Lsd

[IWantACelica]

What is it. I jsut got into cars a couple of days ago so im still tryin to learn all of this stuff.

[Fools716]

Limited Slip Differential...and a powerful drug.

[Deaks2]

Tada!

http://auto.howstuffworks.com/differential.htm

[CreepingJeff]

limited slip differential. from what i understand... when one wheel slips, the LSD allows more torque to be applied to the wheel that is not slipping. it's basically a way for you to get extra traction when you experience wheel spin.

[IWantACelica]

thanks for the info. Does this come stock ona celica and if it doesnt can you get it somehow? Is it a good mod?

[RiCelicaBoi]

no, it does not come stock, they run about $700-$800.

[gachamann]

From what I've read here, it doesn't do much good as far as off-the-line traction (for dragging and such). I was thinking about it for the turbo upgrade, but if that's true it would be kinda pointless.

It reportedly makes a noticeable difference in autocross, though.

[LaZyCeLiCa916]

LSD = Limited Slip Differential...For GT-S the best LSD there is for it is PHANTOM GRIP LSD. LSD creates more tracktion and your car would be pulling with 2 wheel. LSD makes 2 wheels accelerate at the same time...instead of a one...which helps you launch. When people burn out...its only one wheel really burning out...but with lsd its 2.

[Deaks2]

The Phantom Grip is the cheapest LSD, not the best.

It is a clutch-based device, a hellical 1.5 or 2-way LSD would be far superior thanks to its ability to work in both acceleration and deceleration. Clutch-based LSDs act as a locking differential, and as such are ONLY good for the drag strip.

[Oo DaRk StAr oO]

Helical LSD's are awesome.

I have a Visious is my Rex. Its okae, alittle to slow for me.

[nyoneway]

Originally posted by Deaks2
Clutch-based LSDs act as a locking differential, and as such are ONLY good for the drag strip.

Do you know what you are talking about? Clutch LSD is better than any other type LSD in a road course/track.

Here's a read on the Kaaz LSD (Clutch) vs Torsen Gear (Helical)

"Here's why Torsen LSD's suck. For you road racer types, as soon as you get one wheel off the ground the Torsen becomes an open differential, in order for it to work both wheels must have complete contact with the ground. When your hanging 1.1g corners and a wheel lifts under power you instantly have no power. That sucks real bad. The KAAZ clutch type LSD is not like that. The KAAZ LSD will remain engaged when a wheel lift under cornering.

Rally drivers and road race types alike prefer these Clutch type LSD's because they are more predictable, they will always do the same thing over and over again. Repeatability is very important if you want to achieve consistency. Manufacturers, and race teams alike (Mazdaspeed, Nismo, etc) use the clutch type design. It is the one that works. When people say words like Mazdaspeed, RE Amemiya and Nismo you should all bow in reverence, the rest of the world does.

Another problem associated with Torsen type differentials is that by design they try and force the internal gears against the housing in order to achieve the breaking force which will lock the LSD. The same features that make the Torsen quiet make it weak. When a Torsen breaks, it breaks its own housing and sends expensive little bits everywhere, usually breaking the transmission/rear end gear/housings with it. We do not like weakness, refer to second paragraph regarding handing in your testicles.

Now for you Drag racer types, this is where you want the direct engagement of a clutch type differential like a KAAZ. The KAAZ 1.5 way and 2 way diffs, have a cam lock type of engagement. When power is applied, it immediately engages the clutch packs, which in turn locks the wheels. What does this mean to you? Reaction time, lips, that's what. It reacts right away, and it has direct engagement. Important when trying to rip off good good times. The Torsen type must have slippage in order for it to engage both wheels, this costs you time.

KAAZ LSD's can be rebuilt whereas Torsen types require little if no servicing. True but lets look into this further shall we? Usually a clutch type LSD will not require servicing until about 100,000 miles into its life, and the parts are all available separately. We say, so what? I can have a better LSD, which in ten years I may have to service, or I can have the chance of having my tranny reduced to a pile of rubble. In ten years I won't own this pile of scrap, I may be dead, or I'll be driving a porsche, better yet, I'll be chauffeured around town in my limousine surrounded by my harem of Truly 18 poster girls.

Now that you have the facts you can be the judge, oh by the way KAAZ LSD's are usually half the price of a Torsen type. That should seal the deal right there."

[Deaks2]

Yes, and that is why soooo many cars with LSDs and AWD use clutch-based devices... :rolleyes:

Torsen is not hellical by the way, it is a worm drive. Hellical LSD's are made by Quaiffe, etc...

[erok]

nyoneway - good points on the clutch type LSD. Where do you get your info on the clutch type longevity though? I've talked with a couple autocrossers who've worn out clutch type LSDs in only a couple years. One owner of a highly modded 2nd gen RX7 would break them so frequently that he just gave up and went back to running with an open diff.

Undoubtedly, clutch type LSDs are better for race cars with super stiff suspensions and limited wheel travel, but for intermediate use, like in a street driven autocross car, the geared LSDs have the advantage of long life (barring an unlikely catastrophic failure) and unobtrusive operation. Also, while clutch LSDs may operate more efficiently, I've never seen a street driven front drive car lift a front wheel in a turn on a track or autocross, so I don't see how the gear type LSD gives up much by remaining open when one wheel has no traction at all. At the end of the day, I think a gear type is more practical for a street driven car. The difference in price would be more than made up for the first time the clutch LSD needed service. There is a reason why every factory performance car I can think of that has a LSD uses either helical, viscous or torsen LSDs and not clutch types. Not to mention the reasons why most race cars DO use clutch types. As you said, it's not because the gear type is cheaper. In my experience, truly competative race cars don't make good street cars and vice versa. Just something to think about, since this is the noob forum after all.

Also, I don't mean to rule out clutch type LSDs for street use, I am sure all the consumer clutch type LSDs available can be adjusted to work well on the street with the minimum maintenence possible. It'd be great to hear from some of the people on the boards who actually have clutch LSDs in their cars.

Edit: I just checked your sig and assume it's TRD's clutch LSD in your car. So what do you think of it? Anything you don't like? Have you ever driven a car with a gear type to compare with? Just curious.

[nyoneway]

I don't mean clutch type LSD have longer life, I meant they generally can handle more power reliablity.

It's like comparing a domestic V8 to a Honda I-4. Sure the honda last longer, but the V8 handles more power reliably. Get it?

Yes clutch LSD wears out, and can be rebuild, but when a helical or torsen LSD fails, it usually takes your whole tranny alone with it because it shatters and the metal shards mess up the rest of your tranny.

[Deaks2]

Torsen LSD's are enclosed in a seperate transfer case a la Audi Quattro, and therefore a failure would be containted to said casing and would not affect the transmission.

Hellical LSD's by Quaiffe and IPT have LIFETIME warranties, Quaiffe even stating that they will honour the warranty on their parts in race conditions. I have only ever seen one Quaiffe LSD fail (1.5 way unit on an ITR) and it was because of improper tranmission maintenance.

"Here's why Torsen LSD's suck. For you road racer types, as soon as you get one wheel off the ground the Torsen becomes an open differential, in order for it to work both wheels must have complete contact with the ground. When your hanging 1.1g corners and a wheel lifts under power you instantly have no power. That sucks real bad. The KAAZ clutch type LSD is not like that. The KAAZ LSD will remain engaged when a wheel lift under cornering.


This statement makes no sense. If a Torsen diff. were to have a have a wheel off the ground the other would continue to receive power, otherwise under a wheelslip condition it would also transform into an open diff. Do not believe all the marketing speil from Kaatz.

As for your comment regarding clutch-based LSD's in rally cars and race cars, Subaru WRC uses a viscious coupling, Audi uses a Torsen worm-device, GM uses a hellical model in the C5-R, Mitsubishi uses an electronically controlled hellical in the WRC Lancer, Ferrari and almost all other F1 teams use 2-way hellical LSDs.

[nyoneway]

Torsen LSD's are enclosed in a seperate transfer case a la Audi Quattro, and therefore a failure would be containted to said casing and would not affect the transmission.

Audi's LSD is OEM. Do you have an Audi? I don't and my LSD is in my tranny, then what is your point?

Hellical LSD's by Quaiffe and IPT have LIFETIME warranties, Quaiffe even stating that they will honour the warranty on their parts in race conditions. I have only ever seen one Quaiffe LSD fail (1.5 way unit on an ITR) and it was because of improper tranmission maintenance.

Quaife LSD's are overbuilt because of that, that means its HEAVY, much heavier than a clutch type LSD to compensate for their weakness in their design. Now if your Quaife LSD do fail, they do not pay for the tranny you just blew nor the labor you have to paid to get it replaced.

This statement makes no sense. If a Torsen diff. were to have a have a wheel off the ground the other would continue to receive power, otherwise under a wheelslip condition it would also transform into an open diff. Do not believe all the marketing speil from Kaatz.

It's no marketing scam, do a search on yahoo read about the performance differences between a torsen/helical LSD and clutch type and everyone will point out that fact that most professional or competitive racers use clutch type because its more predictable when a wheel is lifted off the ground.

As for your comment regarding clutch-based LSD's in rally cars and race cars, Subaru WRC uses a viscious coupling. Audi uses a Torsen worm-device

Subaru WRC uses viscous in their center differential, most 4wd cars uses viscous LSD in their center differential (one notable exception is Audi Quattro).

GM uses a hellical model in the C5-R, Mitsubishi uses an electronically controlled hellical in the WRC Lancer, Ferrari and almost all other F1 teams use 2-way hellical LSDs.

The Lancer EVO have 2 different computer controlled differential system. Their ACD, Active Center Differential, is a computer controlled clutch pack LSD, their AYC, Active Yaw Control, uses gear type differential.

Most of these 4wd systems that comes stock from the factory (like STI WRX, Lanver Evo, Audi Quattro), the type of the LSD is not relevant because its designed work as a 4wd system that uses different type of LSD and electronic control to distribute torque to 4 wheels.

Most modern F1 cars do NOT use torsen/helical LSD, you are reading too much into Quaife's "marketing spell", instead they use computer hydrolic controled clutch pack differentials.

Anyways, lets forget about all these different LSD system and focus on the main point of this discussion and that is a FWD car like the Celica with no active differential systems in place, a regular clutch pack LSD will outperform a typical torsen/helical.

[Deaks2]

Originally posted by nyoneway
Anyways, lets forget about all these different LSD system and focus on the main point of this discussion and that is a FWD car like the Celica with no active differential systems in place, a regular clutch pack LSD will outperform a typical torsen/helical.

I agree to disagree. :p