Alfa Romeo Giulia Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
85 Posts
Discussion Starter · #1 ·
What does the Active Suspension do?
Do I want the limited slip diff?
I drive spiritedly in winding mountain roads several times/week.

Already added the 19" Ti Sport Package.

Thanks!!
 

·
Registered
2018 Q4 with Fiamenghi Ti exhaust, Race Mod, and Tecnico wheels.
Joined
·
7,671 Posts
What does the Active Suspension do?
Do I want the limited slip diff?
I drive spiritedly in winding mountain roads several times/week.

Already added the 19" Ti Sport Package.

Thanks!!
Active suspension allows the damping rate to be adjusted. It has two settings in dynamic mode and only one setting in Natural or Advanced Efficiency modes. Without it you get a single "compromise" setting. With it, you get a softer ride in N and A and your choice of softer or harder ride in D.

Limited slip diff improves rear wheel traction by reducing the chance of just one wheel breaking loose. You can accelerate harder in a straight line or in a curve. Traction control and ESC attempt to do something similar by reacting to wheel slippage and applying the brakes, but it does not work as well as a mechanical LSD.

LSD cuts in when a wheel starts to slip.
Traction control cuts in when a wheel starts to spin.

LSD can still allow one wheel to spin. LSD are rated with a "torque ratio" that indicates the maximum ratio of torque that can be applied to the wheel. If one wheel has 0 traction, the torque ratio doesn't matter and the other wheel gets 0*ratio = 0 torque (not quite exactly, due to internal friction in the LSD but pretty close). When this happens the mix of LSD + traction control shines, because the traction control can *gently* apply the brake on the spinning wheel to send plenty of torque to the wheel with traction. This makes the transition to higher traction conditions much smoother compared to traction control alone.
 

·
Registered
Joined
·
790 Posts
Ti Performance Package Deconstructed

What does the Active Suspension do?
Do I want the limited slip diff?
I drive spiritedly in winding mountain roads several times/week.

Already added the 19" Ti Sport Package.

Thanks!!
It does add two items: Active Suspension and Mechanical Limited Slip Differential.

Active suspension adds an additional feature, borrowed from the Quadrifoglio btw, to adjust the dampening of the shocks when in Dynamic mode. When you select D, all four corners of the Ti get firmer and you get another level of road feel. During hard cornering, say on your mountain twisties, this suspension change results in less roll-out, as dampening is dynamically adjusted to keep the car flat and planted. A switch mounted in the center of the DNA nob permits the driver to defeat performance "firm" and select the same "soft" ride one knows in N and A mode, and on non Ti Perf Pack Giulias.

I've found on my car that I can pull 1.00+ G's in D mode "firm" and can only pull .91 G's with "soft" selected. So, simply said, Active Suspension lets the car approach its' cornering potential and is essential for a mountain driving enthusiast! Your 19" Ti Sport package already provides the low-profile tires to get maximum benefit from this system.


Mechanical Limited Slip Differential (LSD) is an enhancement to the rear differential (and on the Giulia Q4, it is mostly a rear drive car for pavement performance driving) to compensate for wheel slip without resorting to brake-based "Stability/Traction control" overrides by the chassis computer. Basically, it dynamically reduces wheel slip by diverting power to the wheel that grips from the wheel that is slipping. In mountain driving, both extremely tight turns and unequal traction conditions (gravel/sand) are likely events that the LSD handles beautifully.

In my weekly canyon drives near Denver, my Ti Perf Pack LSD gets a workout on the marked 15mph hairpins and frequent sandy runoff that're on the roadway. The result is very little wheel slip and predictable lines exiting corners. On track conditions, the LSD enhances high-speed traction leading to the same predictable and swift exit from turns that we experience on mountain roads.

Unfortunately the Ti Performance Package on Q2 or Q4's seems to be a rare option. The $1,200 sticker price is the best value of all Giulia options IMHO. Aftermarket LSD's run between $2-3K and active suspension systems sell for $1,200-2,000 themselves, when feasible as a retrofit.

Hope this helps,
 

·
Registered
Joined
·
85 Posts
Discussion Starter · #4 ·
Thank you very much lockem, and mtb.ck for the thorough explanation. I'll look for a Ti with both 19" Sport Package and Performance Package. There's no point in having just one.
 

·
Registered
2020 Alfa Romeo Giulia Sport Ti AWD
Joined
·
7,383 Posts
I think "active suspension" is misleading. "Adjustable dampers" would be more accurate.
 

·
Registered
Joined
·
1,186 Posts
Misleading how? It is active. The Chassis Domain Control module, only present on cars with active suspension, constantly gathers data from 5 accelerometers (two front hub accelerometers, two front body accelerometers, plus an accelerometer built into the CDCM), and controls the dampers accordingly. The damper button is not just a choice between two different but fixed hardness levels. It's a choice between two different calibration profiles, both of which involve continuous damper control by the CDCM.
 

·
Registered
2020 Alfa Romeo Giulia Sport Ti AWD
Joined
·
7,383 Posts
In the end, only damper jounce and rebound are affected. Active suspension is more than that and in purest form follows skyhook theory. There's plenty to read on the subject. Here's a sample: https://www.edmunds.com/car-technology/suspension-iii-active-suspension-systems.html. Bose had a very impressive system that went even farther that unfortunately never made it into production (computer controls of the time were not as advanced as they are today). The closest thing to it on the road and in showrooms was Nissan's: http://activesuspensionsystems.com/whyforq45.html. Adaptive dampers are quite common and work well. Please note that I have no complaints about my Giulia's suspension.
 

·
Registered
Joined
·
1,186 Posts
I still don't see how you believe it is not active suspension. It does exactly what your link describes.

The problem with the Bose system was, in addition to the cost, the power it needed, and the weight of the system. They eventually gave up and adapted the technology for trucker seat suspension.
 

·
Registered
2020 Alfa Romeo Giulia Sport Ti AWD
Joined
·
7,383 Posts
Maybe I'm too fixated on skyhook theory (which, to my knowledge, no present production automotive suspension achieves). I see that as meaning wheels will be lifted over bumps rather than spring and dampers reacting to them. If the marketing department insists on using the word "active", so be it.

https://www.revolvy.com/main/index.php?s=Skyhook%20theory&item_type=topic
 

·
Registered
2020 Alfa Romeo Giulia Sport Ti AWD
Joined
·
7,383 Posts
Ah, Lommel. https://www.fordlpg.com/en/

Many manufacturers and suppliers are working on predictive suspension systems, and some are already available: http://www.thedetroitbureau.com/2013/06/high-tech-suspensions-smooth-out-the-bumps/
 

·
Registered
2020 Alfa Romeo Giulia Sport Ti AWD
Joined
·
7,383 Posts
This is from when Magneti Marelli first introduced the SDC suspension system (at the time, on the Alfa Romeo Mito and Lancia Delta).

http://www.ukintpress-conferences.com/conf/08vdx_conf/pdf/day_1/grecogiordano.pdf

Giulia's system is a direct descendant of that.
Yes, Skyhook principles are applied. This is an example of good "bang for the buck". Much of what is desired has been achieved for a fraction of the cost and weight. Actuation, however, is still limited to damping.
 

·
Registered
Joined
·
124 Posts
Maybe I'm too fixated on skyhook theory (which, to my knowledge, no present production automotive suspension achieves). I see that as meaning wheels will be lifted over bumps rather than spring and dampers reacting to them. If the marketing department insists on using the word "active", so be it.

https://www.revolvy.com/main/index.php?s=Skyhook theory&item_type=topic
The new Audi A8 is going to have exactly what you described, lift the wheel over pot holes and bumps.
 

·
Registered
Joined
·
332 Posts
Old thread I know but something I haven’t really seen addressed.


I can feel that the damper setting in N and the soft setting in D are about the same. Is the A mode even softer? I have an ‘18 and I swear it feels like A mode is even further mushier than the N. Maybe I’m just feeling what I want to feel but trying a few times on certain roads yeilded similar results. Unless this has more to do with how the suspension ‘adapts’ in each respective mode. Hmmmmm
 
1 - 15 of 15 Posts
Top