LSD and Ediff

[spdrcr]

I really can't see why anyone would not want to go for the quaife. I've had one in my Z4 for nearly the last year and it has totally transformed the car. This car only has 170kw (~225hp) but extra balance and grip you get from the diff is amazing.

The diff alone cut nearly a second of my lap times (1:14.0 down to 1:13.1) at a local track that I go to.

The other great thing about the quaife for those that will be using the car as a daily driver is that the diff operates as stock until you need it. No clutch-type lsd that I've experienced does this - you always seem to get some 'chatter' in car parks etc when making tight turns.

I'll wait and test out the e-diff first but if it is not up to scratch then I won't hesitate ordering a quaife atb for my 135i.

[Yearofthe1]

Originally Posted by spdrcr

The other great thing about the quaife for those that will be using the car as a daily driver is that the diff operates as stock until you need it. No clutch-type lsd that I've experienced does this - you always seem to get some 'chatter' in car parks etc when making tight turns.

Is this the only limitation you have encountered with the clutch-type LSD's? The word on the street about Performance Gearing's clutch-type LSD is that it too runs very quietly. Did you alter the gearing ratio for your diff to allow for better acceleration, or is your second better lap time purely attributeable to better transfer of power with the Quaife?

[WAY]

The question for me is, why is the PG one so much more expensive! Quaife will do me just fine I think.

[spdrcr]

Originally Posted by Yearofthe1

Is this the only limitation you have encountered with the clutch-type LSD's? The word on the street about Performance Gearing's clutch-type LSD is that it too runs very quietly. Did you alter the gearing ratio for your diff to allow for better acceleration, or is your second better lap time purely attributeable to better transfer of power with the Quaife?

The only thing I did was change the diff centre, I didn't change the gearing. Same tyres, same brake pads etc etc. I can consistantly turn laps within .2 of a second so the .9 second drop was no coincidence.

[WAY]

Where did you do this and how much does it cost?

[spdrcr]

I got the quaife from Kevin Bird in the UK and had a local BMW specialist (ALS Performance in Sydney) do the install.

[WAY]

Ok. Thinking of doing the same. Bird sells the Quaife ATB for less than $2k to E90 customers, so I wonder if we can get the same deal. Maybe we can get a few Aussies to get this together. I also want to change the gear ratio if I change the LSD though. My car won't be used as a daily driver so I don't really care about fuel efficiency.

[ORIGIN M.]

Wow. I can't see spending 2k for the Quaife. I'll wait until the price drops or something.

[Powerman]

Originally Posted by Powerman

White911, or anyone else, why does LSDs help with braking? I understand the LSD is locked up to bias, and the torque biasing unit only works with torque applied, but how does that help on deceleration? There is no differentiation, and there is no throttle applied. If you are trail braking and turning it is differentiating any way. Understand I know nothing about racing. So why is a LSD better than a Quaife for braking?

Can anyone explain why braking with a speed sensing LSD is better than a torque sensing unit.

[Fast Kiwi]

you know this thread will be completly torn to bits the second we all get a chance to drive the thing right!!?? lol

[Rephlex]

As this is in danger of going round in circles (drifting!) here is a previous thread http://www.1addicts.com/forums/showthread.php?t=3343

and here was my contribution to it;

As mentioned above I’ve had the Quaife ATB differential fitted to my 130i by Kevin Bird Garages in the UK with great success. Birds have worldwide exclusive distribution for Quaife BMW applications including 135i for US.

I’ve emailed Kevin about 135i and supply to North America and had the following response;

“There will be a Quaife solution. We're hoping to get our first car in a couple of weeks to determine which version is required. As indicated on the thread, there is currently no technical information on the construction of the diff outside of the BMW network. So we have to disect one to find out. It's likely to be similar to the late model E93 (335i convertible) model.

“There is practically zero likelihood of there being any interference with the DSC/traction systems. Many existing cars are fitted with this type of system, and no unwanted characteristic or interventions have been produced so far.

“I can't see any reference by BMW calling the 135i system an E-diff. As far as I'm aware, a true E-diff is like that installed on some Ferrari and Porsche cars that uses a servo to modulate the preload on a traditional clutched LSD. The 135 system is much simpler. If a wheel spins, the system applies the brake on the spinning wheel. Main reason why this is wrong, is it generates heat. That heat is taking power from the drive train, and you pay for it in terms of acceleration performance or fuel consumption. In truth, the effect on fuel consumption/acceleration might be too low to notice, but nevertheless, taking energy out of the sytem and throwing it into the air is definitely not an elegant solution (but it is cheap for BMW to install).

“All the BMW cars fitted with this type of system seem to go through rear pads at an alarming rate. Even the M6, with the M-diff doing most of the work, has been seen to kill its rear pads if driven very hard. I know of one M6 owner who claims he had his rear pads changed under warranty at 2,000 miles. He had been hammering the car at a circuit, and was very proud of his achievement!

“On the warranty issue, in the UK it's legally impossible to "void or invalidate warranty". The only way BMW can disclaim liability is if the customer has done something or installed something on the car that has caused a component to fail. They can't easily argue that a major component has failed because of something like a diff. Some Dealers, through ignorance of the facts, claim that warranty can be voided. Get them to put it in writing, and you get a different answer.


"All of the decent diff suppliers out there give warranties that are as good as, or even better than BMW. Quaife give a lifetime warranty on their device, and we add on 3 years labour and consequential damage.”

The 130i diff costs £829 GBP excluding taxes, delivery, duty & installation. Same price for the 335i. That's $1,635 USD today. It's not an exchange basis; I've retained my OEM diff to keep my options open for future cars although I'm unlikely to change any time soon except for a 135i.

The 335i details are all available now through the website www.birdsauto.com and any 135i enquiries can best be answered via the website's enquiry process.

Details of their 335i demo car are available here http://www.birdsauto.com/1-PDFs/E9209920100.pdf

Video of the 335i diff being given a proper workout by Chris Harris of Autocar magazine at a wet Chobham test track HERE :thumbup:

Edit - Letter ref BMW Warranty;





Update: I've just had the following response from Kevin Bird;

We could offer 3 units only at a forum discount of 10%. We've done so many offers on other forums, I don't think we've sold enough at the regular price! Quaife@birdsauto.com is the best email address.

135 isn't proved yet, but would be done as soon as someone decides he needs one. It's the customer demand that causes us to the the test work, at the end of the day.

We are now supplying into the USA, but it's not an exclusive territory for us. However, no-one else is about to order the quantities that Quaife need to make this viable. So essentially, we're the only source presently. Their former USA partner decided to go a different route.

I won't do a pic of the stock at the moment, because it's a bit untidy. However, we have just short of 100 various units in stock and another 30 on order.

Thanks, Kevin.

[Numb3rs]

Originally Posted by #1

Wow. I can't see spending 2k for the Quaife. I'll wait until the price drops or something.

Be aware there is a huge cost of installation because these do not bolt up. BMW has welded the halfshafts, so installation will cost big buck$.

Expect to pay about $1500+ for the install.

[Powerman]

Originally Posted by Numb3rs

Be aware there is a huge cost of installation because these do not bolt up. BMW has welded the halfshafts, so installation will cost big buck$.

Expect to pay about $1500+ for the install.

My understanding was that BMW welded the ring gear to the carrier. I could be wrong.:iono:

Never the less, it is still unclear whether the 1er will require a complete diff swap as the 335is do.

[Tiago]

Originally Posted by Advevo

3.46 is perfect because you can stil hit the limiter. Thats why i choose that.

At what rpm now? On my garage i have the pinion and ring of my E46 M3 because i changed it to 3.91, so will the 3.63 ring and pinion of the M3 fit on the 135i diff?

[natedog_1959]

While you are in there, you might as well install a larger rear sway bar. No sense in having to do that work twice. Nate

[Rephlex]

Originally Posted by natedog_1959

While you are in there, you might as well install a larger rear sway bar. No sense in having to do that work twice. Nate

I believe the E92 M3 bar is compatible and cheap. :thumbup:

[Tiago]

Originally Posted by ehnaych

Top speed in top gear would theoretically be 186.15 mph or 299.58 kph.

I have a program that mix the Cd (0,32), Frontal area (1,86ft^2), RPM, Gears and tire diameter (24,8"). It showed that a 135i need 355hp to reach 186mph at 6800rpm. 306hp = 177mph at 6400rpm. 380hp = 190mph at 6900rpm.
With 3.46 diff you hit the speed limiter at 6350rpm. But if you de-limited the car you will find it to short for a top speed run (175mph at 7100rpm).
So the 3.08diff is the perfect gearing if you have 380hp, which it isn't a difficult number to obtain with this engine. And a shorter gearing it will increase the fuel consumption also, mainly because you will feel it with a lot more torque and therefore you will need to reprise the car all the time. I know it by personal experience from my M3.