Are Diesels The Future For Luxury Sport Sedans? Audi Says Yes
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Charlie271
New member
A no-brainer for me: I've had my 2014 Audi A6 TDI for a month now. Couldn't ask for a better car. It's comfortable but also maneuverable and quick.
So far I get 30-32 mpg in town and 40-44 on the highway. (a tailwind helps a lot!)
So far I get 30-32 mpg in town and 40-44 on the highway. (a tailwind helps a lot!)
IndigoBlueWagon
TDIClub Enthusiast, Principal IDParts, Vendor , w/
Yawn. Something like 70% of luxury cars sold in Europe are diesels. They're coming here because of FE mandates, no other reason. Not that it's a bad thing by any means, but this article is just another lazy re-hash of a press release, I'm sure.
Although the 3.0 TDI is a nice engine, it has nearly 100 HP less than the 3.0 supercharged gasoline engine that they call "equivalent." I'm sure torque is greater in the TDI, but HP wins races.
As an aside, I made a run to the supermarket in my Mercedes diesel. Still a pretty nice luxury car, and it's 20 years old.
Although the 3.0 TDI is a nice engine, it has nearly 100 HP less than the 3.0 supercharged gasoline engine that they call "equivalent." I'm sure torque is greater in the TDI, but HP wins races.
As an aside, I made a run to the supermarket in my Mercedes diesel. Still a pretty nice luxury car, and it's 20 years old.
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mrspindlelegs
Active member
I seriously doubt anybody buys an Audi A6 to go racing.
wxman
Veteran Member
According to manufacturer's data (http://www.audiusa.com/models#), the 2014 Audi A6 TDI has a 5.5 second 0-60 mph rating while the 2014 A6 3.0 TFSI has a 5.3 second 0-60 mph rating.
The 0-60 mph performance for the 2014 A7 is 5.5 seconds for the TDI and 5.4 seconds for the 3.0 TFSI. Not very significant.
There's a 35% (A6) and 38% (A7) fuel mileage advantage for the TDI in the official EPA combined mileage and 21% and 24% advantage respectively on a mpg gasoline equivalent (mpgge) basis, even with EPA's acknowledgement that the 5-cycle test tends to significantly underestimates the real-world mileage of diesels.
The 0-60 mph performance for the 2014 A7 is 5.5 seconds for the TDI and 5.4 seconds for the 3.0 TFSI. Not very significant.
There's a 35% (A6) and 38% (A7) fuel mileage advantage for the TDI in the official EPA combined mileage and 21% and 24% advantage respectively on a mpg gasoline equivalent (mpgge) basis, even with EPA's acknowledgement that the 5-cycle test tends to significantly underestimates the real-world mileage of diesels.
The 3.0T is quite a bit stronger than the US 3.0 TDI, the difference will be more than just a tenth, especially as speeds pick up. The 1/4 mile trap speed gap is significant. Here are two comparable A8 tests. The TDI will do fine but the 3.0T is stronger. The bi-turbo 3.0 TDI would be closer to sports sedan promise.
http://www.motortrend.com/roadtests/sedans/1307_2014_audi_a8_l_tdi_first_test/
http://www.motortrend.com/roadtests/sedans/1206_2013_audi_a8_l_first_test/
wxman
Veteran Member
Actually, the MT tests are closer between the A8L TDI and the A8L 3.0 TFSI than the Audi data (6.4 sec/5.5 sec, respectively, according to Audi, compared to 5.8 sec/5.3 sec, respectively, in the MT links).
There are currently no test data other than Audi for the A6 and A7 as far as I know.
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True, but you can see that the gap grows rapidly with speed.
DubFamily
Veteran Member
Likely true; but if you are buying an A6 or A8 to run 1/4 miles in then you are doing it wrong. 
For the purpose of actual day-to-day driving, the two engines will be nearly identical in performance, with a 35% plus advantage to the Diesel for economy.
For the purpose of actual day-to-day driving, the two engines will be nearly identical in performance, with a 35% plus advantage to the Diesel for economy.
Both are more than adequate I would assume but at the A8's price I would just upgrade to the V8 and embarrass almost any challenger. The A8 V8/S8 and W12 are pretty great at the quarter mile but MB just came out with the new S class with quite a bit of power in the base trim and we are talking about flagship sedans. But you are right most of them are driven pretty sedately.Likely true; but if you are buying an A6 or A8 to run 1/4 miles in then you are doing it wrong.
For the purpose of actual day-to-day driving, the two engines will be nearly identical in performance, with a 35% plus advantage to the Diesel for economy.
IndigoBlueWagon
TDIClub Enthusiast, Principal IDParts, Vendor , w/
Cars are way more powerful than they need to be in this market. In Europe Audi has a 2.0L TDI A8. And BMW has a 2.0L diesel 5-series. Both are more than quick enough for US driving, but they probably wouldn't sell here.
I spend a lot of time these days driving my Passat: with a mild tune it's probably making 100 HP. And I rarely have to floor it. My Mercedes has 119 HP in a heavier car, and it's plenty quick enough to stay out of trouble, although no one would call it fast.
Fact is, most drivers would be terrified to be in their cars when driven anywhere near their limits. By and large we're very gentle drivers.
I spend a lot of time these days driving my Passat: with a mild tune it's probably making 100 HP. And I rarely have to floor it. My Mercedes has 119 HP in a heavier car, and it's plenty quick enough to stay out of trouble, although no one would call it fast.
Fact is, most drivers would be terrified to be in their cars when driven anywhere near their limits. By and large we're very gentle drivers.
Here is another preview of A6/A7 TDIs with some good info.
"Audi has fitted the U.S. car with a slightly smaller compressor than the comparable European model to tweak the power curve, sacrificing autobahn power on the top end for low-end responsiveness."
I would have to agree with their final assessment though as I can see how luxury diesels make sense in Europe where fuel is double the price but in the US fuel is cheap enough (especially for those purchasing 60-70k price bracket) to complicate things.
"We like diesels. We like the big torque and the excellent real-world fuel economy. But the notion that anyone is buying a $60,000 sedan with a heavy environmental conscience or a pragmatic economic analysis is a stretch. Performance sells cars in this price range. Civilized and torquey as it is, the TDI engine doesn’t have the immediacy of the gas-fueled supercharged V-6, an engine that sets an industry standard for its instant throttle response, supreme linearity, and excellent power delivery. Paying more money for fewer thrills doesn’t make much sense here."
http://www.caranddriver.com/reviews/2014-audi-a6-a7-tdi-first-drive-review
"Audi has fitted the U.S. car with a slightly smaller compressor than the comparable European model to tweak the power curve, sacrificing autobahn power on the top end for low-end responsiveness."
I would have to agree with their final assessment though as I can see how luxury diesels make sense in Europe where fuel is double the price but in the US fuel is cheap enough (especially for those purchasing 60-70k price bracket) to complicate things.
"We like diesels. We like the big torque and the excellent real-world fuel economy. But the notion that anyone is buying a $60,000 sedan with a heavy environmental conscience or a pragmatic economic analysis is a stretch. Performance sells cars in this price range. Civilized and torquey as it is, the TDI engine doesn’t have the immediacy of the gas-fueled supercharged V-6, an engine that sets an industry standard for its instant throttle response, supreme linearity, and excellent power delivery. Paying more money for fewer thrills doesn’t make much sense here."
http://www.caranddriver.com/reviews/2014-audi-a6-a7-tdi-first-drive-review