I was planning on purchasing a LSD in the near future for my 95 Del Sol Vtec, and was wondering what the differnce between a 1.5 and a 2 way LSD? My car will be mainly used in AutoX and HPDE's with very little drag racing thrown in there for fun. Can anyone show me some insight into what the differnces are... Thanks

 

Clutch-type limited slip differentials


A clutch-type LSD uses a set of clutch discs, that are connected to each wheel, and the discs are clamped together at a certain pressure when in operation. When one wheel tries to rotate faster than the other wheel, the clutch discs start to slip, the faster disc transfers power to the slower disc through friction, hence transferring power from the faster wheel to the slower wheel.



A clutch-type LSD responds immediately to any slippage, unlike the viscous-type LSD, and is so better from a performance standpoint. A clutch-type LSD is also much more easily upgradeable to handle high horsepower, as the number of clutch discs can be easily increased or the clutch disc sizes can be enlarged. Most aftermarket clutch-type LSDs have larger/more clutch discs. The downside with a clutch-type LSD is that with the slipping of the clutch discs, they eventually wear down and will require maintenance. Also clutch discs will chatter when they are engaged, so a clutch-type LSD is not as quiet as other LSDs.



Clutch-type LSDs are often offered as 1-way, 2-way or 1.5-way. A 1-way LSD only engages the clutch discs only on acceleration, while a 2-way LSD engages the clutch discs on both acceleration and deceleration. If the clutch discs work to limit slip on deceleration, they can optimize traction under braking, but at the same time as they transfer power from the faster wheel to the slower wheel, this increases oversteer in turns. Therefore a 2-way LSD is generally considered more difficult to handle, but superior for handling, while a 1-way LSD is more forgiviing. A 1.5-way LSD is a compromise between a 1-way and 2-way, as it engages the clutch discs with less pressure on deceleration, which allows for more slip on deceleration and hence less oversteer.



Note: a viscous LSD is always 2-way by design.

 

here is the other type of LSD


Viscous-type limited slip differentials


A viscous-type LSD uses a thick fluid sandwiched between plates, one plate being connected to (drives) each wheel. When a rotation difference occurs between wheels, the faster plate spins the fluid which in turn spins the slower plate, hence transferring power from the faster wheel to the slower wheel.


A viscous-type LSD has the advantage of requiring little to no maintenance, since the fluid never wears out. However, from a performance standpoint, a viscous-type LSD is not ideal. On a viscous LSD, it takes a split-second for the LSD to react to slip as the fluid must speed up before it starts turning the slower plate. On higher horsepower cars, any lag in response resulting in uneven traction is especially undesirable.



A viscous-type LSD is often used as the center differential on AWD cars, where the delay in the transfer of power (from front to back) is not as critical. It is also often used in OEM applications where cost, ease of maintenance and quiet operation is important.

 

so whats a helical lsd? some form of viscous style? good info by the way

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kanzenr91si &raquo;</TD></TR><TR><TD CLASS="quote">so whats a helical lsd? some form of viscous style? good info by the way</TD></TR></TABLE>

AFAIK a helical LSD (like a Y1 JDM oem LSD) uses gears not totaly sure how it works but it defo had gears in there

BillB

 

Helical gear type torque biasing LSD

This LSD uses the nature of worm/helical gears to transfer torque in
one direction and not in the other. This includes all the Honda and
Quaife LSD's. These LSD's are sufficient for light duty racing and are
known to have a tendency to break, due to the nature of the design.
This usually occurs when one wheel is unloaded (like in the air) and
then loaded very suddenly.

Ratchet type LSD's

These are the most extreme of the LSD. These come on and off, with no
in between settings. These include the detroit locker types which are
used in RWD race cars (NASCAR) and the AP-Lockheed Suretrac ($2000+)
used on FIA homologated Touring cars.

 

'Ratchet' types aren't technically a limited slip.

They are a locking differential. Limited slips have a biasing ratio, and can not achieve full lockup. Say they have a ratio of 4:1, they can put 80% torque at one side. Trying to put more than that will still result in one wheel slipping.

OEM stuff usually has a lower ratio, to feel less aggressive, aftermarket can put more.

The big market for lockers is off-road vehicles, where you need 100% lockup. In a situation where you are traveling less than 1mph and climbing a 4ft rock with just one tire while the other is in the air, a limited slip still functions as if its an open diff.

Lockers basically function like a spool whenever you are on the power. There are drop in types for most truck axles, starting at about $200.

Of course, we often just broke out the TIG and welded the spider gears in our beater Jeeps.. my last CJ-5 had F/R detroits, though..