The fairly miserly 2.0T engine is rated at 211hp; and nowhere stratospheric at 5800 rpm. The A4 Avant is like a 1/2 ton heavier than my JCW and rated at near the same HP. Can someone please explain how it gets from 0-60 in about 6.2 sec, which is pretty stupendous for 211hp in a car near 2 tons (in Avant form)? I know the rated torque is 245; but that part of the curve is only used in 1st gear when doing a WOT run... this is all based on MotorWeek's test that took 6.2 seconds: review: http://www.mpt.org/motorweek/reviews/rt2812b.shtml ; video: http://www.youtube.com/watch?v=Uq81iyP9UVc

- Is it purely gearing? ...it does take a really long time to get to 100mph, which comes well after the 1/4 mile mark after all. So it seems to have blown its load before hitting the century mark. (anyone know, does the A4 2.0T need to hit 3rd gear to hit 60mph?)

- Is it dramatic gains in drivetrain efficiency and shift speeds this past decade? It was some time around the middle of the past decade when I started seeing 3500lb cars with HP ratings in the 250 - 265 range getting to 60mph in 6 seconds. And I couldn't understand how. Faster shifting? Better torque converters (when it uses a slush-box)? Generally less parasitic losses in the transmissions?

I mean, in addition to my JCW I own a '98 MB C43 too. It was 302/302 hp/trq stock & would take every bit of 6 seconds to get from 0-60. And that car is something like 400 lbs lighter than the A4 Avant 2.0T. And I always blamed its transmission for its inability to make better use of its 302hp. [Many years back I did a 5.4L swap from a E55, so the car performs every bit I'd want now, so don't worry for me ].

So ... HTF does a 3850lb car w/only 211hp get from 0-60 in 6.2 seconds?! Does the above cover it, or am I missing something else?

 

Torque down low is what you need for acceleration. Horsepower is for top speed.

 

Well, torque IS HP ignoring whatever RPM it is being applied at. HP=Trq*RPM/5252 aka Trq=HP*5252/RPM after all. The relationship between Torque/HP/Gearing is an interesting one. If you want to keep a linear rate pulling a huge load up a hill, you want to operate the engine at the RPM of max torque. If you're running thru the gears to accelerate and reach top speed or a set distance (say 1/4 mile) in the least amount of time, the fastest you can get there is to shift around the max HP point, to ensure the range of RPMs you are using in a gear maximizes the area under the HP curve (yes, you get to make use of Integration you learned in your high-school or college calculus class, depending on when you took it). This is because moving the vehicle forward at ever increasing rate is a function of work, which is a function of HP, which is a function of torque at an RPM, so you need to make use that that range of engine's operation while passing from gear to gear to maximize transfer of that power to the contact patch. Download CarTest2000 and play with custom shift points on 1/4 mile runs if you don't believe that.

Regardless of that. For the weight and rated engine power that time to speed is still unimaginable just a few years ago. Find me any car near 10years or older with that weight and engine power that doesn't take near 7.5 seconds give or take a bit to get from 0-60. That's what I'm talking about.

Otherwise, instant twist translated to linear force @ the tire's contact patch is perfect to have off the line if you have the tires and grip to make use of it, especially w/the AWD. But that high level of torque down low doesn't do you any good by the time it up-shifts to 2nd gear; when it up-shifts the engine rpm usually only drops to about 4500rpm give or take. So it's vital that an engine hold that high level of torque up to near redline ... maybe that's what the 2.0T engine does?

The numbers don't seem to bear that out tho. The engine is rated @ 211hp @ 5800rpm; so from that point forward torque starts dropping off even faster than it had been from its peak down low so that the HP curve also starts dropping. That means Trq @ 5800rpm = 211*5252/5800 = 191ft-lb. Honestly, not all that high in a 3850lb vehicle. [!] Does the 2.0T engine have an over-boost Audi doesn't talk about?

In regards to making most of gearing. Most cars shift to 3rd just above 60mph; 0-60mph times are greatly longer when a car needs the time of another shift to 3rd before hitting 60mph so designers usually most always try to ensure any car that is supposed to be "performance oriented" doesn't need to shift to 3rd before hitting 60mph; so it reads well in the specs and car review tests. Very noticeable in my MB. Before the 6.2L AMG engine began getting used all Mercedes engines would blows their load early; great for all around driving, but less than everything it could be @ WOT vs if the engine produced max torque higher-up in the rev band.

So then I guess the 60ft times must be well under 2 seconds and Audi makes most of 1st gear getting to 40mph ridiculously fast?

I'm thinking that MotorWeek test has to be a fluke. Most all other tests I see are 6.5 or 6.6 sec. Especially now that the only option in the Avant is the 8-speed slush-box. I'm thinking that it may need a 2-3 shift to get to 60mph; haven't seen any reports of that yet, or table that states max speed in each gear yet.

 

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As a long time Audi owner, they are getting increasingly fast just via the tranny gearing. When you go from a a 6 speed auto to an 8 speed, you can increase total gear spread, effectively push 1st gear down and 8th gear way up for economy. At least on the 6 speed auto's, ZF (often the supplier to Audi and BMW for mid and bigger motors) says they can now do shifts in 0.1 second. Even a really good driver won't get to a tenth of a second on a stick. I also remember when Audi went from the 5 to the 6 speed auto's, car for car that pulled the better part of a second off their 0-60 times as another reference point.

Audi's with a longitudinal motor set up ike the A4 have WAY less torque steer than the Mini too (BTDT on both), so I expect the Audi can get the available power down better too, albeit yes Audi's have gotten very porky (as have most cars). And if you are talking Quattro that is basically NO torque steer and a Torsen front to back differential, so all stick, all the time.

Net, yes lots of it in the tranny gearing likely. Audi also does a good job w/ tuned manifolds for a broad torque curve. More room for that in the bigger-hood, front-to-rear-mounted Audi type set up than in a Mini underhood. You would have to pull the graphs on both motors to look that over.

 

Perhaps VW/Audi under rates their HP on the 2.0T.....

 

Awd

 

FWD is terrible for a drag launch...