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Audi e-tron
Concept has four electric motors and a single battery pack

The world of electric and hybrid vehicles is progressing and growing at a rapid pace. While most people still think of hybrids and electric vehicles as low performance machines, there are an increasing number of high-performance electric vehicles being unveiled.

The first high performance EV was the Tesla Roadster with good performance thanks to the impressive torque of the electric motor. Audio has unveiled its latest concept car at the International Motor Show in Frankfurt called the Audi e-tron which just so happens to look like an electrified Audi R8.

The most impressive feature of the concept isn’t just its all-electric power train, but its tremendous amount of torque. Audi claims that the e-tron has a torque rating of  3,319.03 lb-ft. All that torque is generated by four individual electric motors situated at each wheel allowing the vehicle to be all-wheel drive.

The car has a total of 313 HP and promises to hit 60 mph in about 4.8 seconds. A more impressive number is that the car can go from about 37 mph to 74 mph in only 4.1 seconds. The all-electric range for the lithium-ion battery pack is 154 miles.

The EV is a large beast at 3,527 pounds and it measures in at 74.5-inches wide x 167.72-inches long and 48.43-inches tall with a wheelbase of 102.36-inches. The massive single battery pack alone weighs 1,036 pounds.

"We are trying to find a concept that requires no compromises," says Michael Dick, Member of the Board of Management of AUDI AG, Technical Development. "Electromobility means more to us than just electrifying conventional cars. Instead, we are dedicated to a holistic approach to all aspects of the topic."

Audi's American President called potential Volt buyers idiots not long ago and then quickly claimed he forgot what he said. There was only speculation surrounding the Audio EV concept at the time the comments were made.



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RE: <Drool>
By guacamojo on 9/15/2009 11:04:30 AM , Rating: 3
3,000 ft-lbs of torque is useless in a sports car. How do you couple it to the road? The car will just sit and burn rubber for a while, but you can do that with far less torque.

Torque is great when you're pulling a boat up the ramp, but I don't think you're going to do that in your E-tron.

I'd bet that they got the torque for free when they spec'd the 300 hp electric motors, and the statistic sounded impressive.


RE: <Drool>
By Spuke on 9/15/2009 11:46:54 AM , Rating: 2
quote:
3,000 ft-lbs of torque is useless in a sports car. How do you couple it to the road?
With todays tires, you don't. The torque would be severely limited in reality. BTW, I heard rumors of this car for the past two months or so. The rumors were an actual electric R8. But it turns out it's just a concept car with an R8-like body.


RE: <Drool>
By theapparition on 9/15/2009 3:16:32 PM , Rating: 4
Not at all true.

Take an old C5 Corvette, with only approximately 360ft-lbs. Multiply that by 3.06 for first gear and 3.42 for differential gear. That's a torque multiplier of 10.46 which is a total of ~3800ft-lbs at the rear wheels.

Not at all much different. Also explains why 0-60 times are so similar to a C5. A C6 would even be higher in the 4500ft-lbs range.

Quite a bit of difference between engine torque and wheel torque.


RE: <Drool>
By Spuke on 9/16/2009 11:38:06 AM , Rating: 3
quote:
Quite a bit of difference between engine torque and wheel torque.
Then what does a Dynojet measure?


RE: <Drool>
By theapparition on 9/16/2009 12:57:10 PM , Rating: 2
Have you ever run a Dynojet?

I have.

You have to enter those parameters in when stating the pull. For automatics, it uses the ODB port to determine which gear you're in.

When an engine is rated for torque and power, per the SAE standard, it is tested on an engine stand, not in a car.

It is a misnomer that when gearheads (like myself) rate cars with rwhp and rwtq, it is really engine hp and torque accounting for drivetrain losses.


RE: <Drool>
By Zoomer on 9/16/2009 6:30:23 PM , Rating: 2
Since the motors are at the wheels with no drivetrain, wouldn't engine torque = wheel torque?


RE: <Drool>
By theapparition on 9/17/2009 7:45:38 AM , Rating: 2
No. The wheel torque in a car with an ICE will be approximately 10x that of the engine itself. (All depends on the gearing in the transmission and differential, but 10x is decent 1st gear average.)

Wheel torque in a car with a motor mounted in the hub will be equal to the torque rating of the motor.

They are making this out to sound like something special, when it's really not. Where it does differ is the motors delivery of torque. Full torque is available at almost 0 RPM, while an ICE reaches max torque at a much higher RPM. That is why it is essential to drop the clutch (or use a high stalled auto) at the RPM where most torque is delivered for the best launch.


RE: <Drool>
By Spuke on 9/17/2009 1:31:20 PM , Rating: 2
quote:
Have you ever run a Dynojet?
I have not but that's why I'm asking. When you get a graph from a dyno, the torque rating isn't 4500 lb-ft (or whatever ridiculously high number). Maybe this discussion of torque multiplication is confusing me but I always thought that the actual torque number when a car is dyno'd was the result of the gearbox multiplication. My car would make say 220 lb-ft at the wheels on a Dynojet not 3000 lb-ft.


RE: <Drool>
By theapparition on 9/17/2009 3:58:35 PM , Rating: 2
No. It measures that high number and then back-calculates through input parameters to determine theoretical engine torque.

That's why I stated before the the concept of rwtq is flawed, yet often quoted (hell, even by myself). Yet what is being delivered to the tires is quite different.

In fact, dynojets don't even measure the engine RPM on older cars, rather use the tire diameter and tire RPM to generate those graphs.

For a simple ballpark figure, take the engine power and divide it by tire RPM. Power = Torque * RPM/5252.

So if an engine is developing 300hp at 6000RPM, and there is a 10x reduction through gearing, than the torque being delivered is 300hp*5252*(6000RPM/10) = 2626ft-lbs.

Pretty simple, and also requires that a dynojet knows what size rear differential and what gear the car is being operated in. Otherwise the results are junk......and also how some unscrupulous tuners like to improve thier results.


RE: <Drool>
By AbsShek on 9/15/2009 12:05:44 PM , Rating: 3
Looks like it will need the torque to lug around the already heavy battery and motors... add in a boat and ur screwed...

pretty impressive acceleration times for such a heavy car though... i guess that's where the torque comes in...


RE: <Drool>
By andrinoaa on 9/15/2009 5:34:34 PM , Rating: 2
Maybe, you won't afford to buy one unless you sell the boat.
If you can afford one, you can afford a towing vehicle too! Yada yada yada


RE: <Drool>
By scrapsma54 on 9/15/2009 12:11:31 PM , Rating: 2
I am sure audi is designing a nice little independent variable gearboxes for the sunnuva guns, if their is such a thing as indestructible.


RE: <Drool>
By mcnabney on 9/17/2009 10:04:25 AM , Rating: 2
You do understand that having independent motors on each wheel eliminates the gearbox entirely?

I believe the Tesla only has two forward 'gears' and a reverse. You actually don't even need to use the second forward 'gear', since it is technically not a gear. The article should have also mentioned that by adding a heavy battery and four light motors you can also remove a heavy engine, transmission, axles, exhaust, fuel tank, and fuel weight.


RE: <Drool>
By Trippytiger on 9/19/2009 3:05:53 PM , Rating: 2
The Tesla Roadster is actually down to one gear now. The ratios they wanted to use in the transmission were very far apart, which caused components to break. So they settled for water cooling the electric motor to solve the overheating problem that the two-speed gearbox was meant to fix in the first place.


RE: <Drool>
By markitect on 9/15/2009 1:21:03 PM , Rating: 2
your missing the fact that if the engines are per wheel there is little or no transmission, Your car transmission probably multiplies your torque by 3-5 times what the engine is rated at when your in first gear.


RE: <Drool>
By theapparition on 9/15/2009 3:18:27 PM , Rating: 2
Engine and differential in a modern high performance car is closer to 9-12x multiplier.

So even more reinforcement.


RE: <Drool>
By Chemical Chris on 9/15/2009 1:31:18 PM , Rating: 5
quote:
37 mph to 74 mph in only 4.1 seconds

That is what torque gives you, 'passing power'. Instantaneous power at any rpm.
Also, with so much torque, less mechanical torque multiplication must be used, allowing the motor/gears to be smaller and simpler, important with a motor and gear pack at each wheel.
oversimplified idea: If you had 300lb-ft and and 300hp, you would need gears to get the power to the road. with 3000lb-ft and 300hp, no gears would be necessary. Remember horsepower = (torque * rpm) /5252. So, if two engines have 300hp, but one has 10x the torque, it will have 10x the power per rpm/would have fewer rpm's to go through to get to peak power. The current R8 has a first gear ratio of 4.37, sixth is 0.93, final drive is 3.71. Torque is 317lb-ft from 4.5-6Krpm. Therefore, the wheels see 5139lb-ft in first, 1093lb-ft in sixth.
Im starting to rant, so Ill end now...

ChemC


RE: <Drool>
By fic2 on 9/15/2009 1:33:16 PM , Rating: 2
quote:
3,000 ft-lbs of torque is useless in a sports car. How do you couple it to the road? The car will just sit and burn rubber for a while, but you can do that with far less torque.


It's pretty easy to program the "gearing" so that the tires don't burn rubber. Tesla already does this. They take apply max power until the tires slip, then back off. Rinse, repeat.


RE: <Drool>
By Spuke on 9/15/09, Rating: 0
RE: <Drool>
By Amiga500 on 9/15/2009 2:23:32 PM , Rating: 2
Read about gearing and torque multiplication.


RE: <Drool>
By theapparition on 9/15/2009 3:27:12 PM , Rating: 3
No clue where you came up with this number.

Not to beat a dead horse, but that 3000ft-lbs is divided by each tire, or 750ft-lbs/tire.
A C5 would have approx 1800ft-lbs to each of the rear wheels (assming posi traction), and while you can get some slippage in a base C5, it is minimal and well within the capability of the stock run-crap tires they used to put on there. Add decent rubber, and you're fine. A LS3 C6 would even put more down, approx 2200ft-lbs per tire, and that is fine as well.

Go to R compound tires and even 4000ft-lbs is a non-issue at the track. Take that a step further to wide slicks and that number goes up further. My C5 drag car puts out 9000ft-lbs at the wheels! Hoosier slicks have never disappointed me.

So net effect is this car would actually be slower than most modern Corvettes, Porshes, and even ricer STi's while tires wouldn't even be an issue. A fact that the released performance numbers confirm, despite the sensationalist headline.


RE: <Drool>
By Spuke on 9/16/2009 11:39:38 AM , Rating: 2
quote:
A C5 would have approx 1800ft-lbs to each of the rear wheels
Again, if a C5 has 1800 lb-ft of torque at the rear wheels, what does a Dynojet measure?


RE: <Drool>
By Spuke on 9/16/2009 11:41:34 AM , Rating: 2
quote:
Go to R compound tires and even 4000ft-lbs is a non-issue at the track. Take that a step further to wide slicks and that number goes up further.
I'm not talking about specialty tires, I'm talking about tires are put on street cars from the factory which 99.9% of the population will be using. A set of Michelin PS2's ain't putting down 3000 lb-ft to the pavement without electronic nannies.


RE: <Drool>
By theapparition on 9/16/2009 1:06:49 PM , Rating: 2
Michelin P/S 2 (great tire BTW) come in various sizes, including 335 width. Do you actually mean to imply that a P/S 2 in a 335 coudn't handle more than a similar 195 width. There are quite a wide variety of P/S 2 tires sold on cars, but since we are talking about sports cars, yes, I believe they are 335 P/S 2's on the ZR1. So a blanket statement that 99.9% of tires couldn't hold xxxx torque is pretty misleading.

Weight of the car, contact patch, and rubber compound all contribute to the amount of friction force that the tire is capable of.

Now, keep in mind, that torque I talked about is at the shaft, you now have to divide that by the moment arm (also known as tire radius) to find out what the pavement/rubber interface force will be.

You can disbelieve all you want, but fact remains that quoted performance numbers match closely towards conventional gas engine cars of 10x "less" rated torque.


RE: <Drool>
By Spuke on 9/17/2009 1:36:31 PM , Rating: 2
quote:
You can disbelieve all you want, but fact remains that quoted performance numbers match closely towards conventional gas engine cars of 10x "less" rated torque.
it's not about disbelief, it's about you guys not explaining yourselves. I'm asking the questions to get an explanation. When I take my car to the dyno, the sheet doesn't say I have 3000 lb-ft it says I have 220. Yet you guys are saying that a C5 actually puts down X 1000 lb-ft of torque to the road. If that is so, what does a Dynojet measure?


RE: <Drool>
By theapparition on 9/17/2009 4:03:07 PM , Rating: 2
Answered above.


RE: <Drool>
By 91TTZ on 9/20/2009 9:35:53 PM , Rating: 2
quote:
When I take my car to the dyno, the sheet doesn't say I have 3000 lb-ft it says I have 220. Yet you guys are saying that a C5 actually puts down X 1000 lb-ft of torque to the road. If that is so, what does a Dynojet measure?


I think that the majority of people replying in this thread have little to no knowledge of how cars or dyno's work.

I'll do my best to answer your question:

When you dyno your car they make you put it in 4th gear to do the pull. They do this to get it as close to a 1:1 ratio through the tranny as possible. From the spark plug clamp they know what RPM your engine is turning, and the dyno computer already knows what RPM the drum is turning. It's all math from there. They aren't going to show you a 10x multiplication because your ratio is about 1:1 during the pull. In addition, even if you pulled it in 1st gear and you had a 10x gearing multiple, the dyno computer would divide it by some ratio between engine rpm and drum rpm.


RE: <Drool>
By 91TTZ on 9/20/2009 9:40:59 PM , Rating: 2
quote:
When I take my car to the dyno, the sheet doesn't say I have 3000 lb-ft it says I have 220. Yet you guys are saying that a C5 actually puts down X 1000 lb-ft of torque to the road. If that is so, what does a Dynojet measure?


I think that the majority of people replying in this thread have little to no knowledge of how cars or dyno's work.

I'll do my best to answer your question:

When you dyno your car they make you put it in 4th gear to do the pull. They do this to get it as close to a 1:1 ratio through the tranny as possible. From the spark plug clamp they know what RPM your engine is turning, and the dyno computer already knows what RPM the drum is turning. It's all math from there. They aren't going to show you a 10x multiplication because your ratio is about 1:1 during the pull. In addition, even if you pulled it in 1st gear and you had a 10x gearing multiple, the dyno computer would divide it by some ratio between engine rpm and drum rpm.


RE: <Drool>
By Spuke on 9/17/2009 1:43:20 PM , Rating: 2
You said,
quote:
Go to R compound tires and even 4000ft-lbs is a non-issue at the track. T

I said,
quote:
I'm not talking about specialty tires, I'm talking about tires are put on street cars from the factory


Michelin PS2's are regular street tires and I have yet to see a twin turbo Viper with 1000+ lb-ft of torque NOT smoke a set. I have yet to see a Solstice with 300 lb-ft NOT smoke a set. FACT, todays STREET tires can't hold the torque that this Audi will will be putting down, especially at that super low rpm, without electronic nannies.


RE: <Drool>
By theapparition on 9/17/2009 4:01:39 PM , Rating: 2
If you put a wide enough tire on any car, it will hold fine.

I only took issue with your 280ft-lb comment that seemed to be pulled from air. Can you supply some sort of data that supports a street tires limit of grip at 280ft-lbs. If not, than admit it was just a WAG.


RE: <Drool>
By zephyrprime on 9/15/2009 5:51:41 PM , Rating: 2
quote:
I'd bet that they got the torque for free when they spec'd the 300 hp electric motors, and the statistic sounded impressive.
Probably. All the EV's of the future will have super high torque by modern standards. This Audi is leader of the pack for now but I remember reading an article just the other day about a new electric motor design that doubles torque.


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