I don't think that is 100% accurate. Even if the R8 would have 500 peak hp with an NA V10 it would not have the same horsepower under the curve due to the torque difference with an RS6 with a twin turbo V10.Originally Posted by Leadfoot
I don't think that is 100% accurate. Even if the R8 would have 500 peak hp with an NA V10 it would not have the same horsepower under the curve due to the torque difference with an RS6 with a twin turbo V10.
of course R8 will have different power than the new RS6 and different torque pikes because R8 will be normal aspirated V10 and RS6 bi-turbo V10, is the same engine but different construction!
A RS6 with 550hp would have a power to weight ratio of around 285hp/ton while the R8 should be around 300hp/ton. I know that is only a small difference but less frontal area should help the R8 maintain an advantage. If the RS6 is twin-turboed it will have a much better in-gear times when combined with it's auto gearbox.
But anyway they are two different cars in two totally different markets.
Search and you will find the truth.
I agree with RXBG- the R has a certain je ne sais qoi that makes it much more desirable and in a different league than the M6 and I am guessing that Audi will bring the V10 R8 to market with 500 bhp. The normally aspirated V10 will be much more reliable that the twin turbo RS6 engine and will be easier to keep cool.
The sound will be spine tingling.......
Good point. There is a lot more than HP to what makes a car run. In this case, though, the HP difference between those two models is a little more than you state. Just comparing the 330i and 325i, the 330i has not only higher horsepower (272 v 218 hp - which is a 40 kW difference but 54 more hp). It also has greater torque (315 v 250 Nm), thanks to a larger displacement engine (3.0 v 2.5l - both bore and stroke are bigger), and slightly different gearing for a lower final drive ratio. With all that increased power, torque and leverage, and only a little more weight, it is not surprising that the 330i accelerates significantly faster than the 325i. Not even close, in fact.
There's no substitute for displacement.
SoCal
Current: S6 (2007), A3 2.0T (2008), RX-7 (1995)
Previous Audi: RS6 (2003)
Horsepower was invented in 1872 by James Watt. He was working on steam engines for coal mines, and asked to be payed 1/3 of the savings the mine owners got from using his engines. As most mines used ponies to pull the coal up from the mine, he invented a unit that tells you how much work a coal mine pony does in a minute, during a 4h working shift. Work is; pulling up a weight at a certain speed. He then estimated that a horse was 50% stronger than a pony, and the horsepower was born. One horse is capable of 1hp of work.
When translated to an engine, you have to imagine that the engine is rotating a resisting force on a lever. The "work" that this requires is equal to the work that the horse does, when it pulls up a certain weight at a certain speed. An engine itself is a lever that rotates at a certain rpm. In an engine, horsepower is "(rpm x torque)/constant". The constant depends on the units you are using. Hp is never, ever, measured. It is calculated from torque at a certain rpm.
The problem:
So horsepower is the ability to produce force at a certain speed. The 'work' it can do. Two horses will pull up a weight twice as fast as one horse. Or a weight twice as heavy. And that's the problem with horsepower. You don't know if it's twice as fast, or twice as heavy. The number doesn't say.
With proper gearing, an engine that produces a lot of torque at a low rpm can perform just as well as one that produces a small amount of torque at a high rpm. In fact, if you factor in the air resistance, more torque will do better. But horsepower is calculated with rpms, and rpms are expressed in thousands (as opposed to torque). So the engine with low torque at high rpms will generate a bigger hp number. That's why bike engines get a high peak horsepower number from relatively small engines. But that doesn't mean these are powerful engines, b/c in a vehicle with the weight of a car they would be useless.
Especially the peak hp number has nothing to do with acceleration. You can get some vague idea of the powerband, assuming it has a powerband. If might as well be an engine that only produces torque at that particular rpm.
At half the rpm of the peak hp, the engine generates half the horsepowers (assuming torque is constant). The car will accelerate just as fast at that point, with only half the horspower.
What really matters is the torque curve. The 'powerband'. Peak numbers are useless. You want a lot of torque, over a lot of rpms. Hp combines these two numbers, but you don't know which is which.
Horsepower is a great marketing tool though. The bigger the number, the better the engine. And it makes people think it has the power of numerous horses.
The avarage horse manages about 15hp for short periods, and less than 1hp for long periods. That is the amount of weight it can pull up, measured over a certain distance, in a certain time. Compared to the imaginairy horse of James Watt.
In relation to this thread, you are discussion hp numbers as if they indicate the performance of the engine. They indicate the "work" the engine does, at a certain rpm. It tells you very little about how the engine will perform as part of the drivetrain in a certain vehicle. It gives you a vague idea at best.
Mazda MX-5 (Miata NB)
excellent work , man
i like your quote too. i might be nice to the first bmw i see today.
Past- A4, TT, S4
Present- R8 V10
Does anyone know if the V12 Diesel engine from the Q7 will fit into the R8? Especially considering Audi's current racing ethos.
PeterJohn,
Yes, very nicely said, and I like your tag line, too.
The main thing I like about my RS6 engine is the high flat power band... lots of torque over a wide range of RPMs. That, not the high horsepower, is what gives it the strong feel of raw power that just keeps on pulling.
When accelerating in any gear in any car, the driver feels torque, not horsepower. Period. I agree with you completely, and that was the main point behind my prior post on the 3-series BMW model comparison.
The push-back-in-the-seat feel is not always a reliable indicator of how fast the car is really accelerating...or, more precisely, of how long it can continue to accelerate (which results in top speed, where horsepower matters a great deal). Gearing, which is related to where on the power band peak torque occurs, also makes a difference. (Turbos and turbo lag further complicate this, but they don't change the physics.)
The constant in the formula, by the way, is 5252 (which is Mr. Watt's fault), so at 5252 rpm horsepower and torque are equal.
Horsepower = (Torque x RPM)/5252
So? Torque measures force (how much the car pulls). Horsepower measures, well, power (how long the car pulls).
It's better to make torque at high rpms than at low rpms, because you can take advantage of gearing. As engine speed rises, horsepower rises rapidly (and passes peak torque, crossing the torque curve) until torque falls off at the top end faster than the increase in rpms, and hp falls. In general, engines with higher peak horsepower produce greater torque at high rpms. With that, you can pull longer without needing to shift to maintain torque, so that helps acceleration. If a car lacks high end torque, then the driver needs to up-shift sooner, and more often, to take advantage of higher torque at lower rpms in the next gear. Acceleration suffers. So, horsepower influences acceleration and of course matters a great deal for top speed.
In short, I agree that peak torque and the shape of the power band matter much more than peak horsepower. But horsepower is still a useful measure of engine performance when taken in context.
Last edited by SoCal; February 14th, 2007 at 07:49. Reason: format for formula
SoCal
Current: S6 (2007), A3 2.0T (2008), RX-7 (1995)
Previous Audi: RS6 (2003)
What PeterJohn is talking about not only makes sense but it's one of the reasons why so many manufacturers are looking closely at the new Torotrack gearbox. It basically holds the maximum torque revs for acceleration, no gears as such. Or to put it another way, if to accerelated with a part throttle the engine would only need to rev to 1500rpm right from 0-100mph, just think how relaxing that would be.
I think you will all find this very interesting.
http://www.torotrak.com/automotive/cars/
Search and you will find the truth.
someone posted that M6 beats R8 at a drag race and on the circuit..yeah?really?how stupid is that?R8 is way more faster than the M6...7:55s on the biggest strongest meannest circuit of all time...the Nurbugring Nordschleiffe...M6 did in 8:07.76 152.041 km/h -- BMW M6, 507 PS/1761 kg, Prinz Luitpold von Bayern (AutoBild 02/06)...ahhh BMW with RWD to do an Audi?Yes and i'm a preast...
and also i would like to say that the new R8 will have definetely 500HP from the V10 5.2l or from the V12 TDI beastr with more torque than an small airplane
We get it, you hate BMW, but can you keep your language at a more adult level.someone posted that M6 beats R8 at a drag race and on the circuit..yeah?really?how stupid is that?R8 is way more faster than the M6...7:55s on the biggest strongest meannest circuit of all time...the Nurbugring Nordschleiffe...M6 did in 8:07.76 152.041 km/h -- BMW M6, 507 PS/1761 kg, Prinz Luitpold von Bayern (AutoBild 02/06)...ahhh BMW with RWD to do an Audi?Yes and i'm a preast...
and also i would like to say that the new R8 will have definetely 500HP from the V10 5.2l or from the V12 TDI beastr with more torque than an small airplane
And as far as i know, Frank Stipplers rekord is not official, the Official RS4 time set by Sport Auto 06/06 on the ring is 8.09 min.
And where did you get 7.55min time for the R8?
Wait untill Sport Auto drive it around the ring for a "officiall" time.
official time?hmm...that's the official time man..and bmw yes...really sucks...
set by who?
M!,
I couldn't agree more, I'm not a lover of Beemers but I still admire their design and commitment to rwd no matter how mislead it is.
Correct, the RS4's time is 8:09 as is the M6's. Both it's 7:58 and the R8's 7:55 are unofficial, but I am unsure if it was Stippler who drove the R8 to it's time.
Why read to much into these times anyway, they mean very little in the real world and not tell how easy the time was achieved. I doubt the R8v8 will match the M6 in acceleration, though the R8v10 will stand a better chance, but again it's a tall order.
Search and you will find the truth.
I agree.
R8 will have problem leaving M6 behind. M6 is killing fast over 100km/h.
rolling start R8 doesent match the M6. The M6 will not humiliate the R8, but it will be slitly faster no doubt about that.
Onlythe V10 will distroy the M6...
The v10 R8 won't destroy the M6 in a straight line if that is what you are getting at.
R8 even with the actuall V8 is destroying M6 but with the V10 it will humiliate M6 so nasty that M6 will cry like a baby...should i tell u again that 4WD is the best sport traction in the world and never ever loose power against super supraviration and burnin' tires like RWD?or i will say again...RS4 beat the crap M6 and R8 is 2sec faster than the RS4 so we all know what will happen when M6 will be against R8 on a test drive...humiliation will arrive...
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