Why you need a LSD if you like cornering!

[puma]

and what kind of lsd has been proven to be good for this platform?

[gramicci101]

Originally Posted by CSG Mike

The car comes with a Torsen, but if you lose traction with one of the wheels, then the differential effectively becomes open. Loss of traction can be lifting a wheel, or spinning a wheel. In this case, the inner wheel is spinning.

Doesn't that defeat the purpose of having a limited slip differential? I recognize that it's not a locker, but suddenly having an open diff when one wheel loses traction makes it seem like the limited slip is REALLY limited.

[7thgear]

Originally Posted by gramicci101

Doesn't that defeat the purpose of having a limited slip differential? I recognize that it's not a locker, but suddenly having an open diff when one wheel loses traction makes it seem like the limited slip is REALLY limited.

please note this is for when one wheel loses complete traction (or on very different traction surfaces)

[CSG Mike]

Originally Posted by gramicci101

Doesn't that defeat the purpose of having a limited slip differential? I recognize that it's not a locker, but suddenly having an open diff when one wheel loses traction makes it seem like the limited slip is REALLY limited.

A locker is something used on a truck or tow vehicle to force it into locked or unlocked state. A LSD is reactive, and dynamic.

Yes, that's the downfall of a Torsen, but the Torsen type LSD has the least maintenance (change fluid) and makes zero noise no matter the situation.

Originally Posted by puma

and what kind of lsd has been proven to be good for this platform?

Any clutch type. OS Giken and Cusco are the two we've tested, and both work well, and can be set up to be very daily driver friendly. The Cusco is cheaper up front, but the OSG has a longer service interval for major services.

Originally Posted by stugray

So did you pull the fuse so that the VSC would not respond?



Ummm... SO slowing the spinning wheel would slow you down??
I thought that was the whole concept of a LSD.

The purpose is to prevent the slip to begin with. We use the Pedal Dance.

[ZDan]

Originally Posted by CSG Mike

The car comes with a Torsen, but if you lose traction with one of the wheels, then the differential effectively becomes open. Loss of traction can be lifting a wheel, or spinning a wheel. In this case, the inner wheel is spinning.

I've never gotten inside wheelspin in either the S2k (T2) or the FD (T2R). Any time I've gotten wheelspin at the track, it's been both rears.

Both wheels on the ground, you shouldn't be getting inside wheelspin with a torsen diff. If the inside rear is lifting while on the gas, setup may be off. I haven't tracked an FR-S, so maybe its 55/45 weight distribution is more of a problem here on grippy tires...

In my experience, the Torsens in my cars act similarly to the lightly-preloaded clutch/ramp-type in my 240Z. Actually, the FD's T2R acts more like the Z's clutch-type all around than the T2 in the S2k.

Yeah, you can crank in a ton of preload and make a clutch-type act practically locked (very high effective bias ratio), but that sucks for handling (unless you just like understeer). With a torsen you're limited to about 2.5-4 bias ratio, but usually that's enough. At least with a well-balanced car...
Then again they didn't put a Torsen in the Boss 302 LS (which has similar weight distribution issues as the FR-S/BRZ and a ton more hp) because it was *worse* than the clutch-type that went in lesser Boss 302s...

Personally, I'm happy either way. Never felt the need for a Torsen or Quaife gear-type LSD in the Z while others were happily spending $$$$ for them, and don't feel a need for a clutch-type in the S2k or FD. If it works, it works. And if it doesn't work for one driver/car at the track, it doesn't necessarily mean it won't work for another car/driver at the same level.

My opinions based on my experiences with other cars, so take it fer what it's worth

[diss7]

Mechanical diffs are quite brutal in a daily.

I have one. I run it because it's so much better for drifting. But it does take away alot of street comfort.

[CSG Mike]

Originally Posted by ZDan

I've never gotten inside wheelspin in either the S2k (T2) or the FD (T2R). Any time I've gotten wheelspin at the track, it's been both rears.

Both wheels on the ground, you shouldn't be getting inside wheelspin with a torsen diff. If the inside rear is lifting while on the gas, setup may be off. I haven't tracked an FR-S, so maybe its 55/45 weight distribution is more of a problem here on grippy tires...

In my experience, the Torsens in my cars act similarly to the lightly-preloaded clutch/ramp-type in my 240Z. Actually, the FD's T2R acts more like the Z's clutch-type all around than the T2 in the S2k.

Yeah, you can crank in a ton of preload and make a clutch-type act practically locked (very high effective bias ratio), but that sucks for handling (unless you just like understeer). With a torsen you're limited to about 2.5-4 bias ratio, but usually that's enough. At least with a well-balanced car...
Then again they didn't put a Torsen in the Boss 302 LS (which has similar weight distribution issues as the FR-S/BRZ and a ton more hp) because it was *worse* than the clutch-type that went in lesser Boss 302s...

Personally, I'm happy either way. Never felt the need for a Torsen or Quaife gear-type LSD in the Z while others were happily spending $$$$ for them, and don't feel a need for a clutch-type in the S2k or FD. If it works, it works. And if it doesn't work for one driver/car at the track, it doesn't necessarily mean it won't work for another car/driver at the same level.

My opinions based on my experiences with other cars, so take it fer what it's worth

Datalogging would say otherwise on my S2k... I have the benefit of having DBW/VSA, and individual wheel speed sensors.

If you're at the limit of adhesion of the rear tires under cornering and accelerating, you'll get single tire wheelspin before both tires spin, because the torque going to the inner and outer wheels are not the same. If you launch the car, then yes, you'll spin both wheels because they're getting relatively even loading, but under cornering, that just isn't the case.

[CSG Mike]

Originally Posted by diss7

Mechanical diffs are quite brutal in a daily.

I have one. I run it because it's so much better for drifting. But it does take away alot of street comfort.

Do you have someone locally that can reconfigure it for you? I may be able to give you some guidance.

What brand do you have, and what is your current configuration?

[diss7]

Originally Posted by CSG Mike

Do you have someone locally that can reconfigure it for you? I may be able to give you some guidance.

What brand do you have, and what is your current configuration?

Don't get me wrong, I'm happy with it.

I'm just stating that the axle binding and tyre chirping that comes with these diffs is something most aren't aware about.

I have a TRD 2way.

[CSG Mike]

Originally Posted by diss7

Don't get me wrong, I'm happy with it.

I'm just stating that the axle binding and tyre chirping that comes with these diffs is something most aren't aware about.

I have a TRD 2way.

Those two things can be completely eliminated for street driving with proper configuration, which is the downside most people are afraid of.

The problem is, most retailers just sell LSDs, but don't have a clue about how to actually configure/customize them.

[diss7]

Originally Posted by CSG Mike

Those two things can be completely eliminated for street driving with proper configuration, which is the downside most people are afraid of.

The problem is, most retailers just sell LSDs, but don't have a clue about how to actually configure/customize them.

Some of your posts can come across a bit arrogant FYI. (I'm one to talk)

It depends how tight you set it. I wanted mine super tight, because its for drifting.

There is always going to be binding and tyre squeal in a daily with a mechanical. It just depends on how tight the diff is set, as to how often it happens.

Having it so lose that it NEVER happens in a street car, would mean its too loose IMO.

[ZDan]

Originally Posted by CSG Mike

Datalogging would say otherwise on my S2k... I have the benefit of having DBW/VSA, and individual wheel speed sensors.

Your S2k is different from mine.

If you're at the limit of adhesion of the rear tires under cornering and accelerating, you'll get single tire wheelspin before both tires spin, because the torque going to the inner and outer wheels are not the same.

With an open diff, torque going to the inner and outer wheels is *always* the same. The reason you get inside wheelspin is not because more torque is going to the inside wheel, it's because the inside wheel has less grip because it is unloaded.

With either a clutch-type or a Torsen, frictional forces transmit torque that's trying to spin the inside wheel up over to the loaded wheel side.

If setup is such that the rear becomes totally or nearly totally unloaded, then a highly-preloaded clutch type will have the advantage of continuing to drive the outside rear wheel when the torsen will spin the inside.

If you launch the car, then yes, you'll spin both wheels because they're getting relatively even loading, but under cornering, that just isn't the case.

It just *is* the case for my S2k and FD. At the track (not a drag strip), I always spin both rears at the same time, never get inside wheelspin.

PLENTY of Torsen equipped cars have no problem putting pretty big power down at the track on DOT R tires.

If your setup is such that you are lifting the inside rear a lot, yeah, you'll benefit from a highly-preloaded clutch-type diff.

Lots of Z guys ran rear roll stiffness biased setups that required a superstiff diff, but I went with softer rear roll stiffness (no rear bar) and a very lightly loaded diff. Both methods work, but I liked the way mine handled better...

[CSG Mike]

Originally Posted by diss7

Some of your posts can come across a bit arrogant FYI. (I'm one to talk)

It depends how tight you set it. I wanted mine super tight, because its for drifting.

There is always going to be binding and tyre squeal in a daily with a mechanical. It just depends on how tight the diff is set, as to how often it happens.

Having it so lose that it NEVER happens in a street car, would mean its too loose IMO.

Would you be able to achieve exactly what you want with a lower initial torque setting (dd friendly) with a higher rate of lockup (aggressive engagement)? What is the benefit of making your 2 way so tight that it is basically always locked? You might as well use a welded diff if you've eliminated the "differential" part of "LSD" by effectively permanently locking the diff.

IMO, the purpose of a LSD is to be able to have the wheels locked only when you need/want it to be. My interpretation of what you wanted would be that you want them locked permanently.

[diss7]

Originally Posted by CSG Mike

Would you be able to achieve exactly what you want with a lower initial torque setting (dd friendly) with a higher rate of lockup (aggressive engagement)? What is the benefit of making your 2 way so tight that it is basically always locked? You might as well use a welded diff if you've eliminated the "differential" part of "LSD" by effectively permanently locking the diff.

IMO, the purpose of a LSD is to be able to have the wheels locked only when you need/want it to be. My interpretation of what you wanted would be that you want them locked permanently.

Quite simple really, you need it that tight for drifting in the wet, when you're giving it very little beans before wanting both wheels to engage. Having it that tight on decel means it feint drifts like a boss.

If I'm super smooth and slow during a slow maneuver than I can stop it engaging, but its so slow often I don't bother and just let if bounce/bind.

Also remember that no matter how tight the diff is, you can always use it like an open diff by pressing the clutch in. I'll often do that say if I need to make a u-turn, I just get enough momentum to do it without power.

Every drift car and most of my rwd street cars ive run Nisbro diffs. (NZ Slang for a welded diff) They're good because they always work, unlike a torsen. (My torsen was already getting lazy after 2 drift days) But the 2 way gives me the compromise I wanted, basically all the good things of a locker, but with some small areas where it performs like an open.

I don't disagree that I run it tighter than what would be ideal for circuit. I wouldn't even run a 2 way for a circuit car. I'd be much more inclined to run such a loose decel setting that I might as well run a 1 way. But my point from my previous post still stands, that if its so loose that it NEVER binds/engages on the street, then its probably too loose.