[G.I.Joe]

I never did thank you, Former_Boosted_IS, for this excellent review/DIY guide. It helped me a lot in deciding to go with the Quaife LSD.

My only trouble was getting the money together.... Well that's sorted now!

I will have my Quaife ATB LSD installed tomorrow by a professional mechanic, not that I have 10 thumbs or anything, but he has a proper lift and tools, and he has rebuild several diffs before.

[Former_Boosted_IS]

Originally Posted by G.I.Joe

I never did thank you, Former_Boosted_IS, for this excellent review/DIY guide. It helped me a lot in deciding to go with the Quaife LSD.

My only trouble was getting the money together.... Well that's sorted now!

I will have my Quaife ATB LSD installed tomorrow by a professional mechanic, not that I have 10 thumbs or anything, but he has a proper lift and tools, and he has rebuild several diffs before.

G.I.Joe, I am glad the review was helpful. It is not a cheap mod, but it offers a lot of fun to driving the car. To be honest, I really enjoy the increase in confidence I have with my car and the predictibility that came with this mod.

Doing this on a lift makes like a lot easier!

[vasillalov]

FBIS,

Have you seen this:

http://store.vacmotorsports.com/vac-...ver-p2493.aspx



I have the feeling that any LSD installation will require additional cooling for the final drive components because LSDs normally exhibit higher friction compared to open diffs.

[G.I.Joe]

Originally Posted by Former_Boosted_IS

G.I.Joe, I am glad the review was helpful. It is not a cheap mod, but it offers a lot of fun to driving the car. To be honest, I really enjoy the increase in confidence I have with my car and the predictibility that came with this mod.

Doing this on a lift makes like a lot easier!

It most certainly was helpful to me

No, it's not a cheap mod, but IMO this car should never have left the factory without it. I can't wait to track the car in the spring with the Quaife.

[Former_Boosted_IS]

Originally Posted by G.I.Joe

It most certainly was helpful to me

No, it's not a cheap mod, but IMO this car should never have left the factory without it. I can't wait to track the car in the spring with the Quaife.

The only thing I can think is that BMW was worried the 335i would hurt the sales of the M3 already and an LSD would just make it worse. Either way, it is a problem we can fix and that is a good thing.

[G.I.Joe]

Originally Posted by Former_Boosted_IS

The only thing I can think is that BMW was worried the 335i would hurt the sales of the M3 already and an LSD would just make it worse. Either way, it is a problem we can fix and that is a good thing.

I agree, I think that's exactly why they didn't put it in there

[Former_Boosted_IS]

Originally Posted by G.I.Joe

I agree, I think that's exactly why they didn't put it in there

Modding is a joy though to do. It gives your car a unique foot print that makes the car really your own. I love driving down the street knowing that no one really owns the same car as me. Unfortunately, my wallet doesn't like it as much. LOL!

[G.I.Joe]

Originally Posted by Former_Boosted_IS

Modding is a joy though to do. It gives your car a unique foot print that makes the car really your own. I love driving down the street knowing that no one really owns the same car as me. Unfortunately, my wallet doesn't like it as much. LOL!

There's always room for improvement isn't there?

Whether it be my cars, computers, mountainbikes, you name it, they have all been homebuilt and/or "custom" in one way or another. Some of us just don't dig "normal" I guess. It's a lifestyle

[dbjb]

Originally Posted by vasillalov

FBIS,

Have you seen this:

http://store.vacmotorsports.com/vac-...ver-p2493.aspx



I have the feeling that any LSD installation will require additional cooling for the final drive components because LSDs normally exhibit higher friction compared to open diffs.

Thats pretty cool but man... $800?

[rbaldwin28]

Quaife was the best mod I have done. It just gave the most back to the overall performance of the car. It was a no brain-er for me with a bolted final drive $1,800 installed. Got lucky. Still not sure what to do with the open diff though maybe sell it.

[Ensi]

Originally Posted by Former_Boosted_IS

BMW doesn't not suggest doing that and therefore I cannot really say that is an acceptable way to do it even if it worked well for you. This is not meant as a shot toward you, just information.

All good, I just can't see any possible way it could hurt anything by not removing the driveshaft. The shop I borrowed the AR wrench from who has done 5 now said he has never removed the driveshaft. To each his own I guess.

[Former_Boosted_IS]

Originally Posted by vasillalov

FBIS,

Have you seen this:

http://store.vacmotorsports.com/vac-...ver-p2493.aspx



I have the feeling that any LSD installation will require additional cooling for the final drive components because LSDs normally exhibit higher friction compared to open diffs.

I have seen it, but I do not have it at this point. Maybe in the future?

[G.I.Joe]

I just had my Quaife LSD installed today. Wow. Just wow.

The weather here is around 0 C (32F) and very wet today. I only drove about 15 miles home after the install, and so far only made a few hard pulls in 1st and 2nd gear (I have a 6MT gearbox), but I reckon with these winter tires, I have about as much grip on a soaking wet road now, as I did on a bone dry road without the LSD

No additional noise or other issues, just much, much better grip. The comments I have seen about the car changing behavior with the LSD is absoulutely true. It takes a LOT more to make it go sideways when cornering, and it's much easier to keep on a straigth line when accelerating hard in the wet.

Can't wait for warmer weather and summer tires and then the track

[desean81]

Great Write up. This is a big help. In the process of installing a wavetrac unit at the moment.

You mention tightening everything to BMW specs, do you have a list of the torque specs for the diff install?

[swifty]

I'm a noob and this might sound like a dumb question but if I install a LSD the way OP did, will the dealer be able to tell fm a quick glance under the car while on the lift?

[Former_Boosted_IS]

Originally Posted by desean81

Great Write up. This is a big help. In the process of installing a wavetrac unit at the moment.

You mention tightening everything to BMW specs, do you have a list of the torque specs for the diff install?

I don't off the top of my head, but I strongly suggest buying the Bentley Service manual. Best money I have ever spent on this car!

[335okc]

Originally Posted by Former_Boosted_IS

Cornering Performance

I felt this was probably going to be the area where the Quaife LSD shined and I was definitely right. During hard cornering, the weight is always transferred toward the outside of the vehicle and that inevitably means you are always low on traction on one tire. This has been particularly troubling for me because I always felt scared to get into the throttle during and especially exiting corners because of how easily I could lose control of the rear of the car. I was very excited to test this area. The results here simply blew me away. The rear of the car no longer feels loose when I am accelerating during cornering and exiting the corners. It is almost difficult to describe how different the car reacts now in the entire corner. I can really push the car through the corner and snap out of the exit so much faster, almost like how my coilovers created stability from a suspension standpoint. While the front is hugging the road, you can accelerate to the limits of the suspension so much easier. It is simply exhilarating to drive the car like this. The spirited windy road experience is so much better now. Straight line acceleration is all about that feeling you are being pressed back in the seat. Now, I can get that feeling more dynamically through cornering and I absolutely love it. I am now looking for twisties to hit, so I can feel that snap as I accelerate out of the corners.

FBIS, do you mind explaining how the LSD make the rear more planted?
i'm having the same problem with the rear always wanting to go out and i'm not sure if LSD is the solution to that. how does the physics work?
i know with LSD and enough throttle, you can make the car "oversteer" toward the apex, which is a good thing if you can control it.

[nafoo]

Originally Posted by 335okc

FBIS, do you mind explaining how the LSD make the rear more planted?
i'm having the same problem with the rear always wanting to go out and i'm not sure if LSD is the solution to that. how does the physics work?
i know with LSD and enough throttle, you can make the car "oversteer" toward the apex, which is a good thing if you can control it.

I think this may help in your journey to enlightenment.

http://www.e90post.com/forums/showthread.php?t=670174

"Why do you want a Quaife LSD?
Improved acceleration, traction and stability. Rather than using clutch plates as a method of operation, the Quaife ATB uses sets of floating helical cut gear pinions that run in pockets and mesh during normal driving. Should one of the driven wheels start to spin however, the helical gears start to generate a torque bias thanks to the axial and radial thrust of the helical gear pinions in their pockets. The result is a progressive transfer of torque away from the spinning side of the axle to the driven wheel, which is now capable of transmitting a greater proportion of torque. Unlike a plate style LSD the Quaife unit delivers performance without the need for strip downs and rebuilds. There are no plates or gears to wear or break and the ATB units retain standard vehicle lubrication."

[335okc]

Originally Posted by nafoo

I think this may help in your journey to enlightenment.

http://www.e90post.com/forums/showthread.php?t=670174

"Why do you want a Quaife LSD?
Improved acceleration, traction and stability. Rather than using clutch plates as a method of operation, the Quaife ATB uses sets of floating helical cut gear pinions that run in pockets and mesh during normal driving. Should one of the driven wheels start to spin however, the helical gears start to generate a torque bias thanks to the axial and radial thrust of the helical gear pinions in their pockets. The result is a progressive transfer of torque away from the spinning side of the axle to the driven wheel, which is now capable of transmitting a greater proportion of torque. Unlike a plate style LSD the Quaife unit delivers performance without the need for strip downs and rebuilds. There are no plates or gears to wear or break and the ATB units retain standard vehicle lubrication."

Thanks for the link and the explanation. While i already understood how the LSD works, i'm still not sure how it improve rear traction on cornering. wouldn't it mean that the outside wheel is now facing even more torque and end up spinning also?

[AlterZgo]

Originally Posted by 335okc

Thanks for the link and the explanation. While i already understood how the LSD works, i'm still not sure how it improve rear traction on cornering. wouldn't it mean that the outside wheel is now facing even more torque and end up spinning also?

No. It sends more power to the wheel with the most traction.

[piaa]

does anyone have the torque spec for the hex nuts and drive shaft nuts as the differential bolts please

[Dave W.]

Originally Posted by piaa

does anyone have the torque spec for the hex nuts and drive shaft nuts as the differential bolts please

Diff mounting bolts; 2 front bolts 100Nm/74 ft-lbs.
Rear diff mounting bolt 165Nm/ 122ft-lbs.
Axle to diff flange torx bolts 55Nm/ 38 Ft-lbs. BMW recommends new bolts here since there's locking serrations on the bolt flange that get flattened each time it's tightened.