VAG four-wheel drive systems and brand names

[Dutch4x4]

"What four-wheel drive system is used in my Octavia 4x4 and how does it compare to Audi's quattro system?"

Since the launch of the original Audi quattro (also known as "Urquattro"), the Volkswagen-Audi Group have developed, tested and deployed various four-wheel drive systems for their cars.

For years, the systems and the brand names were interchangeable. This changed when VAG introduced the Swedish Haldex clutch as a part-time 4WD solution for their smaller cars with transversely mounted engines. From that moment on, "quattro" was no longer a system but a brand name for Audi 4WD cars. Conversely, "4motion" was introduced as a brand name for VW's 4WD cars. Depending on engine lay-out, "quattro" and "4motion" can now point to both Quattro IV and Haldex systems.

Here's a rundown of VAG's 4WD systems and brand names used over the years. This is followed by a brief explanation of the various types of differentials used by 4WD car manufacturers.

Brand names

Audi: quattro

VW: syncro, followed by 4motion

Seat: 4

Skoda: 4x4

Systems

Quattro I: open front diff, open center diff (manual lock), open rear diff (manual lock). No ABS when locked.

Full-time manually engaged four-wheel drive.

Was on: original Audi quattro (also named "Urquattro"), Audi 80/100 quattro.

Syncro: open front diff, viscous coupling acting as the center diff, open rear diff.

Part-time automatically engaging four-wheel drive.

Was originally developed by Audi, but sourced to VW as "syncro". Similar line of thought to the Haldex system, with the VC engaging rear drive when needed. Crude system with serious drawbacks, such as a lack of ABS integration, which needed the 4WD system to be switched off under braking, using a secondary clutch. Volvo also went on to use it on their earlier Cross-Country models, adding a TC system at the front and an LSD at the back - complicated and flawed. Also on 911 Carrera 4, but then that's originally a RWD car...

Quattro II: open front diff, torque sensing ("torsen") center diff, open rear diff (manually lockable for "those" situations in the rough). No ABS when rear is locked, auto de-lock when speed exceeds 15mph.

Full-time automatically engaged four-wheel drive.

Was on: the Audi quattro ('88-'91, still nicknamed "Urquattro"), Audi 80/90 quattro, Audi 100/200 quattro, Audi Coup

[will_]

There is also a lot of good information on Wikipedia, although I think the post above is probably clearer because of the excellent section explaining clutch and differential systems.

[Wardy]

Brill post - good work. Very informative

And answered a few questions I didn't even know I wanted answering

Steve

[will_]

Ever wondered how a Torsen differential works? Read this white paper and you'll wish you never asked!