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Audi Q5

Audi A8
Audi A6, A8, and Q5 to get TDI power

Audi is no stranger to diesel engines. In Europe and other world markets, Audi has a number of TDI options available for consumers for the many models in its lineup. In the United States, however, those looking for a diesel Audi can only choose from the tiny A3 TDI or the mammoth Q7 TDI.

Now, according to Fourtitude, Audi is looking to spread a bit more TDI lovin' to customers in the U.S. The company just announced today that it would bring its 3.0-liter TDI engine to the A6 sedan, A8 sedan, and Q5 small crossover vehicle.

Those still holding out for a TDI engine in the popular A4 sedan and Avant will have to wait a little longer. Audi officials say that since the current A4 is already in the "advanced stages" of its lifecycle, that U.S. customers will have to wait until the next generation A4 arrives in a few years. 

The 3.0-liter TDI coming to the A6, A8, and Q5 is already available in the Q7 TDI. It generates a respectable 225hp at 3,750 rpm and a gargantuan 406 lb-ft of torque at 1,750 rpm in that application. The engine is capable of giving the 5,567-pound crossover EPA ratings of 17 mpg in the city and 25 mpg on the highway. 

The three new TDI models are much lighter which should make the fuel economy gains even more impressive compared to their gasoline engine counterparts.

There were recent reports that General Motors is looking to bring a diesel engine to the U.S. market for its Cruze compact instead of going for a fully-fledged hybrid model.



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RE: Good.
By Motoman on 3/8/2011 9:43:59 PM , Rating: 4
Gearing...yes and no. While proper gearing makes *almost* any engine effective, a weak motor with proper gearing that takes 30 seconds to get from 0 to 60mph isn't going to be very useful.

As for your second point...I see what you did there, but I am guessing you are twisting the math around to make torque look like a derivative of HP. It's not - HP is a derivative of torque.

Torque x RPM / 5252 = HP <-- that's the way that is normally stated.

If you play with the numbers you can see how high RPM motors can post big HP numbers but have little effective torque...and the other way around. While HP may be flashy on a dyno, torque is what really matters for the vast majority of every day applications of motoring.


RE: Good.
By Calin on 3/9/2011 2:49:09 AM , Rating: 3
Just as a side note:
HP is maximum HP of the engine, while torque is the maximum torque of the engine.
As such, a diesel engine with flat torque curve between 2000 and 4000 rpm and max power of 100HP at 4000 rpm will have 50HP available at 2000rpm.
Meanwhile, a non-turbo, typical gasoline engine of 200HP, with max power at 6000rpm and flat torque from 4000 to 6000 rpm (and, let's say, half the 4000rpm torque at 2000rpm) will give me about 133HP at 4000rpm and some 33HP at 2000rpm.
So, that 100HP turbo diesel engine will give me more power in the idle to some 3000 rpm range. If you're driving mostly in that range, and can learn the fact that revving doesn't help, diesel is good for you - it's more expensive initially.
On the other side, you really doesn't need the entire power of the engine except when forcing to pass another car/truck (but then you really really want to end the passing as fast as possible). In this case, with downshifting, that 200HP gasoline engine will really offer you power.

So, that's the idea in short - power and torque are related, but they're not the maximum values that everyone likes to give - they varies based on rpm and a diesel engine will have quite a bit of rpm range where it will soundly beat a similar gasoline engine (be it similar in displacement, maximum power, maximum torque or price). That's right, a turbo diesel 2 liter engine still has a rpm range where it's superior to a 3 liter gasoline (or turbo gasoline) engine. It all depends where you draw the line between what you NEED and what you like.


RE: Good.
By Spuke on 3/9/2011 1:34:47 PM , Rating: 2
quote:
That's right, a turbo diesel 2 liter engine still has a rpm range where it's superior to a 3 liter gasoline (or turbo gasoline) engine. It all depends where you draw the line between what you NEED and what you like.
All things being equal including HP, yes, the diesel will be quicker. But a 100hp diesel will NOT be quicker than a 150hp gas engine. no matter the difference in torque. Compare an equivalently equipped BMW 335i to a 335d. The 335i is quicker despite the 335d's 400+ lb-ft of torque. The difference, if all else is equal, is HP.

The best thing about diesels is big torque at low rpms. Great for trucks that pull/haul lots of weight. Makes for much quicker acceleration and better fuel economy under load. For cars, it's just fuel economy and the big torque down low feels good when you're driving.


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