[AlfaAndy]

I overheard at the local Alfa Romeo Launch event, the Sales Manager speaking to a prospective buyer. I heard them in passing and didn't have the opportunity to speak to him directly about this. In a nutshell he said, that if you purchase the AWD option, you don't need, AND, it would be a waste of money, to purchase the limited slip option (in the Performance Package).
Not having the personal knowledge of all of the characteristics and operations of the Giulia AWD system and the torque-vectoring system and the non defeatable active traction control system, maybe he is correct. Or, maybe he is incorrect.
I have been led to believe that the Giulia AWD operates in 100% RWD until (a certain amount of) slippage is detected and then the ECU activates the AWD system (and then as needed, the torque-vectoring) and then the front wheels are driven. I would think that in comparison, an open differential would trigger the AWD sooner than a limited slip differential. Thus, the Giulia AWD would have better traction and operate in 100% RWD mode longer (as with spirited driving) with the limited slip option. As most of us would agree (I think), it is more desirable to operate in 100% RWD as long as possible, before the front wheels become driven.
Has anyone had this discussion when ordering their Giulia?
Does anyone have an opinion on this?

 

[dcpattie]

I've also wonder this. Generally speaking most AWD systems have some sort of LSD build into the system. I had a post months ago on this forum wondering why this package (Performance pkg) was not heavily discounted on Q4 (AWD) models. I never got a good answer.

 

[Alfalessalfisti]

I would say it depends on the application. For 90% of consumers, there wont be a need for the LSD. If the car is strolling around suburbia with occasional snow it might be unnecessary with all TCS and ASR functional. HOWEVER, I would absolutely order the LSD. I've driven several AWD systems and am well aware of how they function.

Today, most competitors don't offer an LSD. BMW's Xdrive and Mercedes' 4matic have a transfer case like the giulia and function just like the giulia (rwd until slip occurs). However neither offers an LSD. To get an LSD in the BMW you have to order it as an aftermarket part from M parts devision and have your dealer put it in.

Audi is the inverse. Their new quattro plus system is FWD until slip occurs. Again no LSD is offered. Select S and RS models have LSDs but the systems will default to fwd (again specific to '18 and newer cars with Quattro Plus).

On modern cars with the various safety systems, an LSD is irrelevant for most applications. Brake vectoring, TCS, and ASR will do their best to simulate an LSD to get you out of sticky situations. And honestly that's enough for navigating mild snow. However, as someone who drives two vehicles without such systems, I will always advocate for a true mechanical LSD. The fact that Alfa even offers it as an option on the Ti is an outstanding achievement.

I currently have two cars that are AWD with center and rear LSDs. Both have open front diffs (as the giulia does). I autocross both and have driven both in 2-3 inches of snow. Unlike the traditional transfer case type awd like the Giulia, Merc, and BMW, my cars cannot "decouple" drive to the front wheels. Both of my vehicles have viscous center differentials that keep torque distribution as near as possible to F50:R50 (saabaru) and F45:R55 (VR4). Mid-turn under throttle, both cars progressively trim their line nosing into the apex and nudge the rear out thanks to the rear LSD. Having a front lsd would greatly increase the "nosing in" effect on throttle.

Again it's all up to you and what you want the car to do. I strongly advocate for the LSD but completely admit that you don't NEED it.

 

[Alfalessalfisti]

I think it would be very impressive if Alfa pushed the Q4 system even farther by adding an optional one way front LSD and allowed the transfer clutch engagement to be controlled (warning, extreme subaru bias here). In normal driving, with the front differential not receiving any power, the one way front lsd would remain inactive and cause minimal parasitic drag. Then maybe offer 3 adjustments for front differential engagement leaving torque split at (F0:R100, F35:R65 and F50:R50). Having this type of setup, including front and rear LSDs, there would be minimal intervention from all the electronic nannies, guaranteeing pure, lovely, mechanical grip.

That is a pipe dream, but it would far surpass the capability of any of the awd systems offered by the Giulia's competitors.

 

[dcpattie]

I think it would be very impressive if Alfa pushed the Q4 system even farther by adding an optional one way front LSD and allowed the transfer clutch engagement to be controlled (warning, extreme subaru bias here). In normal driving, with the front differential not receiving any power, the one way front lsd would remain inactive and cause minimal parasitic drag. Then maybe offer 3 adjustments for front differential engagement leaving torque split at (F0:R100, F35:R65 and F50:R50). Having this type of setup, including front and rear LSDs, there would be minimal intervention from all the electronic nannies, guaranteeing pure, lovely, mechanical grip.

That is a pipe dream, but it would far surpass the capability of any of the awd systems offered by the Giulia's competitors.

Saab's XWD system could do this as it had an eLSD.

 

[Alfalessalfisti]

Many of the systems have the ability, but they aren't taken advantage of. XWD is a haldex system that is fwd and can shuffle 50 or 70% (I can't recall exactly) rearward. I've seen XWD cars get pretty sideways under throttle in the wet or in the snow but for extreme on-track conditions it will suffer from the same understeering issues that other haldex cars will (Golf R, any Audi with a transversely mounted engine, Volvo, etc). The only company that offers something close to what I described is Subaru with the driver controlled center differential on the STi. It can't decouple one driven axle from the other as I described, but it can vary torque distribution between F35%:R65% and F50%:R50%. The DCCD until 2018 has been a hybrid of electronic and mechanical LSD and it directs power to a helical LSD in the front and a Torsen LSD in the rear.

But, this is an Alfa forum. I'm sure the Q4 system is extremely capable. If the aftermarket can provide something similar to what I've described or at least a front LSD to compliment the rear, then there may be a stelvio in my future as well as a Giulia.

 

[JoeCab]

I've always been a big fan of a mechanical LSD on the rear axle of any car, period. Alfa started installing them as standard on the 105/115 series cars in 1972 for the US market. Traditionally, Alfa used a relatively mild 25% locking factor.

I know they are a hard sell these days. They give a real tactile sensation when powering out of a turn that is hard to describe to drivers of "appliance" cars - they don't know why they would want one, so car companies can't market them effectively. Nonetheless I am disappointed that Alfa doesn't make this feature standard on the Giulia. While the traction control and stability control do accomplish most of what a LSD does, they don't give the same feel.

 

[Gfrfan]

So Joe and Alfalessalfisti, do you think a RWD Giulia with LSD would do ok in a rainy climate with light snow 3-4 times per year (like we get in Seattle, Portland, Vancouver)?

 

[Alfalessalfisti]

I personally would say yes, especially with decent all seasons and definitely with dedicated snow tires.

 

[AlfaAndy]

So Joe and Alfalessalfisti, do you think a RWD Giulia with LSD would do ok in a rainy climate with light snow 3-4 times per year (like we get in Seattle, Portland, Vancouver)?

I agree with the others. The Electronic Traction Control systems in the newer upscale rear wheel drive cars make a huge improvement in foul weather traction. The esc system uses the electronic "throttle" and the abs system to control wheel spin and improve traction. In a rwd vehicle you also have the ability to put weight (I use 3 - 60lb. bags of tube sand, located and secured in the front most portion of the trunk) right over the drive wheels to improve traction on snow days. My wife is a public school Superintendent and she hates to call off school for snow. Her daily driver is a rwd 2001 BMW 530. that just turned 254k!. I install dedicated snow tires / wheels and use the tube sand. She gets out before the buses leave and determines whether to call off school for the day. The weight in the trunk makes a huge difference.