|November 18, 2001
First Drive: Audi A4 1.8T with Multitronic
While some may scoff at a front-wheel-drive equipped Audi, claiming it as less significant than its quattro brethren, the new Audi A4 FrontTrak (Audi speak for front-wheel-drive) equipped with Multitronic could be one of the most significant cars to roll out of Ingolstadt in some time.
Why you ask? Besides the fact that this is a totally new A4, the first car to be based on the B6 platform, this front-wheel-drive A4 happens to be fitted with one of the first production chain-driven continuously variable transmissions (a.k.a. CVT) that Audi has dubbed Multitronic.
Multitronic: A New Approach to CVT
While traditional geared transmissions usually have a number of set gear ratios, Audi's new CVT uses a chain drawn between two variators (consider them split pulleys where the two sides can be moved closer together or further apart) to create an infinite number of gear ratios.
CVTs have been traditionally used on smaller engines largely due to limitations of the more common belt driven systems. By using a chain, Audi has achieved application of a CVT for higher torque levels. The Multitronic is rated for 230 lb ft. of torque, making it even useable with the new 3.0-liter V6.
One of the more ingenious facets of Audi's CVT implementation is their choice to include preprogrammed ratios in the Multitronic system. By doing this, they allow for a manual shift experience much like a traditional Tiptronic, though with 6 ratios rather than the 5 ratios found in Tiptronic-equipped models. To the common user, when in manual mode, this is a 6-speed automatic or at least it sure acts like one.
Another key element of the Multitronic system is its use of an electronically controlled multi-plate wet clutch rather than a torque converter. The flexibility of the Multitronic CVT allows Audi to drop the heavier torque converter and thus save considerable weight, yet the clutch still provides the "creep effect" at idle much like an automatic transmission.
A magnesium housing is also used for the Multitronic unit in a further effort to keep weight down. All things considered, Multitronic is a relative featherweight, coming in 33 pounds (15 kilograms) lighter than the equivalent automatic transmission.
The All-New A4
The new A4 is a striking addition to the Audi lineup. Its new design borrows heavily from the revolutionary A6; a calculatedly conservative redesign of a highly successful car positioned in an very competitive market. While the design breaks little new ground, it does make use of some handsome Audi design cues such as the large upper and lower front grills found on the A6 4.2 and the jewel headlights that bear more than a passing resemblance to those on the TT.
The new platform boasts some marked improvements. The frame of the new car is 45% stiffer than its predecessor, while the base suspension is roughly the same as the previous car's Sport Package setup. Rear seat room is also improved; this was perhaps the most apparent shortcoming of the previous car.
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