wavetrac lsd

[titium]

About to pull the trigger on a wavetrac for my 135i. from what i can tell reviews look good.

anything i should be aware of before I do?

anyone have one and care to comment?

[jvb6806]

Are you planning on installing yourself? From what I understand the shims are snap rings of different sizes and the kit is $$$. I went the diffsonline route earlier this year and couldn't be happier. I also replaced all of the hardware because they have a gnarled flange and BMW suggests replacement. Reuse the mount bolts for the carrier and the rear case, but I replaced all of the drive shaft and axle bolts. I bought all of them from TMS when I ordered some other stuff but DOL also has them.

I was however convinced to go with the 30/90 clutch type and I do not regret it. It is cheaper than the helical diffs and if you ask any autoxer with it they love it.

[titium]

what's it like as a daily driver?

[jvb6806]

It drives totally fine. I don't notice anything in normal driving, but when I autoX the difference is incredible. I was concerned about daily driving the car too but a few people pointed out that a TON of cars have a clutch LSD from the factory and they are just fine. I don't know why I was concerned about it.

If you do go the clutch type route make sure you change the oil after break in. I waited the full 1,200 miles and the oil was BLACK. I don't really DD the car anymore, but I am going to change the gear oil at the start of every season regardless of mileage.

Again, I don't know if you are building it yourself, but the DOL came with new stub shafts, seals, and ready to go in. I reused the OE cover, but there are a few options out there if you want a fancy finned one.

[spxxx]

Clutch or helical style?

[jvb6806]

Originally Posted by spxxx

Clutch or helical style?

He is talking about the wavtrac which is helical... I was convinced to go clutch type and do not regret it.

[spxxx]

Originally Posted by jvb6806

He is talking about the wavtrac which is helical... I was convinced to go clutch type and do not regret it.

That's right, I was thinking Quaife who I believe offers both.. I assume you get in a decent amount of track time. I'm pretty happy with my helical but then again I've never pushed my buddies 1M to the limit to feel a clutch type LSD activate.

[jvb6806]

I try to be at the track 2-3 weekends a month. The 30/90 ramp locks very quickly and is awesome for autoX.

[Kgolf31]

Originally Posted by spxxx

That's right, I was thinking Quaife who I believe offers both.. I assume you get in a decent amount of track time. I'm pretty happy with my helical but then again I've never pushed my buddies 1M to the limit to feel a clutch type LSD activate.

Well that's because it's not actually a Clutch LSD

(Unless he's running something different than Non-OEM)

[spxxx]

Originally Posted by Kgolf31

Well that's because it's not actually a Clutch LSD

(Unless he's running something different than Non-OEM)

Isn't it just hydraulic? I could just Google but doesn't the hydraulic system determine clutch pressure? I haven't researched in a while

[Suprgnat]

Originally Posted by spxxx

Isn't it just hydraulic? I could just Google but doesn't the hydraulic system determine clutch pressure? I haven't researched in a while

The hydraulic system is "reactive", that is to say there must be slip first for it to respond. Clutch type limited slips are "anticipatory" and lock on the application of torque, before any slip occurs.

[rac]

Originally Posted by titium

About to pull the trigger on a wavetrac for my 135i. from what i can tell reviews look good.

anything i should be aware of before I do?

anyone have one and care to comment?

i'd research your clutch type options as well. i'm helical and they are ok, but in hindsight i wish i spent more time looking into clutch options as an alternative. more flexibility to set up for track manners imo. if your not that track orientated then probably doesn't matter.

[titium]

Originally Posted by rac

i'd research your clutch type options as well. i'm helical and they are ok, but in hindsight i wish i spent more time looking into clutch options as an alternative. more flexibility to set up for track manners imo. if your not that track orientated then probably doesn't matter.

which helical did you go?

[rac]

Originally Posted by titium

which helical did you go?

mfactory. in terms of general characteristics i doubt the wavetrack / quaife / mfactory would be much different. although i could be wrong.

its on my mind that i could probably push / under-steer less under power if i had the flexibility of trial and error with different clutch type set-ups or had a quality recommendation from someone like diffsonline. if your based in the US probably worth calling dan and discussing your application with him, he seems very busy and knowledgeable.

[MFactory]

Originally Posted by jvb6806

It drives totally fine. I don't notice anything in normal driving, but when I autoX the difference is incredible. I was concerned about daily driving the car too but a few people pointed out that a TON of cars have a clutch LSD from the factory and they are just fine. I don't know why I was concerned about it.

That's because you have an oem/oem-based Plate LSD, which are nowhere near the effectiveness/performance of a real aftermarket Plate LSD with full adjustability.

The oem Plate LSD's are designed to be used on a street car, thus compromised in terms of performance (even when they are "modified" by DiffsOnline/VAC etc). Even a Helical LSD will outperform the oem Plate LSD's on both street and track (except in certain circumstances such as free-wheeling). There is a reason why Helical LSD's sell so well for the M cars (which all have the oem LSD as standard).

Yes, the oem/oem-style Plate LSD's may be slightly cheaper (depending on who you purchased it from), but for only a few hundred dollars more than a Helical LSD setup, you can have a much better performing setup with an aftermarket Plate LSD (for a track car)

The reason why the oem/oem-style Plate LSD's have taken off in North America (and only here) is because 1) huge profit margins, 2) very tame for a street car, 3) Limited availability of aftermarket Plate LSD's in North America (only EU/Asian companies make them)

[MFactory]

Originally Posted by spxxx

That's right, I was thinking Quaife who I believe offers both.. I assume you get in a decent amount of track time. I'm pretty happy with my helical but then again I've never pushed my buddies 1M to the limit to feel a clutch type LSD activate.

Quaife (the brand) only offer a Helical LSD.

However, Quaife (the company) bought-out and now own Tran-X, which are Plate LSD's, but they are only available for old school European cars (classic UK motorsports)

[Taskmaster]

Save for lockup under deceleration, I don't see how a clutch type is superior to a Wavetrac (specifically) diff.

[MFactory]

Originally Posted by TheAxiom

Save for lockup under deceleration, I don't see how a clutch type is superior to a Wavetrac (specifically) diff.

The Wavetrac is a torque biasing differential; it does not lock, and can only transfer upto 66% torque to the wheel with traction.

In comparison, a Plate LSD does lock (that's how it functions) and, depending on the brand of LSD, can provide upto 100% lock capacity, multiple engagement angles (i.e you can set how aggressive you want it to lock) and multiple pre-load settings (i.e you can set how aggressive you want it to be during slow cornering)

On the track (circuit/auto-x/rally), there is a night & day difference between a Helical/Torque Biasing differential (which is non-adjustable), and a fully adjustable Plate LSD. If you are an inexperienced track driver and do not know how to adjust a Plate LSD to your driving/track preference, then you would find a Helical/Torque Biasing differential easier to get the hang of.

On a street car, then generally a Helical/Torque Biasing differential is the better choice.

[titium]

Originally Posted by MFactory

The Wavetrac is a torque biasing differential; it does not lock, and can only transfer upto 66% torque to the wheel with traction.

In comparison, a Plate LSD does lock (that's how it functions) and, depending on the brand of LSD, can provide upto 100% lock capacity, multiple engagement angles (i.e you can set how aggressive you want it to lock) and multiple pre-load settings (i.e you can set how aggressive you want it to be during slow cornering)

On the track, there is a night & day difference between a Helical/Torque Biasing differential (which is non-adjustable), and a fully adjustable Plate LSD

On a street car, then generally a Helical/Torque Biasing differential is the better choice.

do torsen diffs have the same torque bias under deceleration?

[MFactory]

On deceleration (i.e no load), a Helical/Torque Biasing differential does not function. This is why some people get a Helical/Torque Biasing differential confused with a 1.0way Plate LSD, thinking they are the same thing (when they are not)

They are good for new/inexperienced track drivers, but if an advanced driver wants to push his car to the limit, it is advantageous to switch to a more advanced Plate LSD

[titium]

Originally Posted by MFactory

On deceleration (i.e no load), a Helical/Torque Biasing differential does not function. This is why some people get a Helical/Torque Biasing differential confused with a 1.0way Plate LSD, thinking they are the same thing (when they are not)

They are good for new/inexperienced track drivers, but if an advanced driver wants to push his car to the limit, it is advantageous to switch to a more advanced Plate LSD

what are pros and cons of a helical vs a 1 way plate lsd?

[MFactory]

Pro's for Helical:
- Cheaper
- Maintenance Free
- NVH Free

Con's for Helical:
- Limited in torque transfer to traction wheel (% dependant on brand of LSD)
- Stops functioning when free-wheeling (although Wavetrac does have their wavelock feature to kind of overcome this)
- Non-Adjustable to your driving style i.e one-size-fits-all

Pro's for Plate:
- Fully adjustable to your driving style (dependant on brand of LSD) i.e Lock Capacity, Engagement/Aggressiveness, Pre-load

Con's for Plate:
- More expensive
- Takes trial & error (and experience) to setup LSD correctly i.e NOT one-size-fits-all. This is why I am hugely against all these oem/oem-based setups being sold by the "other" BMW specialists. If you have to rely on a "specialist" for advice and to setup your LSD for you, then a Plate LSD is not for you. The whole point of a Plate LSD is for its adjustability. If you are not going to touch it, then buy a Helical LSD
- Increased NVH. Unless you don't mind sounding like a tractor in the parking lot, and constant jerking at low corner speeds, these are not for you. Not so bad with an oem/oem-based Plate LSD, but then again, those aren't exactly performance LSD's, no matter what the "specialist" tries to tell (sell) you