Track Car Help

[Kaido_RR]

Hey,

Just after some opinions on fellow members who race/track there skylines. Its time for a new lsd and i'm not really sure which one to pick 1.5 or 2way. The car is use for track work, atm i currently active in drifting but would like to move onto grip events later down the track.

[evil_weevil]

I had a 2nd hand nismo 1 way and that was fine for me.

hardcore would be 2 way!

Have you driven any others with a 1 way, 1.5 way or 2 way to get a feel for them?

[BOZ22N]

Yer what he said ^^^^^^^^^^^^^^^^

A 1 or 1.5 way would be the shit for street and track, tight 2 ways on the street are funny but ok as well.

[Neil]

Please excuse my lack of understanding,,, but can someone explain the differences in 1,,,1.5 and a 2 way Nismo diff.

I bought a Nismo diff a long long time ago and can't remember which it was. It's now fitted (what a pain on a garage floor) just needs oil and an exhaust gasket.

Our old single spinner was a 4.11 (37:9) and the newey is 4.08 (49:12).

Neil.

[BOZ22N]

Here you go old mate, i stole the info from wiki as i have been drinking some what.

BTW where you been hiding?

Broadly speaking, there are three input torque states: load, no load, and over run. During load conditions, as previously stated, the coupling is proportional to the input torque. With no load, the coupling is reduced to the static coupling. The behaviour on over run (particularly sudden throttle release) determines whether the LSD is 1 way, 1.5 way, or 2 way.

If there is no additional coupling on over run, the LSD is 1 way. This is a safer LSD: as soon as the driver lifts the throttle, the LSD unlocks and behaves somewhat like a conventional open differential. This is also the best for FWD cars, as it allows the car to turn in on throttle release, instead of ploughing forward.

If the LSD increases coupling in the same way regardless of whether the input torque is forward or reverse, it is a 2 way differential. Some drifters prefer this type as the LSD behaves the same regardless of their erratic throttle input, and lets them keep the wheels spinning all the way through a corner. An inexperienced driver can easily spin the car when using a 2 way LSD if they lift the throttle suddenly, expecting the car to settle like a conventional open differential.

If the LSD behaves somewhere in between these two extremes, it is a 1.5 way differential, which is a compromise between sportiness and safety.

Physical differences

The spider gears mount on the pinion cross shaft which rests in angled cutouts forming cammed ramps. The cammed ramps are not necessarily symmetrical. If the ramps are symmetrical, the LSD is 2 way. If they are saw toothed (i.e. one side of the ramp is vertical), the LSD is 1 way. If both sides are sloped, but are asymmetric, the LSD is 1.5 way.

As the input torque of the driveshaft tries to turn the differential center, internal pressure rings (adjoining the clutch stack) are forced sideways by the pinion cross shaft trying to climb the ramp, which compresses the clutch stack. The more the clutch stack is compressed, the more coupled the wheels are. The mating of the vertical ramp (80°-85° in practice to avoid chipping) surfaces in a 1 way LSD on over run produces no cam effect and no corresponding clutch stack compression.

Hope that helped.

[Neil]

Bloody hell thats confusing...

Ryan,,,what if I told you I spotted no clutch pack,,,wiki may get very confused.

BTW where you been hiding?,,,Hiding,,,I wish,,,Club Pres is a very behind the scenes and up front job,,,after SnS I'm stuffed.

See you at Texi tiger.

Neil.

[Kaido_RR]

Neil from my limited understanding

1way only works during acceleration, where a 2 way works under both acceleration and braking (which i say work i mean lock)

1.5way is inbetween it locks under acceleration and braking however it is not has aggressive as the 2way (jack of all trades)

2way are the weapon of choice for drifters.

I'm still tossing up between he 1.5 or 2way and the GT LSD PRO or PRO TT (both nismo diffs)

[bigmikespec]

Here you go old mate, i stole the info from wiki as i have been drinking some what.

BTW where you been hiding?

Broadly speaking, there are three input torque states: load, no load, and over run. During load conditions, as previously stated, the coupling is proportional to the input torque. With no load, the coupling is reduced to the static coupling. The behaviour on over run (particularly sudden throttle release) determines whether the LSD is 1 way, 1.5 way, or 2 way.

If there is no additional coupling on over run, the LSD is 1 way. This is a safer LSD: as soon as the driver lifts the throttle, the LSD unlocks and behaves somewhat like a conventional open differential. This is also the best for FWD cars, as it allows the car to turn in on throttle release, instead of ploughing forward.

If the LSD increases coupling in the same way regardless of whether the input torque is forward or reverse, it is a 2 way differential. Some drifters prefer this type as the LSD behaves the same regardless of their erratic throttle input, and lets them keep the wheels spinning all the way through a corner. An inexperienced driver can easily spin the car when using a 2 way LSD if they lift the throttle suddenly, expecting the car to settle like a conventional open differential.

If the LSD behaves somewhere in between these two extremes, it is a 1.5 way differential, which is a compromise between sportiness and safety.

Physical differences

The spider gears mount on the pinion cross shaft which rests in angled cutouts forming cammed ramps. The cammed ramps are not necessarily symmetrical. If the ramps are symmetrical, the LSD is 2 way. If they are saw toothed (i.e. one side of the ramp is vertical), the LSD is 1 way. If both sides are sloped, but are asymmetric, the LSD is 1.5 way.

As the input torque of the driveshaft tries to turn the differential center, internal pressure rings (adjoining the clutch stack) are forced sideways by the pinion cross shaft trying to climb the ramp, which compresses the clutch stack. The more the clutch stack is compressed, the more coupled the wheels are. The mating of the vertical ramp (80°-85° in practice to avoid chipping) surfaces in a 1 way LSD on over run produces no cam effect and no corresponding clutch stack compression.

Hope that helped.

That is a great explanation!

What about a torsion diff. like that offered by Quaife for FWD cars and front diffs. for 4WD cars? Is there a significant advantage of a torsion diff. over a 1.0 way for the front differential on a GTR?

[NickR33]

I had a Cusco 2 way in my street/track car and it was fine... you have to be a real muppet to spin the car on deceleration... you really should be braking in a straight line anyway but its not going to kill you if you carry a little brake into the corner... they are not quite as scary as people would have you believe but do take a little getting used to