164 limited slip differential now (155, Spider, GTV, Lancia Thema)

["." <maxid@xxxxxxxxxxxxxx>]

I am looking for other alfisti who are interested in getting together an order for limited slip differentials for the 164. The differential in a car allows the outside wheel in a turn to rotate faster than the inside wheel. Unfortunately, the "open" type of differential used in most cars, including the 164, has undesirable effects in situations of unequal traction, because power is directed toward the wheel with lesser traction. A wheel that has lost grip will be allowed to speed up while the one that has grip will be slowed down and lose power, resulting of loss of propulsion. The problem is especially obvious during accelleration. In a front wheel drive vehicle it is worse when going uphill.

This is where the limited slip differential (LSD) comes in. An LSD improves traction in conditions of snow, ice, or rain. In racing, it improves lap times by reducing inside-wheel spin during acceleration out of a turn. A traditional LSD is based on friction discs that respond to differences in drive axle speed. This type has been in offered for decades as OEM epuipment on select rear wheel drive vehicles. This includes not only sporting marques such as Alfa Romeo but also cars that arguably have more emphasis on all-weather prowess, such as Volvo 240. However, the friction-based type of LSD is poorly suited for FWD use on a street car because its inherent tendency to equalize drive axle speeds influences negatively on steering. Another shortcoming is that the friction material will eventually wear out and need replacement.

The 1980's saw the emergence of a new type of LSD based on a clever combination of helical gears. It is difficult to explain in writing how it works, but it has the desirable effect that torque is directed to the wheel with the most traction. This type is often referred to as Torsen (for TORque SENsing), a well-known brand found as OEM fitment on many cars and trucks. A helical gear, torque-sensing type LSD is compatible with FWD because it responds to differences in torque rather than axle speeds. It is also a remedy for torque steer. Japanese car makers were the first to use this type of LSDs on powerful FWD cars, but Ford Europe also puts a Quaife-manufactured one in its Focus RS. Because this type of LSD does not incorporate friction plates, it does not require maintenance or special lubricants. 

Alfa Romeo never offered any type of LSD for the 164. Two Italian companies offer friction-based LSDs for the 164, but they are priced beyond what most consumers would want to pay (2,500 euros) and require periodical rebuild. Quaife is a UK-based manufacturer that has previously made a batch of LSDs for the 164. The Quaife differential is described at www.quaife.co.uk. Several sources indicate that the differential will also fit some Alfa Romeo 155, FWD Spider, FWD GTV, as well as Lancia Thema. It will not fit Saab 9000, Alfa 156 or any RWD Alfa. I will be happy to assist in finding information about a specific application.

Quaife's US distributor, Autotech Quaife America, has offered to make arrangements for another batch if we can fill 10 orders at $1,246 each. The price will drop to just below $1,000 if we can get 30 or more orders. Quaife America requires a 50% deposit ($623 each). 

Delivery is approximately 3 months from the time the order is placed with Quaife America. The price does not include shipping within the United States. The Quaife differential comes as a unit that replaces the stock differential. Labor involved in installation is comparable to a clutch replacement and it may be favorable to combine the two jobs. Quaife America offers a limited lifetime warranty which applies even if it is used in racing (described at www.quaifeamerica.com).

Alfa Romeo Owners Club USA has generously offered to collect the deposits but has no other involvement in the venture. Also, I do not receive any benefit except that I need for others to place orders before Quaife will make a batch. You can place your order with AROC Administrator Shayna Geller at 877-399-2762 (9-5 EST). The offer is open to all US and non-US residents, but US residents must be AROC members ($60). The deadline is September 15, 2003.

I will answer questions at 
410-358-1884 (EST)
or maxid
@
mindspring.com
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