[SteveC]

Still running in, but now getting to the point I'm venturing a little higher up the rev band.

Coming off a motorway entered a nice long, wide, dry, curving slip road, so clicked into sport and gave it some gas. Was not prepared for the 'scalded cat' take-off combined with tightening radius, but committed as I was I had to stay on the gas and I can tell you guys you could really feel that diff working. Not as progressive or 'transparent' as an M Diff, but pretty damned good non-the-less. You can feel it transferring torque to keep everything going forwards and at no time did I feel anything less than comfortable, despite the levels of energy going into and through those back wheels. The car makes you feel like an expert, although it was probably 25% driver, 75% BMW! There are not many cars with this kind of midrange power. The M5 and M6 must be animals

[Madgambler]

Standard 'Open' Electronic diff or modified Quaife/Wavetrack?

[SteveC]

Standard. I was planning to buy a Quaife at some stage but now I'm not sure. It would certainly be a lot more progressive on track, but on road, where you're nowhere near 10/10th the standard unit seemed pretty damned good. On the other hand 1 bend is not exactly a definitive test

[Shrader]

hmm this is good to know as Im still looking into this ( do i need a diff) dont suppose you know the effects of the TC and the amount of slippage you get. im guessing that Sport / + allow for more wheel spin before the rear braking effect ect ..

I do get a bit confused with how the TC works and then the all off only then giving you the Ediff effect ( unless im wrong)

i suppose I should go and have a play at my local dealers as im ready to go and order one now but they are not much use as explaining how this all works. Im used to simple LSD equipped cars with and without TC over the years !

[ovekvam]

I always used to equip my cars with LSD, and was planning to do the same with the F20. After testing the car, I have found out that the stock system is working surprisingly well, even for track driving, so I will keep it. To test it properly, you should select DSC Off.

[SteveC]

Thanks for the tip on DSC. I actually wasn't planning on testing it at all....I've been running the car in in comfort and this was really just the first time I'd tried Sport mode as I wanted to stiffen up the damper rates...wasn't really prepared for such a major change in throttle mapping!

[Shrader]

Cool , yes please report back how you get on

[westphone]

In town or on the highway I can't feel the benefit of a closed LSD even if there is one.

However, with DSC OFF on a mountain road you should be able to tilt that driver/BMW=25/75 scale more to the driver's favor. More so if it's raining. However it tends to snap away from the driver (or my poor skill hard to catch the car) than the gradual drifting away when I am too liberal with with the throttle. I'd like a closed LSD still, but then the cost for me is becoming difficult to justify with this car. YouTube shows talented drivers can drift the car; I did get "pure lucky" and drifted once or twice

Have fun and please make sure there is enough run off area

[TMP]

I felt the lack of diff today - twice i got the inside rear wheel spinning.

[Shrader]

"I felt the lack of diff today - twice i got the inside rear wheel spinning"

i thought the braking effect of the tc id supposed to sort that out?

[ovekvam]

Originally Posted by Shrader

"I felt the lack of diff today - twice i got the inside rear wheel spinning"

i thought the braking effect of the tc id supposed to sort that out?

Yes, the e-diff will brake the inside wheel. If they car is not in DTC or DSC-Off mode, the engine power will also be temporarily reduced.

[TMP]

Originally Posted by ovekvam

Yes, the e-diff will brake the inside wheel. If they car is not in DTC or DSC-Off mode, the engine power will also be temporarily reduced.

Car was in sport+, so rear stepped out nicely before I straightened up.

[ovekvam]

Originally Posted by TMP

Car was in sport+, so rear stepped out nicely before I straightened up.

If the rear stepped out, the outside wheel was also spinning. The e-diff has done its job.

[TMP]

Originally Posted by ovekvam

If the rear stepped out, the outside wheel was also spinning. The e-diff has done its job.

No, inner wheel first, (as I had all the windows down, so could hear/feel it. Then the car slide...

[ovekvam]

Originally Posted by TMP

No, inner wheel first, (as I had all the windows down, so could hear/feel it. Then the car slide...

Yes, the e-diff transfers torque to the outer wheel, which will make the rear end slide. A mechanical, limited slip differential does the same thing, just quicker. In that case you would hardly hear the inside wheel spinning before the car was sideways.

[ttimbo]

Just to clarify on this:

The standard Dynamic Stability Control system DSC includes the anti-lock braking system (ABS), the Dynamic Traction Control system (DTC), the Cornering Brake Control system (CBC) and the Dynamic Brake Control system (DBC). These capabilities are now complemented by additional features such as the Brake Assistant, Fading Compensation, Dry Braking functionality and a Hill Start Assistant. In DTC mode, the response thresholds of the driving stability control system are automatically set at a higher level. This makes pulling away on loose sand or in deep snow far easier. In addition, controlled slippage on the drive wheels gives the vehicle the ability to dynamically oversteer when negotiating bends. When DSC mode is off, the Active Differential Brake (ADB-Sport) on the rear axle is activated. To optimise traction during acceleration in tight bends, a carefully calculated braking force is applied to any drive wheel which the system detects as slipping, to enable the remaining drive wheel on the axle to continue to power the vehicle forwards.

[Shrader]

Surely

"To optimise traction during acceleration in tight bends, a carefully calculated braking force is applied to any drive wheel which the system detects as slipping, to enable the remaining drive wheel on the axle to continue to power the vehicle forwards."

You want this all the time? the other aids are more restrictive before you turn them off to get a simulated diff

This is the only thing bugging me , i don't want to have layers of TC just on / off please and so i end up driving about with DSC OFF all the time

Anyone know if i you did fit a real diff the TC behaves the same ? that i suppose is the holy grail question. If fitting a Quaife diff makes little difference to how the cars TC is applied then it could not really help as you cannot turn everything off

[ovekvam]

Originally Posted by Shrader

Anyone know if i you did fit a real diff the TC behaves the same ? that i suppose is the holy grail question. If fitting a Quaife diff makes little difference to how the cars TC is applied then it could not really help as you cannot turn everything off

I don't think that would be a problem. A real LSD like Quaife would do the same thing as the e-diff, just quicker and better. That means the e-diff would not need to do much, as it is already done by the Quaife.

In the special cases where the Quaife struggles, like when a driven wheel is temporarily airborne, the e-diff would give it a helping hand.

[Shrader]

Cheers ovekvam , my current ride is a renaultsport Megane which has a Torsion bias diff and its brilliant. TC comes in when needed but very loose so allows you plenty of slip before it applies any brakes or if you hit TC. Otherwise you can feel the power shifting from left to right to give you full grip.

However if one wheel is airborne or just cannot grip then you still get a spinning wheel but then the braking helps the re distribution. Unlike clutch diffs the gear driven ones dont need any servicing but dont lock up.

Ive no problem having a diff fitted but really want to see what other 135 drives are experiencing as it just maybe all good with what BMW fit. Ive had 2 test drives now and am not able to test the car as I would like i tried to mess about to get a feel for the traction settings but the sales chap started to get upset !

[ovekvam]

Originally Posted by Shrader

Ive no problem having a diff fitted but really want to see what other 135 drives are experiencing as it just maybe all good with what BMW fit. Ive had 2 test drives now and am not able to test the car as I would like i tried to mess about to get a feel for the traction settings but the sales chap started to get upset !

The traction control is fine for everyday driving, but for sport use it is better to leave it off. The e-diff is working surprisingly well on our 116i for track driving and ice track drifting. You can tell it is slightly slower reacting than a real LSD (maybe more like a viscous unit), but when it is active, it is perfectly weighted. It is possible to go really eariy on the throttle in corners.

There are some videos on Youtube showing drifting with the M135i that would not have been possible without a decent differential setup.

Still, compared to the rather extreme Megane, I guess the BMW will be more conservative and less sporty in most ways (except for the fact that it has RWD).

[SteveC]

Originally Posted by Shrader

Ive no problem having a diff fitted but really want to see what other 135 drives are experiencing as it just maybe all good with what BMW fit. Ive had 2 test drives now and am not able to test the car as I would like i tried to mess about to get a feel for the traction settings but the sales chap started to get upset !

No big surprise there! I'd not be that chuffed if a sales guy tried to demonstrate how well the various traction settings worked.

[Shrader]

Haha well I wasn't trying to do anything mental , just be a bit more liberal coming off roundabouts ect otherwise how on earth are you supposed to feel the difference !! haha they want their £30k+ i want to see what im getting