike and Supra comparison? (Since you've got the practical experience and all)
It is likely that my practical experience (which related to gearing and rpm) is not enough for me to make an informed decision.

And to be honest, I didn't even bother looking much at your example. No offense. Even so, though my example was extreme (3k vs 30k), if there is a difference, then that difference would apply to a much smaller extreme (ie..900 lbs), though how much would quite possibly be very minor, as posted above.

You're right, it'd be minor. Dare I say irrelevant? I think I already did. And we're back to square one. Thanks.

Big Red Jim gets it, but some of you have this weight issue on the brain. Check out the following:

"There is a limit to what brute power can accomplish. Even Terry Kizer's 459- horsepower ZX-11 turbo has "only" gone 230 mph, greatly due to the horrific aerodynamic drag created by its slick-looking (as motorcycles go), but not aerodynamically slick, shape. " and "A common misconception about attempting to go fast is that it's important to get the bike light, as vehicles must be in most other forms of racing. If you have enough track to truly reach top speed, however, lightness becomes irrelevant. Light weight only helps acceleration."
http://sportrider.com/tech/146_9510_bench

The following primarily discusses the aerodynamic forces, which are a square function, but briefly discusses the power required to overcome those forces, which are a cube function. Note that weight is not a part of any of the equations. For all practical purposes, it's simply not a factor.
http://snipurl.com/cx1x

Here's a page that discusses rolling resistance, which is obviously dependent upon weight. Rolling resistance of a 2500 lb car is calculated at 33 lbs. Double that to 5000 lbs and it's still only 66lbs.

What's the aerodynamic force, ignoring rolling resistance, required to move a Vette through the air at 200 mph? About 450 lbs, while the rolling resistance for a car with DOUBLE the weight is only about a 40 lb difference in force required. Insignificant.
http://snipurl.com/cx23

If you have enough track to truly reach top speed, however, lightness becomes irrelevant. Light weight only helps acceleration."There's that damn "i" word again. :lol:

You're right, it'd be minor. Dare I say irrelevant? I think I already did. And we're back to square one. Thanks.
You're welcome - though whether or not it is "irrelevant" is rather debatable. Please see previous comment dealing with assumptions, presumptions, and guessing.

You're welcome - though whether or not it is "irrelevant" is rather debatable. Please see previous comment dealing with assumptions, presumptions, and guessing.
Nuke did my dirty work. No guesswork involved here. Consider yourself educated now.
The following primarily discusses the aerodynamic forces, which are a square function, but briefly discusses the power required to overcome those forces, which are a cube function. Note that weight is not a part of any of the equations. For all practical purposes, it's simply not a factor.
http://snipurl.com/cx1x

Nuke did my dirty work. I wouldn't call it "dirty" work :) I just like having facts to back up my points. :D

Nuke did my dirty work. No guesswork involved here. Consider yourself educated now.
LOL. My goodness, should you increase your hat size now?

Honestly, I have little interest in the topic at hand, but decided to respond to a comment I still believe to be inaccurate - despite my education, or lack their of.

So now you've been provided facts to back up a statement I made, and you still think it's inaccurate.

I believe the moon is indeed made of cheese. I don't care what facts you throw at me.

Your lack of interest in this topic is made clear by the number of replies you've made in this thread. Is it too much to ask to admit when you're wrong? Or does your hat size prevent that?

So now you've been provided facts to back up a statement I made, and you still think it's inaccurate.
I believe your assertion that - and I quote: "Weight is irrelevant for top speed" - is inaccurate. It is, however, quite possible that it does not have as much effect as I assumed. I have admitted quite clearly that I am in no way an expert on such things, nor have I ever bothered to find out. Nor will I likely look into it anymore. It simply means very little to me.

I believe the moon is indeed made of cheese. I don't care what facts you throw at me.
Hey, now that helps!

Your lack of interest in this topic is made clear by the number of replies you've made in this thread.
LOL. Your assumption about what has inspired me to reply is quite incorrect.

Is it too much to ask to admit when you're wrong?
Kindly see my last post (or was it two posts ago?), and my statement above.

Or does your hat size prevent that?
7 1/4. Has been for many years. Likely will be for many more. But then again, I don't believe I've ever told your (or anyone else) that I have just given them an "education" on the internet. That's to say that I haven't been right from time to time when others or wrong, but when this does happen, I've found that there is never a need to pat myself on the back.

Know what I mean?

I believe your assertion that - and I quote: "Weight is irrelevant for top speed" - is inaccurate. Assuming *reasonable* limits on weight increase, and not your silly hypothetical, weight is indeed irrelevant for top speed. You can believe whatever you wish to believe -- the facts say that your belief is misguided.

Ok. Define "reasonable." Or consider me silly and misguided. I have no issues either way. :)

Ok. Define "reasonable." Or consider me silly and misguided. I have no issues either way. :)As I've already said in a prevous post:
What's the aerodynamic force, ignoring rolling resistance, required to move a Vette through the air at 200 mph? About 450 lbs, while the rolling resistance for a car with DOUBLE the weight is only about a 40 lb difference in force required. Insignificant.
http://snipurl.com/cx23

So, concerning a 3000 Vette vs. a 6000 lb Vette, the difference in top speed is insignificant, therefore, a weight doubling is insignificant when discussing top speed and street cars.

A doubling of weight, as improbable as that may be, is reasonable. Asking if a 30,000 lb Vette would have the same top speed as a 3,000 lb Vette, other factors being equal, is not reasonable.

Ok. So help me out here. Everything else being equal (power, gearing, aerodynamics), what would be the top speed difference (in MPH, please) of a car weighing 3000 vs one weighing 3900 lbs. Pick whatever power and drag you wish.

Thanks. :)

Roll resistance power (approximate) = weight * 0.013 * mph / 375
Air drag resistance power (approximate) = fA * Cd * 0.003 * mph^3 / 375

Car A weighs 3000 lbs
Car B weighs 3900 lbs

3000 lbs * 0.013 * 200 mph / 375 = 20.8 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 / 375 = 384 lbs force to overcome air resistance
Or 404.8 lbs total force

3900 lbs * 0.013 * 200 mph / 375 = 27.04 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 /375 = 384 lbs force to overcome air resistance
Or 411.04 lbs total force

That's approximately 1% more power required for the 3900 lb car vs. the 3000 lb car, shown by 411/405=1.015. Since speed is proportional to the cube root of power, the cube root of 1 is 1. In other words, speed will decrease by about 1%, or 2 mph.

Bottom line is that the 3000 lb car will go 200 mph, the 3900 lb car will go 198 mph, all other factors being equal. You may disagree, but I call a 1% difference in top speed insiginificant.

BTW, I know you didn't ask for it, but comparing a 6000 lb car vs. a 3000 lb car...
6000 lbs * 0.013 * 200 mph / 375 = 41.6 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 / 375 = 384 lbs force to overcome air resistance
Or 425.6 lbs total force, or about 5% more power. Again using the speed vs. power proportion, speed will decrease about 1.7%, or 3.4 mph. In other words, a car that weighs twice as much as another car, if all other factors are equal (gearing, horsepower, wheels, etc.) the light car will do 200 mph and twice as heavy car will do 196.6 mph.

You're quite incorrect. First of all, "ergonomics" has absolutely NOTHING to do with top speed. You apparently have no idea what ergonomics even means. Look it up. Lastly, weight has little to no effect on top speed. Weight affects accleration rate, but not top speed.

The friction from the air is so enormous compared to other forces (remember, it's a cube function) that the minor increase in wheel and bearing friction due to weight increase is negligible. If you think otherwise, you simply have no clue about the physics involved.

You are absolutely right. Don't worry about anybody that argues with you. They are wrong about this.

Roll resistance power (approximate) = weight * 0.013 * mph / 375
Air drag resistance power (approximate) = fA * Cd * 0.003 * mph^3 / 375

Car A weighs 3000 lbs
Car B weighs 3900 lbs

3000 lbs * 0.013 * 200 mph / 375 = 20.8 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 / 375 = 384 lbs force to overcome air resistance
Or 404.8 lbs total force

3900 lbs * 0.013 * 200 mph / 375 = 27.04 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 /375 = 384 lbs force to overcome air resistance
Or 411.04 lbs total force

That's approximately 1% more power required for the 3900 lb car vs. the 3000 lb car, shown by 411/405=1.015. Since speed is proportional to the cube root of power, the cube root of 1 is 1. In other words, speed will decrease by about 1%, or 2 mph.

Bottom line is that the 3000 lb car will go 200 mph, the 3900 lb car will go 198 mph, all other factors being equal. You may disagree, but I call a 1% difference in top speed insiginificant.

BTW, I know you didn't ask for it, but comparing a 6000 lb car vs. a 3000 lb car...
6000 lbs * 0.013 * 200 mph / 375 = 41.6 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 / 375 = 384 lbs force to overcome air resistance
Or 425.6 lbs total force, or about 5% more power. Again using the speed vs. power proportion, speed will decrease about 1.7%, or 3.4 mph. In other words, a car that weighs twice as much as another car, if all other factors are equal (gearing, horsepower, wheels, etc.) the light car will do 200 mph and twice as heavy car will do 196.6 mph.

2 (or 3, or even 4) mph would certainly be fairly insignificant (I view irrelevant a bit differently - perhaps its my test director background?) in the eyes of most when talking about such a high top speed - mine included. So I suppose that my earlier statement - "if there is a difference, then that difference would apply to a much smaller extreme (ie..900 lbs), though how much would quite possibly be very minor" - was safe and correct.

Thanks. :)

So I suppose that my earlier statement.... was safe and correct.

But I thought you'd never pat yourself on the back? :confused:

:rolleyes:

Like I said, you are fighting wind resistance more than weight when you get up around the 200mph mark. And sure as ****, I'm still correct too.

But I thought you'd never pat yourself on the back? :confused:
LOL. The "confused" smiley is appropriate. If you cannot tell the difference between my statement and your "Consider yourself educated now" statement, well, then you just go right on posting confused and rolleyes looks. :)

And sure as ****, I'm still correct too.
Ok. Stranger things have happened.

:cz28:

You still patted yourself on the back, my statement notwithstanding. It doesn't bother me if you do. But don't act holier than thou and claim you would never do it, because you just did.

Yessir, I'll definately take your advise (or was that an order?) under advisement. And you go right on thinking it the same. Please. :)

or lack their of.Now who's "of" might that belong to? :confused:

LOL. Kindly pardon my incorrect use of the word "their". Please replace the word "their" with the word "there", as this shall make it more correct. While we're at it, should "there of" be hyphenated?

And of course, I was talking about myself. :)

Thereof should not be hyphenated, it should be spelled as I did in this sentence. ;)

LOL. Oh my, I best quit with my silliness before I get two...errr...to.....errr....too carried away.

Ya'll have a wonderful evening. :)

Roll resistance power (approximate) = weight * 0.013 * mph / 375
Air drag resistance power (approximate) = fA * Cd * 0.003 * mph^3 / 375

Car A weighs 3000 lbs
Car B weighs 3900 lbs

3000 lbs * 0.013 * 200 mph / 375 = 20.8 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 / 375 = 384 lbs force to overcome air resistance
Or 404.8 lbs total force

3900 lbs * 0.013 * 200 mph / 375 = 27.04 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 /375 = 384 lbs force to overcome air resistance
Or 411.04 lbs total force

That's approximately 1% more power required for the 3900 lb car vs. the 3000 lb car, shown by 411/405=1.015. Since speed is proportional to the cube root of power, the cube root of 1 is 1. In other words, speed will decrease by about 1%, or 2 mph.

Bottom line is that the 3000 lb car will go 200 mph, the 3900 lb car will go 198 mph, all other factors being equal. You may disagree, but I call a 1% difference in top speed insiginificant.

BTW, I know you didn't ask for it, but comparing a 6000 lb car vs. a 3000 lb car...
6000 lbs * 0.013 * 200 mph / 375 = 41.6 lbs force to overcome roll resistance
20 sq ft * 0.30 * 0.003 * 200^3 / 375 = 384 lbs force to overcome air resistance
Or 425.6 lbs total force, or about 5% more power. Again using the speed vs. power proportion, speed will decrease about 1.7%, or 3.4 mph. In other words, a car that weighs twice as much as another car, if all other factors are equal (gearing, horsepower, wheels, etc.) the light car will do 200 mph and twice as heavy car will do 196.6 mph.

First Id like to say you did a very good job explaing it.
Second, I didnt mean to say ergonomics..LOL..I meant aerodynamics. :rolleyes:
But there is still a small difference between 198 and 200 ;)
Although a small diff its still a diff. Although its not as big a difference as I expected so I actually did get some kind of education from this.
Learn something new everyday.

Thanks for the compliment. I figured you meant aerodynamics, but just felt like tossing in a smartass comment :) but now I apologize to you for having done it. My intent was to let you all know that weight really is insignificant when talking about 200+ mph top speeds. Nearly 1000 lbs of weight difference and only 2 mph less top speed? Almost a meaningless difference.

Nuke, do you have a formula to figure out top speed based on weight, cd, frontal area, hp, etc? I would like to play around with it and see how accurate it is. :)

Just plug the formulas into a spreadsheet and let it do the number crunching, or you can rearrange the formulas to solve for mph instead of power. When you try to determine what's called "frontal area" it's not the front of the car. It's basically the entire area of the biggest part of the car. The roughly 20 square feet happens to be the fA of a C5 Corvette.

The original post also had a curiosity about relative fuel economy potential between the C6 and the SVT Cobra. A buddy of mine bought a brand new '03 SVT Cobra vert and I saw that the window sticker rated it at 22mpg highway. I've seen weight figures for that generation SVT Cobra verts tipping the scales in the neighborhood of a portly 3700lbs. Can you say pork? Hopefully the coupe version of the SVT Cobra is a tad less thirsty given its lighter weight compared to the vert. Now, many base C5 owners have bragged 29-30mpg from their cars and the LS1 f-bodies weren't far behind that, stock for stock, in economy. Anyone seen fuel economy figures for the C6. GM's power vs fuel economy history from the L98 through the LS1 has been remarkable. Synthesized with CAI and improved cat back exhaust my former '91 1LE Z could knock out 25mpg at 75mph. When the LT1's came out the power was up 30-40hp over the L98 and fuel economy was up approx. 1-2mpg as well. That trend continued with the advent of the LS1, more power and slightly better fuel economy than the LT1. Now obviously there has to be a point of diminishing returns. Has the LS2 reached that point? Not sure. But if the LS2 can put out its 400hp with on par fuel economy with the LS1, or perhaps a tad improvement, I'd have to call that a serious coup. Who'd ever thought 30 years ago that you could have 12 second 1320' performance and have 28-30mpg fuel economy out of the same car? My hats off to GM for pulling off that power vs fuel economy trend over the last 20 years. I said all that to speculate that the SVT Cobra won't be able touch the C6 in fuel economy. :cool:

Chevy rates the 2005 C6 LS2 Vette at 18/26 for the auto and 18/28 for the stick.
Chevy rated the 2004 C5 LS1 Vette at 18/25 for the auto and 19/28 for the stick.
Those numbers are close enough to be considered the same.

Pontiac rates the 2005 LS2 GTO at 16/21 for the auto and 17/25 for the stick.
Pontiac rated the 2004 LS1 GTO at 16/21 for the auto and 17/29 for the stick.
A4 numbers are identical - I have no clue why there is such a differenc in the M6 highway miles.

FYI....the 03 Cobra was rated at 16/22, while the 04 (with no real changes) was 17/24. Go figure.

I think it is safe to say that the 07 Cobra won't get the same mileage as the much lighter C6 Vette, though it should still be close to the GTO.

Just plug the formulas into a spreadsheet and let it do the number crunching, or you can rearrange the formulas to solve for mph instead of power. When you try to determine what's called "frontal area" it's not the front of the car. It's basically the entire area of the biggest part of the car. The roughly 20 square feet happens to be the fA of a C5 Corvette.

What is the exact formula and unit of measure for each part of the formula?

This mpg twist to the topic reminds me of when I went to see a friend with a WRX wagon and let him drive my car through a very twisty section of road near his house. He knew my car had lots of horsepower compared to his Subie, but was very surprised when it handled pretty darn well through the section of road that he's driven so often that he said he could do it blind-folded. Then the crushing blow came when I told him that I got just shy of 30 mpg on a trip to Vegas and average 21. He said the best he's ever done in his car is the low 20's :D

These mpg figures from the epa are hard to swallow. I had a bone stock '93 Z28 auto with 3.23s. It got 14.7 in town. :eek: The epa must test cars while seriously babying the throttle.

I used to enjoy getting the reaction of folks when I told them that my N/A 99 Cobra with 4.56 gears got 28 mpg on the highway at 70 mph.

Being called a "liar" is the most sincere form of flattery. :)

Actually, I was wondering the spec of a Cobra R.. not an SVT. But thanx for the SVT's mpg specs :D

Actually, I was wondering the spec of a Cobra R.. not an SVT. But thanx for the SVT's mpg specs :D
The Cobra R's also come from SVT. However, we don't know when (or if) the next one will come out. The last one was the 2000 R. I don't remember for sure, but I believe it was rated at 13/18 or some horid numbers like that.

Per Edmunds, the Cobra-R was rated 13/18 mpg, but they got 14 mpg.
Edmunds Z06, Viper, Cobra-R comparison (http://www.edmunds.com/insideline/do/Drives/Comparos/articleId=45197/pageId=3357)

Per Edmunds, the Cobra-R was rated 13/18 mpg, but they got 14 mpg.


Yep, the epa is optimistic as usual. Check out the epa figures vs. what they actually got for the Viper and the Vette. :eek: The epa should have a disclaimer that reads, "Our figures obtained with Grandma driving."

Yep, the epa is optimistic as usual. Check out the epa figures vs. what they actually got for the Viper and the Vette. :eek: The epa should have a disclaimer that reads, "Our figures obtained with Grandma driving."
I know a guy with a vette that swears to 30MPG " LS1"
My LS1, before I started modding it got 29+ on the highway" when i wasnt beating it to death" I got over 400MPG on a tank form florida to here using my AC half the time. Drove it pretty easy though.
The LT1 never got good gas milage. That thing Loves its gas. The MPG on the highway stock was about 25. Best I ever got was 27 but the was not often. In the city it fricking hogs it like there is a whole in the tank.
The LS1 cammed gets better MPG then the LT1 does. :rolleyes:

These mpg figures from the epa are hard to swallow. I had a bone stock '93 Z28 auto with 3.23s. It got 14.7 in town. :eek: The epa must test cars while seriously babying the throttle.

I saw a report on the way they test cars for mpg and how usless it was for the normal drive and that they should change it, simulated curve this and percent throttle that. It's possible for some cars to have an advantage in the mgp tests that they don't really have on the street. I seem to remember the article saying Honda really milked/cheated their numbers compared to actual mpg results. The other thing to keep in mind is that the skip shift from first to fourth was only done by GM to sneak around the gas guzzler tax.

I read that GM had a rule that no car could have the gas guzzler tax therefore CAGS was introduced.