Unveiled: 2012 Audi R8 e-tron confirmed

Ladamaha

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I failed to do the math, but I assume 500 rpm is right if Germans say so.

Suppose the peak rpm actually was 500 rpm. Why would it matter with an electrical motor? You put the pedal down and it goes. It's not like a diesel where you have to be changing gears all the time because you can't accelerate because the effective rpm range is so short.
 

shad_68

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I failed to do the math, but I assume 500 rpm is right if Germans say so.

Suppose the peak rpm actually was 500 rpm. Why would it matter with an electrical motor? You put the pedal down and it goes. It's not like a diesel where you have to be changing gears all the time because you can't accelerate because the effective rpm range is so short.

Electric motors usually don't use a gearbox, so how fast you're going directly depends on the motor's rpm.


That said, I think that someone, somewhere made a mistake and added a 0 too much. 450Nm sounds much more likely.
 

Labcoatguy

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It has motors at all four wheels, so it's not an unlikely figure for all four motors put together. Heck, the Prius's electric motor makes 400 N-m of torque by itself, and it's not a very big one. What they really need to do is perfect a high-torque CVT to match these motors, to minimize the frictional losses that all engines have at high RPM, so they don't have to be spinning at >10k RPM at very high speeds.
 

Ladamaha

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Electric motors usually don't use a gearbox, so how fast you're going directly depends on the motor's rpm.


That said, I think that someone, somewhere made a mistake and added a 0 too much. 450Nm sounds much more likely.

It's not a typo it seems. More like twisting the truth.

from http://www.autoblog.com/2009/12/03/audi-twists-e-tron-3319-lb-ft-torque-rating/ The team at Automobile Magazine, initially duped like everyone else, has recognized that Audi was quoting torque measured at the wheels, not at the output shaft ? the industry standard. Measuring torque at the wheels takes the multiplication effect of the transmission and final drive gears into account. The resulting figures are generally ten-fold of what they would be at the crank (meaning cars like a 3.6-liter Chevrolet Malibu packs a similar 3,115 lb-ft of torque). Audi's e-tron torque figures are not exactly dishonest, but they are using a completely different evaluation without making mention of it in the press release. Long story short, Automobile estimates the e-tron makes about 252 lb-ft of torque, or a bit less than the Tesla Roadster's 273 lb-ft.

They are lying about the tq figure, it's actually about 1/10th of what they reported.

You should have explained!
 
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the Interceptor

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Since there is no transmission involved as far as I know, isn't the torque at the output shaft the same as on the wheel?
 

Labcoatguy

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Since there is no transmission involved as far as I know, isn't the torque at the output shaft the same as on the wheel?

It is, and since the Tesla has a 1-speed gearbox as opposed to no gearbox, without knowing the ratio of that single gear, it's not a valid comparison.
 

MacGuffin

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They should think about a different name, when they wanna sell it in French language countries...
 

klankymen

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They should think about a different name, when they wanna sell it in French language countries...

Fuck the french, they're only gonna set them on fire.

Well.... for that matter, so are you northern Germans.... :lol:
 

MacGuffin

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Yeah, we're all the same. Like the Bavarians and the Austrians are just the same :p
 

jetsetter

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I think it is better looking than the R8.
 

narf

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Measuring at the wheels does change stuff quite a bit :D

Taking the 430Nm of the V8 R8, its 1st gear ratio of 4.373 and its drive ratio of 3.462 you'd get a maximum of 6510Nm, assuming an ideal lossless gearbox.

The V10 delivers 100Nm more, assuming same ratios that would be 8023Nm at the wheels.
 

shad_68

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What they really need to do is perfect a high-torque CVT to match these motors, to minimize the frictional losses that all engines have at high RPM, so they don't have to be spinning at >10k RPM at very high speeds.

The simplest (and most common) type of electric motor has 1 (read: one [!]) moving part, so mechanical losses are already minimal compared to ICE engines and transmissions. I think if anything, adding a CVT would mean more losses. Not to mention that you'd basically need four transmissions, one for each motor/wheel.
 

Labcoatguy

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Measuring at the wheels does change stuff quite a bit :D

Taking the 430Nm of the V8 R8, its 1st gear ratio of 4.373 and its drive ratio of 3.462 you'd get a maximum of 6510Nm, assuming an ideal lossless gearbox and a clutch dump at the engine's torque peak.

The V10 delivers 100Nm more, assuming same ratios that would be 8023Nm at the wheels.

The beauty of the electric drivetrain is that it's at peak torque all the way up to where it starts falling off. This is assuming the Tesla power curve posted earlier in this thread is representative of all electric cars, but considering that there aren't any electrical equivalents to turbos or other supplementary tech, it probably is.

The simplest (and most common) type of electric motor has 1 (read: one [!]) moving part, so mechanical losses are already minimal compared to ICE engines and transmissions. I think if anything, adding a CVT would mean more losses. Not to mention that you'd basically need four transmissions, one for each motor/wheel.
Good point...it'd only make sense if there's a point where the losses from high-RPM operation outweigh the gains from a transmission. For high-speed cruising, it might make sense to have a push-button overdrive (remember those?) if that results in fewer losses. Hmm, maybe I need to go back to engineering...
 
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Magnet

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Looks like an Audi R8 and a 1960 Ford Galaxie were the ingredients in a nuclear experiment gone wrong.
 

klankymen

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Yeah, we're all the same. Like the Bavarians and the Austrians are just the same :p

Yeah, and just like all Americans are the same....

I'd rather be an ?si than a northerner though :lol:
 

Eunos_Cosmo

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The Tesla DOES have a gearbox. I don't know why everyone saying its just an electric motor bolted to the wheel hub.
 

Labcoatguy

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^The Audi has four motors bolted to the hubs ,or at least that's what they're planning.
 

JakeRadden

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^The Audi has four motors bolted to the hubs ,or at least that's what they're planning.

Doesn't that mean a fuckton of unsprung weight? Or am I just an idiot?
 
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