[Lancelot]

Hi

Just to share the latest evolution of the active hybrid, in case it is of any use to some of you someday:

1/ F80 carbon struts braces

This mod is detailed in this thread here http://f30.bimmerpost.com/forums/sho....php?t=1234698



Basically it consists in upgrading the struts bearings to F80 with additional bolting holes, replacing the minimal F30 brace with a pair of aluminium brace that holds the upper part of the chassis in a much better way, and a carbon fiber reinforced part that hooks to the nose of the chassis.

It's a bolt on mod that is rather easy to do, you can even do without the expensive carbon part to begin with in my opinion. I got it new from a private seller for 2/3rd of the new price, not sure why he was selling but it was obviously unused.

2/ H&R anti-roll bars
Great results, not overly expensive parts, the front one makes the car feel like it's on rails and corner flat, the rear one introduced more bumpiness i'm getting used to, as well as a better controlled body roll and less understeer.

The real pain with the ARBs is BMW built their F30s subframes in such a way that you need to unmount the entire subframe (while holding the 250kg engine in place) to get to the front ARB to change it. Took hours to do.

Note how thin the OEM rear bar is compared to the H&R 12mm OEM vs 19mm H&R. Front wasn't that dramatically different, 25 vs. 29mm.


front bar in position:


FWIW, if I were to do it again, I think I'd go for Eibach or KW that have similar front bars, but slightly less stiff rear ARB at 16mm vs 19mm.

3/ Quaife differential

The operation consists in exchanging the differential with another one that has been converted to a Quaife by Birds Auto in the UK, keeping the same casing as the BMW open differential.
So my shop, Bavarian (http://www.performance-store.com) orders a differential to them, when make the exchange, and they send mine back to Birds, which presumably is used as basis for another conversion for someone else with the same diff.

Original diff:

Modified differential:

Shafts awaiting their new diff:


Overall very happy with this mod too, the out of corner traction is impressive, and generally the power delivery feels significantly more consistent. It is actually useful in a daily drive too in this wet season, with puddles and rotting leaves all over the roads making traction very inconsistent.

One thing I am wondering is wether it is useful, useless or harmful to code out the e-LSD function as advised here (if even possible on F30) :
http://www.onelapx1.com/blog/how-to-...w-actually-fun
section 'Electronic Differential (AX_Ref_Diff_Lock)'

My understanding was that the mechanical actual LSD will actually prevent the eLSD to come into play, except perhaps with a wheel in the air, in which case braking the spinning wheel is actually a useful complement to the mechanical LSD.

Finally in search for useful info on differentials, here's my top list of useful info:
"Differentials - Explained"

"Exploded View - Inside the Eaton TrueTrac Differential" - which is rather similar to Quaife:

"Understanding Limited Slip differentials" - describes the principle of friction LSDs, which I believe is the type offered by BMW with the M performance aftermarket part:

"Building a BMW 135i Manual Quaife LSD.wmv" - Shows how it's made

And finally, if you haven't seen it yet, our friend Chris Harris having a blast with his Quaife

[Polo08816]

Originally Posted by Lancelot

Hi

Just to share the latest evolution of the active hybrid, in case it is of any use to some of you someday:

1/ F80 carbon struts braces

This mod is detailed in this thread here http://f30.bimmerpost.com/forums/sho....php?t=1234698



Basically it consists in upgrading the struts bearings to F80 with additional bolting holes, replacing the minimal F30 brace with a pair of aluminium brace that holds the upper part of the chassis in a much better way, and a carbon fiber reinforced part that hooks to the nose of the chassis.

It's a bolt on mod that is rather easy to do, you can even do without the expensive carbon part to begin with in my opinion. I got it new from a private seller for 2/3rd of the new price, not sure why he was selling but it was obviously unused.

2/ H&R anti-roll bars
Great results, not overly expensive parts, the front one makes the car feel like it's on rails and corner flat, the rear one introduced more bumpiness i'm getting used to, as well as a better controlled body roll and less understeer.

The real pain with the ARBs is BMW built their F30s subframes in such a way that you need to unmount the entire subframe (while holding the 250kg engine in place) to get to the front ARB to change it. Took hours to do.

Note how thin the OEM rear bar is compared to the H&R 12mm OEM vs 19mm H&R. Front wasn't that dramatically different, 25 vs. 29mm.


front bar in position:


FWIW, if I were to do it again, I think I'd go for Eibach or KW that have similar front bars, but slightly less stiff rear ARB at 16mm vs 19mm.

3/ Quaife differential

The operation consists in exchanging the differential with another one that has been converted to a Quaife by Birds Auto in the UK, keeping the same casing as the BMW open differential.
So my shop, Bavarian (http://www.performance-store.com) orders a differential to them, when make the exchange, and they send mine back to Birds, which presumably is used as basis for another conversion for someone else with the same diff.

Original diff:

Modified differential:

Shafts awaiting their new diff:


Overall very happy with this mod too, the out of corner traction is impressive, and generally the power delivery feels significantly more consistent. It is actually useful in a daily drive too in this wet season, with puddles and rotting leaves all over the roads making traction very inconsistent.

One thing I am wondering is wether it is useful, useless or harmful to code out the e-LSD function as advised here (if even possible on F30) :
http://www.onelapx1.com/blog/how-to-...w-actually-fun
section 'Electronic Differential (AX_Ref_Diff_Lock)'

My understanding was that the mechanical actual LSD will actually prevent the eLSD to come into play, except perhaps with a wheel in the air, in which case braking the spinning wheel is actually a useful complement to the mechanical LSD.

Finally in search for useful info on differentials, here's my top list of useful info:
"Differentials - Explained"

"Exploded View - Inside the Eaton TrueTrac Differential" - which is rather similar to Quaife:

"Understanding Limited Slip differentials" - describes the principle of friction LSDs, which I believe is the type offered by BMW with the M performance aftermarket part:

"Building a BMW 135i Manual Quaife LSD.wmv" - Shows how it's made

On snow - Open vs. limited slip diff

And finally, if you haven't seen it yet, our friend Chris Harris having a blast with his Quaife

Could you ask your shop what they used to place the axle shafts back into the differential?

[Lancelot]

Originally Posted by Polo08816

Could you ask your shop what they used to place the axle shafts back into the differential?

Not sure to understand exactly, but the shafts go in place directly, the crowned part at the end of the shaft fits into the differential?

[Lancelot]

Originally Posted by Lancelot

Not sure to understand exactly, but the shafts go in place directly, the crowned part at the end of the shaft fits into the differential?

Perhaps check these posts too with specific information on the topic:

http://f30.bimmerpost.com/forums/sho...&postcount=139

[Polo08816]

Originally Posted by Lancelot

Not sure to understand exactly, but the shafts go in place directly, the crowned part at the end of the shaft fits into the differential?

Originally Posted by Lancelot

Perhaps check these posts too with specific information on the topic:

http://f30.bimmerpost.com/forums/sho...&postcount=139

I'm the guy who posted that information.

However, the BMW tool is about $450+ to do that procedure. I was wondering if anyone else has done a DIY and used an alternative tool that isn't nearly as expensive.

There's a $30 tool to pop the axle shafts out of the differential.

The potential issue is getting the axle shafts back in the differential.

[Lancelot]

Ah i see now. I'll ask next time.

[Lancelot]

Just had a look to the PDF, i haven't seen them use the special tool, rather more standard tools, not sure if that means something for the durability of the mount of the shafts at all.

[Polo08816]

Originally Posted by Lancelot

Just had a look to the PDF, i haven't seen them use the special tool, rather more standard tools, not sure if that means something for the durability of the mount of the shafts at all.

If you look at the last 2 posts I made, there's a special tool "33 5 125" that is basically a clamp that goes around the indent on the axle shaft. I believe they use to serve as a service to tap the axle shaft back into place in the differential.

[Kabrich]

Subbed

[Gr-Racing]

Great post, How much for the quaife diff?
im guessing it must be better than the M perfomance lsd upgrade .

[Lancelot]

Overall 2500 eur (subject to british pound fluctuations) fitment and parts, so i think less than the M performance, but on the AH3 we don't have the option of the M performance differential anyway, as we don't have the same differential as the 335/435 unfortunately.

That being said i think i would have gone quaife even if it were available due to the nature of the differential which i think is better suited to my needs than the clutch-plate type.

[oceanview]

Originally Posted by Lancelot

Hi

3/ Quaife differential
Overall very happy with this mod too, the out of corner traction is impressive, and generally the power delivery feels significantly more consistent. It is actually useful in a daily drive too in this wet season, with puddles and rotting leaves all over the roads making traction very inconsistent.

Welcome to the "club"

One thing I am wondering is wether it is useful, useless or harmful to code out the e-LSD function as advised here (if even possible on F30) :
http://www.onelapx1.com/blog/how-to-...w-actually-fun
section 'Electronic Differential (AX_Ref_Diff_Lock)'

My understanding was that the mechanical actual LSD will actually prevent the eLSD to come into play, except perhaps with a wheel in the air, in which case braking the spinning wheel is actually a useful complement to the mechanical LSD.

+1 that's my experience as well.

I usually drive in "normal" or "sport" mode. Even going rough out of corners I hardly see the DSC light (eLSD) coming on. The Quaife is doing such a good job.
SPORT+ mode I almost never use in regular street drive. (which would allow more wheel spin)

I was concerned that eLSD would start to regulate in "Normal" or "Sport" mode, before you can feel the Quaife working, but it's not the case.
Now, when driving up a hill into and into a corner, when accelerating the car will softly tend to over steer. Much better driving control than without LSD!

[Lancelot]

Originally Posted by oceanview

Welcome to the "club"


+1 that's my experience as well.

I usually drive in "normal" or "sport" mode. Even going rough out of corners I hardly see the DSC light (eLSD) coming on. The Quaife is doing such a good job.
SPORT+ mode I almost never use in regular street drive. (which would allow more wheel spin)

I was concerned that eLSD would start to regulate in "Normal" or "Sport" mode, before you can feel the Quaife working, but it's not the case.
Now, when driving up a hill into and into a corner, when accelerating the car will softly tend to over steer. Much better driving control than without LSD!

Yes exactly, soft and progressive, had this feeling that "if i press that throttle just a little more, fun thing are going to happen", but in a controlled manner... Looking forward to my upcoming track day next weekend

[peopleschoice1]

Great info and mods!

[Forgiven]

I really like what he has done so far, following your build now.

[bbog2008]

OP - do you think that changing the rear sway bar only would improve the handling?

[DVC]

Originally Posted by oceanview

+1 that's my experience as well.

I usually drive in "normal" or "sport" mode. Even going rough out of corners I hardly see the DSC light (eLSD) coming on. The Quaife is doing such a good job.
SPORT+ mode I almost never use in regular street drive. (which would allow more wheel spin)

I was concerned that eLSD would start to regulate in "Normal" or "Sport" mode, before you can feel the Quaife working, but it's not the case.
Now, when driving up a hill into and into a corner, when accelerating the car will softly tend to over steer. Much better driving control than without LSD!

When you see the yellow dash light coming on in Normal/Sport, that's the DSC intervening. The eLSD is not active in Normal, Sport or Sport+, it's only active in DSC-off mode (hold down DSC button for 5+ seconds). eLSD is merely the application of ABS to retard the spinning of the wheel that's losing traction... which is really a subset of the full suite of activities involved in DSC. In other words, it's one or the other.

Since LSDs/ATB diffs improve traction, they do help keep DSC from intervening, and also reduce the effect of the eLSD in DSC-off mode.

As far as coding-out eLSD, I would be interested in doing this if it were possible, as I'm really not a fan of this system at all. When I choose to go beyond the intervention thresholds of Sport+ I'd really rather have ALL nannies off!

[Lancelot]

Check this page then
http://www.onelapx1.com/blog/how-to-...w-actually-fun

[Bee Pee]

Originally Posted by Lancelot

Check this page then
http://www.onelapx1.com/blog/how-to-...w-actually-fun

I'd be wary about the above as its more about how to de-code an x drive to be more like a RWD track rat !!!

Read it in conjunction with this thread below as its more relevant to F series RWD cars

http://www.2addicts.com/forums/showt...1231483&page=1

[oceanview]

Originally Posted by DVC

When you see the yellow dash light coming on in Normal/Sport, that's the DSC intervening. The eLSD is not active in Normal, Sport or Sport+, it's only active in DSC-off mode (hold down DSC button for 5+ seconds). eLSD is merely the application of ABS to retard the spinning of the wheel that's losing traction... which is really a subset of the full suite of activities involved in DSC. In other words, it's one of the other.

Since LSDs/ATB diffs improve traction, they do help keep DSC from intervening, and also reduce the effect of the eLSD in DSC-off mode.

As far as coding-out eLSD, I would be interesting in doing this if it were possible, as I'm really not a fan of this system at all. When I choose to go beyond the intervention thresholds of Sport+ I'd really rather have ALL nannies off!

DVC
I start to get confused now. Reading the Owner's Manual I see the following:
DSC Dynamic Stability Control
The concept
DSC prevents traction loss in the driving wheels when driving away and accelerating.
DSC also recognizes unstable vehicle conditions, such as fishtailing or nose-diving.


My understanding:
DSC "on" actually blocks wheel spin completely by reducing throttle power
DSC "on" and then also switching DTC "on" gives you more wheel spin (this setting is only available in "Comfort mode")
DSC and DTC are blocking the rear wheels with brake activities. "eLSD?"

Switching DSC "off" with holding the DSC will eliminate DSC and DTC function.
So please tell me, what "feature" will control the wheel spin now?
Are you saying, that when "Comfort mode" and switching off the DSC some other undocumented electronics chime in?

My feeling i.e. when driving on snow whit DSC off is, there is nothing active regulating except ABS for braking.
Am I wrong?

[DVC]

Originally Posted by oceanview

DVC
I start to get confused now. Reading the Owner's Manual I see the following:
DSC Dynamic Stability Control
The concept
DSC prevents traction loss in the driving wheels when driving away and accelerating.
DSC also recognizes unstable vehicle conditions, such as fishtailing or nose-diving.


My understanding:
DSC "on" actually blocks wheel spin completely by reducing throttle power
DSC "on" and then also switching DTC "on" gives you more wheel spin (this setting is only available in "Comfort mode")
DSC and DTC are blocking the rear wheels with brake activities. "eLSD?"

Switching DSC "off" with holding the DSC will eliminate DSC and DTC function.
So please tell me, what "feature" will control the wheel spin now?
Are you saying, that when "Comfort mode" and switching off the DSC some other undocumented electronics chime in?

My feeling i.e. when driving on snow whit DSC off is, there is nothing active regulating except ABS for braking.
Am I wrong?

DSC encompasses a whole suite of activities that includes pulling engine power and applying ABS to individual wheels based on sensors that interpret wheel spin and vehicle yaw rates.

In our cars, DTC (whether engaged via the DTC button, or Sport+ mode) is a component of DSC with reduced intervention parameters... i.e. it allows a bit of wheel spin, as well as some slip angle (depending on vehicle speed - the faster you go, the less it allows ; ) before it intervenes.

DSC-off disables DSC entirely - almost! It switches on the "eLSD" function, which is merely the application of ABS to a rear wheel that is spinning faster than the other, such that the car interprets it as losing traction (Think of it like xDrive for RWD cars). The intention of the eLSD is to mitigate the shortcoming of an open differential (whereby it fails to apply adequate torque to the non-spinning wheel, as it effectively gets siphoned off to the spinning wheel). By retarding the spinning wheel, it provides a bit of resistance within the diff, and allows the non-spinning wheel to utilize a bit of the torque. It actually does work, but not nearly as well as a mechanical LSD.

There's a good discussion on this in this thread, within which I posted this table of settings/parameters for our cars that you may find helpful.

[Lancelot]

thanks for sharing this table, most interesting. I'll try the DSC off to compare.