[R12TCH]

Just read the whole of this thread and decided an LSD is the mod I most want on my car! (after ditching the RFT's)
Think that an LSD will be much better than a remap as the power can then be used properly although the remap would probably be next on the to do list.
Have started saving up, but sounds like my car will be a welded version so will take that little bit longer!

[a1reader]

Originally Posted by R12TCH

Just read the whole of this thread and decided an LSD is the mod I most want on my car! (after ditching the RFT's)
Think that an LSD will be much better than a remap as the power can then be used properly although the remap would probably be next on the to do list.
Have started saving up, but sounds like my car will be a welded version so will take that little bit longer!

Although an LSD is pretty much essential (especially after a remap), a remap is quite simply amazing on the 335i. I'll be posting my review soon, and I too am saving for one of those Qauife LSDs

[doughboy]

Aside from the massive road traction improvements,

Having had the Quaife for 6 months, and having used it successfully to lose E36 / E46 M3's out of corners on a track day (when without it I was left floundering) I can vouch that standard 306bhp is quite a lot.

God knows what it will be like with a map....

[Alpina_B3_Lux]

Originally Posted by doughboy

God knows what it will be like with a map....

It's even better with a remap. Currently running 400+hp (tendency increasing lol) and cornering out of bends was always a time for christmas lights on the dashboard - that has changed now, although it's still not optimal due to the cold weather and my winter tires.

Alpina_B3_Lux

[zltm089]

sorry for sounding really stupid....but what is the difference between a quaiffe lsd and switching off the DSC completely? same outcome???

[a1reader]

Originally Posted by zltm089

sorry for sounding really stupid....but what is the difference between a quaiffe lsd and switching off the DSC completely? same outcome???

A limited slip differential (LSD) or automatic torque biasing LSD as Quaife call it transfers engine power to the rear wheel with most traction. DSC cuts engine power and/or applies the brakes when one of the wheels looses traction. Not quite the same.

[doughboy]

Originally Posted by zltm089

sorry for sounding really stupid....but what is the difference between a quaiffe lsd and switching off the DSC completely? same outcome???

Z, if I could get the same result turning off DSC why would I, or anyone for that matter, bother spending £1500 on a diff?

Have a read - http://en.wikipedia.org/wiki/Limited_slip_differential

[zltm089]

Originally Posted by doughboy

Z, if I could get the same result turning off DSC why would I, or anyone for that matter, bother spending £1500 on a diff?

Have a read - http://en.wikipedia.org/wiki/Limited_slip_differential

Yeah, hence why I wanted to know, what is the difference between switching off the DSC and a fitted lsd....

otherwise people like you and Tony or anyone else wouldn't spend £1500 on a quaiffe lsd when they can simply switch off the DSC by pressing a button for 5 seconds...

I wanted to understand how the car reacts with an LSD v/s DSC off... what sort of differences etc?...

[zltm089]

guess I got a bit confused with the DSC off debate and was thinkin that the LSD was somewhat related to wheels spinning/ oversteer ....where DSC also comes into play with wheel spin and oversteer...

[doughboy]

Originally Posted by zltm089

guess I got a bit confused with the DSC off debate and was thinkin that the LSD was somewhat related to wheels spinning/ oversteer ....where DSC also comes into play with wheel spin and oversteer...

Sort of,

DSC comes into play to PREVENT wheels spinning and oversteer from happening in the first place by REDUCING engine power output and BRAKING individual wheels as necessary, So turning if off will allow you to do whatever you wish (or don't wish) to happen.

LSD alters the way the wheels will provide driving force to the road, it stops just one wheel spinning aimlessly and wasting all the energy (or DSC cutting in very easily) as a standard diff does and makes the power always split between BOTH wheels, with most power going to the wheel with MOST grip instead.

So in simple terms, neither wheel will spin until so much power is being transfered that BOTH wheels start to spin, this is quite hard to do and allows you to get TWICE the power down before wheel spin occurs.

This also helps with drifting etc for those that wish. But for mere mortals like me is just means much more power down before DSC needs to intervene.

So the LSD just allows you to accelerate much more quicky with triggering the DSC.

[flip4335]

Originally Posted by doughboy

So the LSD just allows you to accelerate much more quicky with(out) triggering the DSC.

+10000

On an open diff, which every non-M, 3-series possesses, power is equally distributed to both wheels....all the time! Never mind that one wheel would lose traction. When that happens and you push the accelerator, the wheel with no traction continues to spin, albeit, uncontrollably, while the other wheel with the same (torque) power hunkers on. Sensing this, the DSC applies the brakes to the wheel with traction to even out the power--essentially slowing down your car at the most inappropriate times--in order to regain control of the car.

So, when you enter a corner or sweeping ramp and hit a wet spot or lift the inner rear wheel (thus, losing traction) with DSC on, the nanny controls brake the outer wheel and rather than accelerating through the ramp, you slow down to watch everyone else pass you by if you are tracking.

When you turn off DSC, you now have the ability to spin out because it can't control the loss of traction to one wheel. The wheel with the grip now has the ability to induce oversteer and eventual loss of control if you don't know how to control oversteer (which every drifter relishes...and wants).

When I make a sharp turn with my mechanical Quaife LSD, I can feel the diff shift most of the power to the outer wheel with traction, while minimizing the torque to the inner wheel, and I can accelerate harder out of the turn, rather than slowing down until both wheels regain equal traction. I also make a tighter turn, which allows me to explode through the turn if both rear tires maintain their grip...and this is with DSC on! No lights, no epilepsy-inducing strobes, just complete control.

With LSD and DSC off in the wet, the ride is both exhilarating and stressful if you are new to the physics of vehicle dynamics. Now the vehicle behaves the way older cars did before the invention of nanny controls and threshold braking was part of every student driver's education.

LSDs should also be touted as a mechanical safety feature, because they ensure complete predictability beyond the limits of adhesion.

My ride with Quaife approaches M3 performance without the M3 price and expense. Call it .... M3 Lite .... hahaha ... because I don't plan to track, but I want the comfort of enhanced performance in smaller doses, knowing that I could outmaneuver an equally powerful, open-diff 3-series ... if I wanted....like an M3!

[SoYank]

Originally Posted by flip4335

LSDs should also be touted as a mechanical safety feature, because they ensure complete predictability beyond the limits of adhesion.

My ride with Quaife approaches M3 performance without the M3 price and expense. Call it .... M3 Lite .... hahaha ... because I don't plan to track, but I want the comfort of enhanced performance in smaller doses, knowing that I could outmaneuver an equally powerful, open-diff 3-series ... if I wanted....like an M3!

The safety aspect of the Quaife is the primary reason I got mine. I'd decided on it even before considering the trips to Nürburgring.

In the past eight days here in Ccolorado I've been driving in three snowstorms yet not seen the DSC light up once. Hard acceleration on the dry roads is exhilarating while feeling the LSD shift between the wheels.

Best mod I've done, even over the ARBs and the brakes.

[HP Autosport]

Originally Posted by SoYank

The safety aspect of the Quaife is the primary reason I got mine. I'd decided on it even before considering the trips to Nürburgring.

In the past eight days here in Ccolorado I've been driving in three snowstorms yet not seen the DSC light up once. Hard acceleration on the dry roads is exhilarating while feeling the LSD shift between the wheels.

Best mod I've done, even over the ARBs and the brakes.

Can you please educate everyoen else on this subject? Most do not understand how important the LSD is!

[SoYank]

Originally Posted by HP Autowerks

Can you please educate everyoen else on this subject? Most do not understand how important the LSD is!

From a safety aspect, in my opinion, the application of an LSD is critical in modern driving with the speeds and lack of courtesy and/or attention from other drivers. When trying to enter a fast moving yet not gridlocked road, whether from a sliproad or sidestreet, traffic can change between the time you commit to entering and when you're actually up to speed and that Escalade driver with the cell phone shoved in her ear who was in the center lane suddenly decides she'd rather be in your lane. Now you've got the choice of accelerating away or bailing onto the shoulder to avoid the collision. This is not the time for the car to apply the brakes or cut engine power just because one wheel encountered a patch of broken up pavement, water, ice, or gravel. With the LSD, when that happens the other wheel, instead of sitting idly by, is putting the whole of the available power onto the road. This gets you out of the predicament much quicker and safer. Even with the LSD, when the conditions are ripe, the DSC will still be there functioning as BMW intended. It just takes a lot more for it to show up.

[flip4335]

+1.....Well said....and a fact of life for modern day drivers, especially cell phone distracted drivers

Agreed on Safety.

The Quaife -- or any mechanical diff for that matter -- should actually be touted as a safety feature that everyone must have. What happens when the software fails on an e-diff? Mechanical diffs would always be there.

A Quaife, Wavetrac, Torsen, Drexler, Giken -- you name it -- would be light years better than a software solution that wears down your brakes and could possibly fail!

Side benefit 1: the frequency of replacing your brake pads would certainly diminish, especially for you thrill seekers, with the installation of a LSD.

Side benefit 2: Your car will become safer, and at the same time, sportier! A pleasant dichotomy of contrasting themes... safer... sportier... yin... yang... balance!

Side benefit 3: You would enjoy sleeper car stealthiness to unsuspecting drivers who view your 3er with arrogant disdain....

LSD for safety...and FTW!

[m1bjr]

Another view.

An ATB is not always goign to save your ass on the road.
In fact an ATB diff can put you out of shape where an open diff wont.

I doubt most of you run on the road with the ATB installed and DSC off?

Having owned recently an S2000 with a rear ATB diff and also an R26 with a front ATB diff I can say the results are often unpredicatable.
I would never call it a safety feature, more of a track day tool.

Cross a white line with the power down on either car and as the torque is shifted violently between wheels it can get VERY squirrely, an open diff car wont do this it will spin up a wheel - no big deal.
Go out and play hard in loose conditions, with DSC OFF and report back you still think its a great safety feature

[E92Fan]

Originally Posted by m1bjr

Another view.

An ATB is not always goign to save your ass on the road.
In fact an ATB diff can put you out of shape where an open diff wont.

I doubt most of you run on the road with the ATB installed and DSC off?

Having owned recently an S2000 with a rear ATB diff and also an R26 with a front ATB diff I can say the results are often unpredicatable.
I would never call it a safety feature, more of a track day tool.

Cross a white line with the power down on either car and as the torque is shifted violently between wheels it can get VERY squirrely, an open diff car wont do this it will spin up a wheel - no big deal.
Go out and play hard in loose conditions, with DSC OFF and report back you still think its a great safety feature

Virtually all my driving is with an LSD and the DSC system switched off. I don't find the rear end squirrely at all - yes, you can feel the power shift left/right as the wheels find traction over bumps, but the upside in power delivery accelerating through corners and the throttle adjustability that results from having an LSD far outweigh the sometimes lively nature of the rear end.

[mexicomark]

Where can i get one fitted in Northern Ireland ?

Or will i have to go over to the mainland - i'm heading over for the Ford Fair in August. Anyone fit them near Silverstone .

[doughboy]

Originally Posted by m1bjr

I would never call it a safety feature, more of a track day tool.

Cross a white line with the power down on either car and as the torque is shifted violently between wheels it can get VERY squirrely, an open diff car wont do this it will spin up a wheel - no big deal.

I've not noticed any squirrely behaviour. Much more squirrely IMO with the open diff and DSC franticaly braking and cutting power.

I always have DTC on, and somtimes DSC off, the Quaife unit never seems to 'violently' shift torque.

Originally Posted by mexicomark

Where can i get one fitted in Northern Ireland ?

Or will i have to go over to the mainland - i'm heading over for the Ford Fair in August. Anyone fit them near Silverstone .

Best to book into Birds near Heathrow, get it fitted while you wait, no exchange costs or shipping either. Some might say Birds know what they're doing too

[Alpina_B3_Lux]

Originally Posted by doughboy

I've not noticed any squirrely behaviour. Much more squirrely IMO with the open diff and DSC franticaly braking and cutting power.

I always have DTC on, and somtimes DSC off, the Quaife unit never seems to 'violently' shift torque.

Best to book into Birds near Heathrow, get it fitted while you wait, no exchange costs or shipping either. Some might say Birds know what they're doing too

Exactly my experiences, too.

Alpina_B3_Lux

[m1bjr]

Originally Posted by E92Fan

can carry greater speed safely through corners.

On a race track like Brands Hatch, if I were to race James, he wouldn't see which way I went after just a few corners.

Is this just bar room talk then or do you have some datalogger numbers to back it up?
Have you compared these cars side-by-side on a circuit?

I have had a few cars with various LSD but this would be a big outlay on something that simply 'feels' better.

If anyone has some hard data then please post up, thanks as I might be tempted.
£1200 fitted is cheap, the ATB unit itself normally retails around the £900 marker.

[E92Fan]

Originally Posted by m1bjr

Is this just bar room talk then or do you have some datalogger numbers to back it up?
Have you compared these cars side-by-side on a circuit?

I have had a few cars with various LSD but this would be a big outlay on something that simply 'feels' better.

If anyone has some hard data then please post up, thanks as I might be tempted.
£1200 fitted is cheap, the ATB unit itself normally retails around the £900 marker.

Those who know me will attest to the fact that these sentiments are not mere bar room talk and have been proven beyond any shadow of a doubt on the toughest tracks in Europe

The LSD does 'feel' better, as you put it. It also allows a competent driver to extract the most out of a balanced chassis, without the over-exuberant intrusion of DSC systems. And on a track, I'm carrying a good 20% more exit speed through a corner over a similarly specced 3er without an LSD.