[freedomgli]

I think it's helpful if people would use the manufacturer's terminology when describing certain features so as not to invite confusion. For instance, only the Quadrifoglio has the ZF Torque Vectoring Differential. However, all Giulias are equipped with an electronically controlled engine-torque limiting and foundation brake-based Traction Control System (TCS) with a programmatic feature known as Brake Limited Differential (BLD) as described below. Virtually all automakers employ a similar strategy using the TCS/ESC system.

Traction Control System (TCS)

The system automatically operates in the event of slipping, loss of grip on wet roads (hydroplaning), and acceleration
on one or both drive wheels on roads that are slippery, snowy, icy, etc.

Depending on the slipping conditions, two different control systems are activated:
If the slipping involves both drive wheels, the system intervenes, reducing the power transmitted by the engine.

If the slipping only involves one of the drive wheels, the Brake Limited Differential (BLD) function is activated, automatically braking the wheel which is slipping (the behavior of a self-locking differential is simulated). This will increase the engine torque transferred to the wheel which isn't slipping.

 

[freedomgli]

Also the owners manual (both 2017 and 2018) lists an optional eLSD for the non-Quadrifoglio Giulia models in the fluid capacities section. Does anybody have any idea what that is about?

I simply chock that up to typical automaker behavior where misprints and mistakes in the owner's manual are commonplace and don't necessarily indicate that the feature is/was/ever will be available in your particular market or anywhere else for that matter.

 

[Racer Z]

Man, this thread really makes me feel like a wuss! I mean, I just can't seem to go fast enough on the street to the point where traction in the Q4 feels like a limiting factor. Maybe it's a lack of skills and courage, or the generously open MI curves, but I'm just not comfortable flinging the car through turns at speeds high enough to make traction loss an issue...and my passengers certainly aren't either, because people think I'm frighteningly aggressive already!

I definitely know that loss of grip sensation from my RWD Porsche 928's (one of which is supercharged and put 479hp down on a Dynojet), but I've never been able to get that sensation in an AWD car, I think because the limits are far beyond my ability to test them.

Anyway, I hope to do some performance driving ed in the Giulia and hopefully my build my skills to the point where I can appreciate what an LSD would bring to the performance mix.

Going that fast on public roads is not exactly sane. Not saying I've never done it, but... Personally, I go to the track (road coarse) about four times a year. I can go as fast as I want or feel comfortable. On public roads I leave plenty of margin for error. One never knows what's around the corner on a blind turn. I've encountered boulders, stopped cars, deer, dogs, bicyclist's. Not to mention that I don't want to be that guy that overshoots the turn, crossing into oncoming traffic and wads my car. Where I live, the curvy roads have a cliff straight up one side and a cliff straight down the other. Plenty of Yahoo's have bounce off the cliff and fallen off the other.

In the case of performance driving, the LSD, or lack of, is most noticeable at turn exit when the inside tire is still unweighted and full power is being applied. I track a 240z and when I first started tracking it had an open diffy. I could feel the inside tire spinning at certain turn exits. When I upgraded to a clutch type LSD, that slipping sensation went away and I could tell that I had faster (slightly) exit speed.

All Giulias do have ESC (electronic stability control). Part of this is the ability to dab a single brake to help control wheel spin. With an LSD, the Limited Slip unit will (should) kick in before the ESC realizes there is wheel spin. The ESC does not know there is an LSD unit (Ti only). The Ti has a purely mechanical LSD while the Quad has an integrated Electronic LSD (eLSD).

You can't do a burn-out from a standing stop. I've tried. Even if you power-brake, you can't. Well, you can spin the rears for about half revolution, but then the engine cuts power and you just fall on your face.

 

[stocki]

Can someone confirm that the ESC, CDC or BCM has no knowledge about the presence of an LSD (talking about the 2.0 Engine)?
I find that hard to believe...

 

[Racer Z]

Racer Z,

I tried to do a search, but it seems that the tool will not let me search on a user name + keyword, and it doesn't want to show me results from prior to 9/17.

I am quite certain that I asked MacGeek circa July or August 2017 if the traction control system was "aware" that there is an LSD installed in the car and his answer was "yes". The key being that if a wheel on an LSD axle is slipping the system only needs to apply the brakes about 1/4 as hard to stop the wheel from spinning as compared to the action needed to stop the spinning with an open diff axle. We did not dive into how the system was aware of the situation. In any case, less aggressive application of the brakes by traction control means more control for the driver, more power to the ground, and less side-to-side jerking.

The owners manual lists an eLSD for non-Quadrifoglio models. It is unclear what that is or if any cars have it.

I have no idea of the cost of the LSD differential unit, but the option also includes the adaptive suspension. A set of the adaptive shocks is "only" $4400 from my dealer parts department. Is $1500 for the option a "bargain"? Maybe not in the long term when it comes time to replace those shocks.

The "in-house" search tool sucks. The 'Google' search tool in the upper right corner works well.

The Quad has an integrated eLSD (electronic limited slip differential). Being electronic, it's safe to assume that the ESC is fully aware.

The Ti has a purely mechanical LSD and the ESC has no knowledge that it exists. The LSD will (should) kick in before the ESC can sense any wheel slip. The ESC should never need to dab a brake if the LSD is working correctly.

By the time my active shocks wear out, one could assume that there will be aftermarket alternative replacements. I suppose another question would be, "Do I have to use eShocks or can I use standard shocks?"

 

[stocki]

Great news - kind of opens the door for aftermarket diffs with more locking percentage than the stock LSD (2.0 engines, again).

 

[Racer Z]

Great news - kind of opens the door for aftermarket diffs with more locking percentage than the stock LSD (2.0 engines, again).

Right. And, upgrading an open diffy should be easy once the aftermarket companies get going.

 

[stocki]

Right. And, upgrading an open diffy should be easy once the aftermarket companies get going.

Great news. Makes it a lot easier to find a car for me. In my region pretty much no one buys the performance package (2800€). Everyone around here has a Diesel with black cloth seats.

I can already see the usual suspects (Quaife) tinkering on their island...

 

[lockem]

Great news. Makes it a lot easier to find a car for me. In my region pretty much no one buys the performance package (2800€). Everyone around here has a Diesel with black cloth seats.

I can already see the usual suspects (Quaife) tinkering on their island...

Please reference
http://www.giuliaforums.com/forum/177570-post59.html
Question number 4.

This doesn't mean that upgrading to an LSD without altering the programming will fail, but I expect that it does mean that you will get better performance from the OEM LSD.

 

[Tazio!1901]

Racer Z,

I tried to do a search, but it seems that the tool will not let me search on a user name + keyword, and it doesn't want to show me results from prior to 9/17.

I am quite certain that I asked MacGeek circa July or August 2017 if the traction control system was "aware" that there is an LSD installed in the car and his answer was "yes". The key being that if a wheel on an LSD axle is slipping the system only needs to apply the brakes about 1/4 as hard to stop the wheel from spinning as compared to the action needed to stop the spinning with an open diff axle. We did not dive into how the system was aware of the situation. In any case, less aggressive application of the brakes by traction control means more control for the driver, more power to the ground, and less side-to-side jerking.

The owners manual lists an eLSD for non-Quadrifoglio models. It is unclear what that is or if any cars have it.

I have no idea of the cost of the LSD differential unit, but the option also includes the adaptive suspension. A set of the adaptive shocks is "only" $4400 from my dealer parts department. Is $1500 for the option a "bargain"? Maybe not in the long term when it comes time to replace those shocks.

Regarding the adaptive suspension, does this aid both handling and improve ride quality?

 

[freedomgli]

Regarding the adaptive suspension, does this aid both handling and improve ride quality?

Alfa certainly market the adaptive suspension as improving both dynamic performance and ride quality. However, in my limited test driving, I didn't notice that much difference between the various suspension settings on the Ti Sport AWD w/ Ti Performance Package, nor did I notice much difference when compared to the ride/handling balance on Giulias equipped with the standard (non-adaptive) shocks. I'm sure more time behind the wheel driving over varied road conditions would better illuminate the differences. But in my mind, if there were differences, they are subtle. As always, your mileage may vary and everyone is going to have their own opinion. I could definitely notice the mechanical LSD, but the shocks weren't that noticeable to me. This is in marked contrast to the DNA knob, which provides substantially different throttle and transmission response depending on the mode you're in.

The adaptive suspension system may even improve after a break-in period. The car I test drove had very low mileage.

 

[stocki]

Please reference
http://www.giuliaforums.com/forum/177570-post59.html
Question number 4.

This doesn't mean that upgrading to an LSD without altering the programming will fail, but I expect that it does mean that you will get better performance from the OEM LSD.

That makes more sense to me.
Seems a bit unlikely, that a car in 2018 doesn't know which diff it has fitted.

 

[Tazio!1901]

Thanks Freedomgli!

 

[freedomgli]

Thanks Freedomgli!

Definitely test drive a car with the adaptive suspension and decide for yourself. At the end of the day, I chose a car without the Ti Performance Package because I placed a higher priority on my preferred exterior color choice than I did on the LSD/ adaptive shocks. As for cost, if I was still into auto-x I would definitely think the $1200 for the LSD was worth it. But since I only drive on the street these days and my opportunities for aggressive cornering are rather limited, I didn't feel like I was giving up too much.

 

[Racer Z]

Regarding the adaptive suspension, does this aid both handling and improve ride quality?

I haven't driven both types of shocks back-to-back. Driving both types had a few weeks between. In my first test drives, I definitely liked the Active Suspension in stiff setting over standard shocks or Active Suspension in soft mode.

On the track, the suspension will leave lot to be desired, and that is true for most cars, including my 4C. In the canyons a few weeks ago (Giulia), I was wanting stiffer shocks, stiffer anti-roll bars, and possibly stiffer springs. For 'touring' style driving, the Active Suspension is nice as it is.

I don't know what makes the Active Suspension tick. Is it controlled by raising/lowering the voltage? If so, can we increase the voltage safely?

 

[jwq2]

....
I don't know what makes the Active Suspension tick. Is it controlled by raising/lowering the voltage? If so, can we increase the voltage safely?

from elswhere:

The system goes by many names: Synaptic Damping Control (SDC), ALFA ACTIVE suspension, Continuous Damper Control, etc. The twin-tube shock absorbers are made by ZF-SACHS. They are controlled by the Magneti Marelli Chassis Domain Control Module (CDCM). There are five active damping sensors on the vehicle. There are two sensors located on each of the front steering knuckles, and there are two sensors located behind each headlight underneath the hood. There is one sensor located in the CDCM, which is located in the trunk of the vehicle. As such it can monitor longitudinal and lateral acceleration, pitch, roll and yaw rates.

Each shock absorber has an electronically controlled solenoid valve that is connected to the CDCM via electrical connector and associated wiring harness communicating via the high-speed 500 kb/s CAN-CH (CAN-C2) data network. The system monitors the solenoid valve temperature, current (out of range), short to ground or open circuit, signal plausibility, all the various accelerations, individual wheel speeds, brake pressure, throttle pedal position and rate, engine speed, steering angle, transmission state, eLSD activation, torque vectoring module activation, active aero activation, etc.

Rear shock absorber [SDD] pn 68318575AA (same left and right)
Front right shock absorber [SDD] pn 68336084AA
Front left shock absorber [SDD] pn 68336085AA

I'm not sure why Tech Authority and Mopar Parts refer to the active suspension with code SDD but they do.

Here is an old Magneti Marelli technical presentation
http://www.ukintpress-conferences.com/conf/08vdx_conf/pdf/day_1/grecogiordano.pdf

Here is an old ZF technical presentation
https://www.zf.com/corporate/en_de/magazine/magazin_artikel_viewpage_22101416.html

 

[pipposera]

I can attest to the fact that the Q4 with LSD setup is money for sure. Grip around corners is fantastic. The LSD combined with the 100% rear wheel bias makes for a super sporty and light handling feel. Plus with the active suspension that comes with the performance package, it really makes the car in my opinion.

Based on what I was told by the dealership, the active suspension makes them softer, not more sporty. in other words, it is useful to soften the suspention when you drive on a of road/bumpy road. So it should not bring any value at the track

 

[lockem]

from elswhere:

Rear shock absorber [SDD] pn 68318575AA (same left and right)
Front right shock absorber [SDD] pn 68336084AA
Front left shock absorber [SDD] pn 68336085AA

Are those part numbers for QV, 2.0T, or both?
Some others indicated that part numbers are different in the USA versus Europe. Assuming that is correct, are those Euro or Mopar numbers?

 

[Il_Conte]

Based on what I was told by the dealership, the active suspension makes them softer, not more sporty. in other words, it is useful to soften the suspention when you drive on a of road/bumpy road. So it should not bring any value at the track

The dealership doesn't know ****.. as usual.
The setting is softer than standard when you are in A and N mode, but stiffer than standard when you are in D mode.
Also, they adjust in real time on road conditions.

 

[mtb.ck]

Agree... dealer is on a small red planet...

The dealership doesn't know ****.. as usual.
The setting is softer than standard when you are in A and N mode, but stiffer than standard when you are in D mode.
Also, they adjust in real time on road conditions.

Take an active damper car out and drive the same set of hard braking, tight corners with serious acceleration in between those corners, notice the lack of body roll the lack of dive and squat versus the non-dynamic suspension car. It is a night and day difference, that even a moron can feel in the first three turns.

Only a dealership that hasn’t tried the two cars in real world performance driving situation would dumb down the realities of this terrific tech in their comments. Even a pothole in N mode can demonstrate the difference.