Mk2 Resto Project- Some Slip, No Slide

As we continue our restoration and upgrades to the project mk2 (or as we call it in the office: the neverending story, ed), the number of period-correct mods that are available to us keeps getting smaller. But after a summer of spirited driving, we found something to add to the list.

Despite being great in terms of packaging and cost-savings, front-wheel-drive cars are not without their drawbacks. There’s the weight bias to the front, torque steer, and—the big one—traction issues. As the front tires are expected to handle both lateral grip issues with steering and acceleration, mid-corner wheelspin is almost always guaranteed. Even worse, if the FWD car in question is putting down a lot of power, wheelspin during acceleration becomes another issue.

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Now with the mk2 and it’s eight-valves-of-fury, excessive power isn’t exactly a big problem. But mid-corner, the inside tire still tends to want to break loose just when the driving starts to get fun. So a limited-slip differential became the first big upgrade the car actually needed.

The only question was which one to choose. The latest whiz-bang electronically-controlled Torsen differentials—like the one found in the mk7 Performance Pack-equipped cars—would be sweet, but impossible to buy, let alone retrofit into a car with no wheel-speed sensors. We’ve used gear-type LSDs before in previous project cars (Quaife was so common a word thrown around the mk4 forums back in the day, its name almost lost its giggle-worthiness), so we knew what we would be getting if we went down that route. But when chatting with long-time Vortex sponsor Autotech last summer, we were presented with a new option.

 

 

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The Wavetrac gear differential, unlike the conventional models, promises to keep load on the inside wheel, even if it’s unloaded. Gear-type differentials need load on both axles in order to function, but if we hit the curbing (as we were taught to do at our Audi sportscar experience courses) or even in very hard cornering, the inside wheel doesn’t get any drive. The result is that there can be only intermittent power delivered to the gripping (outside) wheel. The cam device inside the Wavetrac generates a load (to replace the lost torque as the axle unloads) that’s then biased to the gripping wheel, which ultimately makes the power delivery more consistent.

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After a ton of explanations, charts, and graphs that were, frankly, over our heads (dammit, we’re web geeks, not engineers), we said “sounds great” and decided to see for ourselves. As we already had to address a small leak on our 020 transmission, once it was pulled, we sent it and our newly-acquired LSD & ARP bolt kit to a local transmission shop for installation. The very next day, we shoehorned the trans back into the mk2 engine bay.

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Because the Wavetrac is a 1-way, we didn’t get any coupling when lifting off the throttle and braking into a turn, so our initial test drives of the mk2 around town didn’t feel any different. When pushed, however, through the rare twisty Illinois roads, the extra grip was noticeable. Again, with about 130hp (optimistically) estimated, wheel spin wasn’t a huge issue with the mk2. But on those rare occasions where we did encounter a loss of grip, it really killed our momentum as we’d drive towards the next corner.

Where we really found the greatest gains in traction was at H2oi in October. Not so much on the long drives from Chicago to Ocean City and back, as there’s a reason Indiana, Ohio, and Western PA are considered “flyover” states, but thanks to Hurricane Joaquin, we dealt with wet weather conditions for almost a full week. Knowing full well we wouldn’t win any drag races, occasionally passing far more powerful cars on the outside of a turn made us feel like experts in the little hatchback.

In the coming season, we’ll be taking the mighty mk2 to a handful of track events, where we’ll be able to eke out that last few tenths with our new Wavetrac differential. But for now, we’re already convinced it’s worth it—even if it costs more than we paid for the car.