[Marcus-SanDiego]

Before I get started, let me get some of the formalities out of the way. I have a 2009 335 6MT. I had a welded factory differential. As a result, I had to purchase a full, complete final drive from HP Autowerks.

Harold was a total joy to work with. I ordered the Quaife on July 8. I was told that it could take as long as seven days for HP Autowerks to ship the diff to me. In fact, the diff shipped out on July 14, six days after I placed my order. I received the diff a day later.

I got the LSD installed yesterday. The install took one hour and 40 minutes. Euro Auto Spot did the work. Shane Nguyen, owner of Euro Auto Spot, and Steve, new master tech that was recently hired by Euro Auto Spot (he was most recently at BMW South County), tagged teamed the install.

I watched the install and took pictures along the way. I was surprised how much work was involved in the install -- despite the fact that I bought the complete final drive (pumpkin with Quaife inside).

I drove straight home after the install but one thing was obvious from the start. The car, when you accelerate, feels more sure now. It's very obvious. I didn't have a chance to hit any fun on- or off-ramps, but I'm looking forward to it. It's too bad the LSD isn't a factory option -- or standard equipment -- on the 335. This car could have really benefited from it. Oh, well. I have one now. I already think the money was well spent but I am sure that I'll really think that once I toss the car around a little bit.

By the way, I retained the stock gearing ratio (3.08).

In the meantime, here are a bunch of miscellaneous pictures. I think I took some 40 pictures or so. I'll supplement this thread as I find time to upload the pictures.


Removing the exhaust



After everything was loosened up -- dropping the diff



Diff being lowered



Diff being lowered



Half shafts without diff installed



Diff cover cleaned and then prepared so that it can be attached to new diff unit



Tightening stuff up after diff was reinstalled



New torx screws being added to half shaft














As I get more pictures, I will supplement this thread.

[fruition3000]

Congrats!!! u r a brave soul. I would feel nervous about my car being torn apart.
Let me know when ur done tossing the car around.

[The HACK]

I drove straight home after the install but one thing was obvious from the start. The car, when you accelerate, feels more sure now. It's very obvious.

That doesn't sound right, unless the new LSD has a different ratio. Limited Slip basically acts when it senses different rate of slip on one side or another. So if you're going mostly straight and wasn't pushing, you most likely will never feel the benefit of an LSD. It doesn't have any affect on drivability if you're not slipping on one side.

[Marcus-SanDiego]

Originally Posted by The HACK

That doesn't sound right, unless the new LSD has a different ratio. Limited Slip basically acts when it senses different rate of slip on one side or another. So if you're going mostly straight and wasn't pushing, you most likely will never feel the benefit of an LSD. It doesn't have any affect on drivability if you're not slipping on one side.

I was pushing. And I was actually changing lanes at the same time. Maybe it just helps the car not break loose. Not exactly sure how to describe it.

[Belarus]

& Congrats !

[The HACK]

Originally Posted by Marcus-SanDiego

I was pushing. And I was actually changing lanes at the same time. Maybe it just helps the car not break loose. Not exactly sure how to describe it.

Pushing how? Engaging traction control? Having significant wheel slip?

Not doubting your claims, but it runs counter to logic and experience. Unless the Quaife unit is similar to the M differential, which I don't think it is, it is incapable of doing what you described. Typical torsen based or any sort of automatic biasing differential only "locks" or attempts to lock the diff when it senses a large amount of speed differential between the drive wheels. On lane change maneuvers where no actual SLIP is detected between the wheels the LSD will act as an "open" diff. Unless I am mistaken these diffs are not like BMW M diffs where a combination viscous pressure pump and a clutch pack is deployed to allow power to be sent to the OUTSIDE wheel even when there's no slip.

Where a Quaife or Torsen style diff is mostly felt is when TURNING at high grip level deficiency. I.e. slow corners where power needs to be applied at high rate, thus on an open diff it'll send power to the inside wheel, where a torque biasing diff or torsen diff will actually allow the diffs to lock up and send some power to the outside vs. an open diff sending all power to the inside. I've driven my share of open diff equipped cars, torsen style diffs, ///M clutch based diffs driven by pressure pumps, and to be honest, where it's apparent between the different style diffs is actually mostly on the track. For street purposes, even when pushing, they hardly ever come in play. And where they're most obvious is the rate of rotation of the vehicle, not how "planted" it feels. That's more a function of suspension/damper/spring rates.

But I'm blabbering. Never had a Quaife style LSD so I can't really say if it's not dissimilar to the ///M diff where it's clutch-packs driven by pressure pumps (from what little research I did it does not appear so). It's just hard for me to imagine where anyone would feel significant difference outside of a track environment on an open diff vs. LSD.

Carry on.

[Marcus-SanDiego]

Originally Posted by The HACK

Pushing how? Engaging traction control? Having significant wheel slip?

Not doubting your claims, but it runs counter to logic and experience. Unless the Quaife unit is similar to the M differential, which I don't think it is, it is incapable of doing what you described. Typical torsen based or any sort of automatic biasing differential only "locks" or attempts to lock the diff when it senses a large amount of speed differential between the drive wheels. On lane change maneuvers where no actual SLIP is detected between the wheels the LSD will act as an "open" diff. Unless I am mistaken these diffs are not like BMW M diffs where a combination viscous pressure pump and a clutch pack is deployed to allow power to be sent to the OUTSIDE wheel even when there's no slip.

Where a Quaife or Torsen style diff is mostly felt is when TURNING at high grip level deficiency. I.e. slow corners where power needs to be applied at high rate, thus on an open diff it'll send power to the inside wheel, where a torque biasing diff or torsen diff will actually allow the diffs to lock up and send some power to the outside vs. an open diff sending all power to the inside. I've driven my share of open diff equipped cars, torsen style diffs, ///M clutch based diffs driven by pressure pumps, and to be honest, where it's apparent between the different style diffs is actually mostly on the track. For street purposes, even when pushing, they hardly ever come in play. And where they're most obvious is the rate of rotation of the vehicle, not how "planted" it feels. That's more a function of suspension/damper/spring rates.

But I'm blabbering. Never had a Quaife style LSD so I can't really say if it's not dissimilar to the ///M diff where it's clutch-packs driven by pressure pumps (from what little research I did it does not appear so). It's just hard for me to imagine where anyone would feel significant difference outside of a track environment on an open diff vs. LSD.

Carry on.

Hack, regardless of the blabbering, I appreciate the comment. I've never had an LSD before. I'm gonna track this car around sweeping turns.

[persian54]

Congrats!

This was the next mod on my list... but.. yeah u know

[P4335i]

Thanks Marcus for the update. I've had work done at Euro Auto Spot also and it's comforting to know they can do LSD's once I'm ready to go that route.

[wazup773]

Lucky you I wish I had money for LSD

[boom]

I can support the OP's claims of a more planted feeling. I got dinan installed yesterday and it definitely feels more surefooted on my daily commute. Hard to explain fully but it just feels more solid and predictable.

[boom]

I can support the OP's claims of a more planted feeling. I got the dinan LSD installed yesterday and it definitely feels more surefooted on my daily commute. Hard to explain fully but it just feels more solid and predictable.

[cstavaru]

Originally Posted by The HACK

But I'm blabbering. Never had a Quaife style LSD so I can't really say if it's not dissimilar to the ///M diff where it's clutch-packs driven by pressure pumps (from what little research I did it does not appear so).

You haven't driven a car with a LSD and jump to all kinds of conclusions...at least you admit you're blabbering

[Gesler]

He meant a "Quaife style LSD". And his post is definitely one of the more informative ones I have read on this forum.

Originally Posted by cstavaru

You haven't driven a car with a LSD and jump to all kinds of conclusions...at least you admit you're blabbering

[rbaldwin28]

I think what he is referring to is the one wheel spin that some of the tuned cars get even in a straight line when rolling at 25-30 mph and going WOT. I have a quaife also and it does feel very different when accelerating from low speeds in a straight line. With an open diff once you get one wheel to slip all power takes the path of least resistance and spins the slipping wheel even more. Now it doesn't so the car feels more planted.

[rbaldwin28]

Originally Posted by The HACK

But I'm blabbering. Never had a Quaife style LSD so I can't really say if it's not dissimilar to the ///M diff where it's clutch-packs driven by pressure pumps (from what little research I did it does not appear so). It's just hard for me to imagine where anyone would feel significant difference outside of a track environment on an open diff vs. LSD.

Carry on.

Hard to imagine feeling a difference off the track? So you have never had a car with LSD then? You really think we would spend thousands of dollars if it made no difference off the track? Trust me it makes a difference every time I drive my car, period.
Edit. ts that you have not driven a tuned 335 with LSD and open Diff.

[GaryS]

Originally Posted by boom

I can support the OP's claims of a more planted feeling. I got the dinan LSD installed yesterday and it definitely feels more surefooted on my daily commute. Hard to explain fully but it just feels more solid and predictable.

I can't really describe it either, but I can feel it almost all the time. It feels like the rear wheels are gripping the road between them, and they grip harder when I accelerate or turn, which feels extremely confident. Of course they're not gripping the road between them, but that's the best I can do to describe the feeling.

[GQMONEYGRIP]

I am really loving my quaife lsd on my 2007 e92 6mt stripper with only sport package and SSTT. I can really feel the difference even going in a straight line or just regular city driving. It has really transformed the car and you do not need to be on always on the track or drifting the car to notice and appreciate the difference the quaife makes. I get a mild thunk from the rear only if i am stopped and really slam it into first gear from neutral- not if it is done slowly - so far I hear this is "normal" for the unit and related to slack in the system and is intensified by the more robust differential.

A bit off topic but to the guys running a quaife and still on the OEM Bridgetone runflats what tire pressures are you running? I thought running 3-5 lbs higher in the rear is good with the LSD. I need rear tires soon (i have 16000 miles) and will have to decide if i stay with the runflats or switch all 4 tires to nonrunflats but so far they have been ok for me.

[juice13]

Originally Posted by Marcus-SanDiego

Hack, regardless of the blabbering, I appreciate the comment. I've never had an LSD before. I'm gonna track this car around sweeping turns.

All I want to know is if the "traction controlled engagement" light on the dash blinks less often now that you have an LSD installed. In other words, does the differential control wheelspin (through whatever torque bias control it is designed to use) before the DCT does (by applying brake to spinning wheel)?

Just be careful when you fully disengage the electronic traction control. I can image your car will behave quite differently now that both rear wheels loose traction, not just one.

[scottp999]

Originally Posted by juice13

All I want to know is if the "traction controlled engagement" light on the dash blinks less often now that you have an LSD installed. In other words, does the differential control wheelspin (through whatever torque bias control it is designed to use) before the DCT does (by applying brake to spinning wheel)?

Just be careful when you fully disengage the electronic traction control. I can image your car will behave quite differently now that both rear wheels loose traction, not just one.

Much less often. I don't see it unless I am getting sideways in 1st gear (DTC). I can feel both wheel's pushing now under hard straight line acceleration, when I used to have DTC cutting in and applying the rear brake. My rear brakes will last much longer.

To the OP - great pictures. Do you have one with them using the tool on the driveshaft nut?

This is the best modicfication after say tune and methanol. Should come from the factory with an LSD option.

Harold at HP Autowerks is top notch! One of the best vendors for the BMW community.

[3002 tii]

Originally Posted by rbaldwin28

Hard to imagine feeling a difference off the track? So you have never had a car with LSD then? You really think we would spend thousands of dollars if it made no difference off the track? Trust me it makes a difference every time I drive my car, period.

You do realize Hack drives a Z4M which is equipped with a diff so to answer your question, yes he has driven a car with a LSD.

OP - glad you like your Quaife LSD. I've been researching my options for a while and upto last week I was leaning towards a clutch style but I may go the same route as you, Quaife with stock gearing (pretty content with the 3.46 ratio and I'll save $$$). Lifetime warranty, great reputation, lack of maintenance requirement are all big pluses.

[rbaldwin28]

Originally Posted by Dubbedown

You do realize Hack drives a Z4M which is equipped with a diff so to answer your question, yes he has driven a car with a LSD.

OP - glad you like your Quaife LSD. I've been researching my options for a while and upto last week I was leaning towards a clutch style but I may go the same route as you, Quaife with stock gearing (pretty content with the 3.46 ratio and I'll save $$$). Lifetime warranty, great reputation, lack of maintenance requirement are all big pluses.

Honda civic has a diff too. That"s a clutch type LSD if I am not mistaken, not a gear type Automatic Torque Biasing LSD such as the one being discussed here. I have owned both and I can't believe anyone who has owned a car with LSD would say that they don't notice off the track between open diff and LSD. Or maybe he hasn't driven a car with 300 ft/lbs of torque and an open diff. We would know if you were not talking for him.