[GreekboyD]

The VAC differential cover works for any of them. Wavetrac, Quaife, or OSG.

[335dFan]

Originally Posted by GreekboyD

The VAC differential cover works for any of them. Wavetrac, Quaife, or OSG.

I guess I meant is it really needed for the Quaife rather than will it fit?

[GreekboyD]

Do you plan to track the car? If so, then I'd say yes.

[335dFan]

Originally Posted by GreekboyD

Do you plan to track the car? If so, then I'd say yes.

Some of the more clever forum members would say "if you are spending so much money on your suspension, why are you not tracking it?". Which would be a good question of course even though I want it to handle equally well on the street. But the simple answer is most likely I would not do much more than a couple of HPDEs a year. Unless of course I catch the track fever. But the old reflexes are not what they used to be, and am not Paul Newman, so my estimate is priobably realistic. Who knows. $800 is a lot of money for a diff cover.

[taibanl]

Originally Posted by 335dFan

Some of the more clever forum members would say "if you are spending so much money on your suspension, why are you not tracking it?". Which would be a good question of course even though I want it to handle equally well on the street. But the simple answer is most likely I would not do much more than a couple of HPDEs a year. Unless of course I catch the track fever. But the old reflexes are not what they used to be, and am not Paul Newman, so my estimate is priobably realistic. Who knows. $800 is a lot of money for a diff cover.

+1. Why would it be needed?

[GreekboyD]

Originally Posted by taibanl

+1. Why would it be needed?

Check out the link in post #43.

[gruppeM3]

Originally Posted by GreekboyD

Check out the link in post #43.

Man that is one nice diff cover. Looks like a quality piece too

[fl335i]

I love my VAC cover. And I had VAC send a drain plug to Gold Plug and they put a huge monster GOLD magnet on it. I love driveline bling. The factory cover has no drain. Really, no drain? PITA for oil changes... and the VAC cover has more capacity, cooling fins and is billet aluminum for heat transfer. Plus it looks awsome from behind. To other gear heads.

[GreekboyD]

Originally Posted by fl335i

I love my VAC cover. And I had VAC send a drain plug to Gold Plug and they put a huge monster GOLD magnet on it. I love driveline bling. The factory cover has no drain. Really, no drain? PITA for oil changes... and the VAC cover has more capacity, cooling fins and is billet aluminum for heat transfer. Plus it looks awsome from behind. To other gear heads.

Sounds sick. Does the VAC cover have a drain plug that you had altered into a magnetic one?

[FormerRotor]

Originally Posted by fl335i

I love my VAC cover. And I had VAC send a drain plug to Gold Plug and they put a huge monster GOLD magnet on it. I love driveline bling. The factory cover has no drain. Really, no drain? PITA for oil changes... and the VAC cover has more capacity, cooling fins and is billet aluminum for heat transfer. Plus it looks awsome from behind. To other gear heads.

I'm jealous

[tigermack]

I have to say, I'd not go for a Quaife if I do plan to track my car. I have an OSG in my e36 and my bro has an OSG in his MS3, they are superior than the Quaife type LSD I had in my MZ3.

[GreekboyD]

Originally Posted by tigermack

I have to say, I'd not go for a Quaife if I do plan to track my car. I have an OSG in my e36 and my bro has an OSG in his MS3, they are superior than the Quaife type LSD I had in my MZ3.

Super lock or TCD?

[Techevo]

Originally Posted by Killerfish2012

To answer your second question, No, I don't think that the OS giken is better than the other two to justify the price.

It depends what you’re doing with the car. If it’s hardcore trackwork the OS Giken is far superior due to the high percentage lock-up available (ie better traction) and adjustability to let you change maximum lock-up and pre-load.
If it’s mainly a road car, a pure helical is fit and forget, quiet and maintenance free.

Originally Posted by Killerfish2012

Besides the fact that you have to use special diff fluid from os giken ($50/liter)

Um, not really, all plated LSD’s required an oil which has a friction modifier added to it for smooth lock-up of the friction plates and discs, you do not need to use the oil from OS Giken. Most major oil manufacturers sell ‘LS’ oil, such as Millers LS CRX, Castrol B373, Redline Shockproof etc. If the diff is too noisy, try adding some friction modifier to quieten or reduce chatter.

Originally Posted by Killerfish2012

its a one way differential like the quaife. The wavetrac diff is the only 2 way diff (works under zero load). Meaning when you let off the throttle, the quaife, and os giken behave like an open diff

A Quaife isn’t a 1 way, 1.5 way or 2 way diff. This classification isn’t used for a non locking torsen (TORque SENsing) helical diff. The Quaife still transfers torque under deceleration.

The OS Superlock will be available in 1, 1.5 or 2 way. 1.5 way is exactly what you want for a RWD track/race car. This means it has maximum lock-up on acceleration (% lock-up depending on plate config, ramp angle and oil used) and a smaller percentage lock-up on deceleration (off throttle and braking) This slight lock-up on decel helps keep the rear end stable. It is not ‘open’ when you let off the throttle!

A 2 way diff isn’t called as such because it works under zero load (nothing to do with it) it is because it has the same percentage lock-up under acceleration and deceleration, and only really to be fitted to a ‘drift’ car due to the oversteer characteristics it causes.

Originally Posted by Killerfish2012

Also the quaife and OS giken can only transfer power to the non slipping wheel if there is at least some traction in the slipping wheel. If there is no traction at all, such as in ice, or if that wheel is lifted off the ground, they will both behave like open diffs

True for the Quaife, but completely wrong for the OS. One major benefit of a plated LSD such as the OS, is it’s ability to lock-up regardless of grip, no grip, one wheel off the ground etc. This why race cars use them, due to their stiff suspension and anti-roll bars causing low droop and a tendancy to lift wheels over kerbs etc.

Originally Posted by Killerfish2012

Functionally speaking, wavetrac is by far superior to the rest.

Functionally, the full plated OS diff is the most efficient differential due to being able to create the highest percentage lock-up of all types.

Basically these are some guidelines for using the different diffs.

For a mainly road car, with occasional trackwork where the suspension droop is adequate to not cause a lifted wheel, the Quaife diff is preferable.

If there is any possibility of lifting a wheel a Wavetrac is preferential.

For maximum traction and lock-up and much better adjustability, but will require more maintenance and not fit and forget, the full plated diff such as the OS, is preferable.

[GreekboyD]

Good post Techevo.

[FormerRotor]

^+1

[taibanl]

+2 thanks

[Killerfish2012]

Originally Posted by taibanl

+2 thanks

taibanl = taliban?

[tigermack]

Originally Posted by GreekboyD

Super lock or TCD?

Super lock.

[GreekboyD]

Sweet. I'm leaning towards the Super Lock too.

[taibanl]

Originally Posted by Techevo

I



A Quaife isn’t a 1 way, 1.5 way or 2 way diff. This classification isn’t used for a non locking torsen (TORque SENsing) helical diff. The Quaife still transfers torque under deceleration.



True for the Quaife, but completely wrong for the OS. One major benefit of a plated LSD such as the OS, is it’s ability to lock-up regardless of grip, no grip, one wheel off the ground etc. This why race cars use them, due to their stiff suspension and anti-roll bars causing low droop and a tendancy to lift wheels over kerbs etc.



F

For a mainly road car, with occasional trackwork where the suspension droop is adequate to not cause a lifted wheel, the Quaife diff is preferable.

If there is any possibility of lifting a wheel a Wavetrac is preferential.

For maximum traction and lock-up and much better adjustability, but will require more maintenance and not fit and forget, the full plated diff such as the OS, is preferable.

Right now I have stock suspension so obviously I have enough flex that both wheels stay on the ground. Anyone know how stiff the BMW performance suspension is? Will I be ok with a Quaife? Is Maintenance the only downside to Wavetrac over Quaife?

[335dFan]

Originally Posted by taibanl

Right now I have stock suspension so obviously I have enough flex that both wheels stay on the ground. Anyone know how stiff the BMW performance suspension is? Will I be ok with a Quaife? Is Maintenance the only downside to Wavetrac over Quaife?

As a point of reference, VAC Motorsports is putting a Quaife on mine, and my suspension is going to be modded as follows: M3 Rear Subframe Bushings, all the M3 Suspension Components Kit from GetBMWParts.com (front and rear arms, both sways), AC Schnitzer Springs, and JRZ RS1 dampers. I mention this because VAC is still suggesting Quaife is best for me. Granted I will only track a couple of times a year at HPDE.

[GreekboyD]

Don't forget to upgrade your differential bushings as well. Makes sense to do it when your differential is getting done.