[ats86]

So i have been thinking about getting an LSD installed on my 07 335i (pre march 07 production so its just the bolt on) and i was wondering if anyone could offer any insight as to which LSD they found to work the best. I am leaning towards a gear type like the wavetrac... but they are relatively cheap in price compared to say the AA LSD... Do you get what you pay for in this instance? I would love to hear your thoughts.. and advice on the issue of which one to get.. I am open to all suggestions hah

[blisstik]

I've read that Quaife LSD is the way to go. It's really expensive tho. I don't know any alternatives but for the 350Zs that had open differential (base models), they recommend the same brand.

Since its quite a lot of labor, I suggest getting the BEST one.

[ats86]

A dealer down here in SC said it would only be 285 bucks to install. (A pumpkin swap)

[white_hype]

its not the brand of gear thats important its what type it is- viscous is fluid driven so it can overheat and takes a while to engage i would say stay away from viscous- helical and torsen (quaife)work the same and are gear driven and kick in instantly they work great and only have a downfall if one wheel is lifted off the ground. clutch types are strong still work great with one tire in the air, but are noisy and dirty hence you have to change the fluid like every 10k or under

[ats86]

Thanks man.. i was leaning more towards the gear types... havent really checked into clutch types... do they grip better? I have been thinking either the wavetrac or the quaife but havent made up my mind on anything... cannot find alot of into about the wavetrac

[scheherazade]

If your car is before 08', then you don't have the e-diff program.

The E-diff program is active when stability/traction is off. It is designed to act as a simply LSD, which prevents runaway wheel spin.

No e-diff program means that with reaction/stability 100% off, there is no electronic assist to stop a free-spinning wheel.

Quaife only works when wheels have load. If you actually spin a wheel (0 traction on one side), it stops working.

If you had the e-diff software, then the brakes would catch the free spinning wheel, causing a load on that wheel. Which in turn would make the quaife re-engage and you'd be all-good.

This is why I went with Wavetrac... because I don't have the e-diff software (XI) and I want the diff to keep working when one or both wheels slip.




Also, the clutch type LSD's lock depending on two things :
1) acceleraion or decelleration force.
2) wheel spin differential

You'd have to look into each model to see which it is. The common type I've seen is the (1) type.

They are better for super aggressive driving, but they interfere with 'normal' driving. I.E. they partially lock on light acceleration, which causes understeer in turns. Which of course turns to overseer as you apply more power.

For RWD, it's actually 'nice' because it stabilizes your car on soft sweepers.

But for a AWD, it just makes *more* understeer (as they tend to have some to begin with).

-scheherazade

[ats86]

Thanks alot scheherazade, man really appreciate the info!!

[HP Autowerks]

Originally Posted by ats86

A dealer down here in SC said it would only be 285 bucks to install. (A pumpkin swap)

$285 for a Wavetrack install? Sounds like a great deal!

[scheherazade]

I was quoted $350 (+ materials. diff oil, shims, etc) for installation into a spare pumpkin that I have.

$700 total including swapping my existing pumpkin with the rebuilt pumpkin.

-scheherazade

[stressdoc]

Originally Posted by scheherazade

If your car is before 08', then you don't have the e-diff program.

The E-diff program is active when stability/traction is off. It is designed to act as a simply LSD, which prevents runaway wheel spin.

No e-diff program means that with reaction/stability 100% off, there is no electronic assist to stop a free-spinning wheel.

Quaife only works when wheels have load. If you actually spin a wheel (0 traction on one side), it stops working.

If you had the e-diff software, then the brakes would catch the free spinning wheel, causing a load on that wheel. Which in turn would make the quaife re-engage and you'd be all-good.

This is why I went with Wavetrac... because I don't have the e-diff software (XI) and I want the diff to keep working when one or both wheels slip.


-scheherazade

Not exactly. My apologies if what follows seems like a bit of a tirade but there has been a fair amount of misinformation posted regarding "e-diff" and model year differences.

All E9xs have some variant of "e-diff" = traction and stability control via braking and power reduction = DTC/DSC.

"e-diff" is a misnomer. The algorithms for DSC/DTC in later model years are a bit different than earlier models, but nothing very significant.

The effect of DSC/DTC on the actions of the Quaife QDF are complex. The QDF model does not result in completely free spinning of an unweighted wheel as some have suggested. There is always some tension that results in torque transfer.

Put simply, regardless of whether you have a 2007 or a 2009, installing a real LSD (Quaife, wavetrac, whatever) will have a big effect on traction and handling. I attach the Birds blurb. For an unbiased review of the results see
http://www.e90post.com/forums/showthread.php?t=100072

[chiaobaby]

if your making a track car its cool if its an daily driver why not spend it on a intercooler first gives you more horsepower. LSD are nice to have but I would spend it on horsepower first. Good to have if you have the extra $$$ Just my 2 cents.

[dlbrooks18]

Originally Posted by chiaobaby

if your making a track car its cool if its an daily driver why not spend it on a intercooler first gives you more horsepower. LSD are nice to have but I would spend it on horsepower first. Good to have if you have the extra $$$ Just my 2 cents.

what's the use of more horsepower if you can't put all that power down to the ground.. lsd transforms the feel of the car

[stressdoc]

Good prices on the labor if you are getting quality work.

[Adamk24]

I picked up my Quaife LSD from Hp Autowerks for $1400 and it's been everything I wanted it to be. I totally recommend it.

http://www.hpashop.com/product.sc?pr...categoryId=114

[stressdoc]

Quaife or maybe the new Wavetrac seem excellent for most conditions.

[GeorgeSmooth]

Originally Posted by chiaobaby

if your making a track car its cool if its an daily driver why not spend it on a intercooler first gives you more horsepower. LSD are nice to have but I would spend it on horsepower first. Good to have if you have the extra $$$ Just my 2 cents.

I would tend to disagree. I also thought the same but after fitting the LSD I really started enjoying cornering for the first time with this car. Straight line speed you get use too but a corner is always a challenge.


I went with the Quaife as it was the only diff available at the time. Thanks to Harold from HPAutowerks for hooking me up.

[scheherazade]

Originally Posted by stressdoc

All E9xs have some variant of "e-diff" = traction and stability control via braking and power reduction = DTC/DSC.

DSC/DTC is a form of differential lock. I don't think anyone can argue that.

What I've read about is that the algorithms with DSC/DTC set OFF are significantly changed.

Originally Posted by stressdoc

"e-diff" is a misnomer. The algorithms for DSC/DTC in later model years are a bit different than earlier models, but nothing very significant.

With DSC/DTC OFF :
Youtube videos of people '1 wheel burning' on older cars and 'drifting' with newer cars made me believe that the e-diff change is tangible.

Granted, they are just videos... and I wasn't there.

Originally Posted by stressdoc

The QDF model does not result in completely free spinning of an unweighted wheel as some have suggested. There is always some tension that results in torque transfer.

When you corner so hard that the inside wheel lifts off of the ground, the quaife should limp at that stage.

But this is mostly theory... 99.9999% of people here will never experience that scenario...

Generally, I see the wavetrac as a 'theoretically nicer quaife' , since it technically can do something extra in that scenario.

I'll see how mine pans out. Like I said, I'm sure both are adequate in most cases.
I however do want to drift my car now and then, so I wanted something with more aggressive locking, but not as 'intrusive' as a clutch type 1.5 like the os-giken or cusco style LSDs.


I wish there was more technical data about the DSC/DTC OFF modes, and the changes between old and new. I'll grant that I speak about e-diff only from what I've heard or saw on youtube...
(Personally, my XI will free-wheel with DSC/DC OFF. That's all I can verify myself)

-scheherazade

[stressdoc]

Bottom line: "e-diff" brakes the wheel with less traction. This has been part of the DTC/DSC system for a long time. The current algorithm does not allow for complete freedom of the DTC system. Hold that button down for as long as you like and you are never completely free (shades of Lexus big brother legal section). The older system allowed complete disabling, so yes, in some conditions you can get more one-wheel spin with the old model. But BMW "e-diff" does not involve any changes to the differential. It never changed. The only changes made were in the software controlling the braking in the DTC system. But "e-brake" wasn't a very catchy label to sell sporty BMWs.

BMW "E-diff" is deceptive lingo, plain and simple. Some marketing peanut in AG no doubt read about the real e-diffs in Ferrari and Porsche and figured they could dupe most of the buyers most of the time. Starting with a crew of 135 fanboys that thought they really had something over the 335s.

Funny how such a wonderful thing has not found its way into the M3 -- thank God!