The lsd is a clutch type from ZF and is only installed in the rear axle. Lock up percentages are apparently 23% on accel and 45% on decel. There is not an lsd in the front because the front doesn't always get power. According to Andy Forrest, time attack guy with absurd subaru builds, the effectiveness of a front lsd is reduced when the torque bias greatly favors the rear axle, as is the case in the Giulia. According to other members on the forum, Q4 with the lsd is a money setup. Generally it reduces asr/tc/esc intervention and allows you to enjoy the car mostly free of electronic spoils.

 

Thanks much for the clarification!

 

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.

 

Totally agree. ESC never intervenes and the handling is very neutral.

 

This bums me out. I wasn't aware the LSD was not standard on the Sport Q4 Ti until after I picked it up. Anyone know if it's a direct swap or would you need a whole new pumpkin, axles, etc versus the open?

 

As it's also tied into the electronic systems, I would doubt it's a simple/cheap swap ......

 

LSD of any kind is must on any performance car. would not own one without it. Even though the Sport doesn't have the ELSD like my Quadrifoglio, its still better than an open diff.

 

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.

 

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!

Well, you definitely have to push the car to feel the LSD, but once you do, it is both confidence inspiring and addictive.

 

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.

 

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?"

 

See also :
http://www.giuliaforums.com/forum/289-alfa-romeo-giulia-general-discussion/8529-rear-wheel-drive-vs-q4-awd-4.html

 

Yes thats correct, only the QV has the ELSD unit

 

I know, I just meant that it could be that a number of the other systems (traction control, abs, electronic dampers, body control, .....) might need to be aware of the presence of an LSD to adapt control strategy to take maximum advantage.

 

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.

 

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...

 

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.

 

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.

 

That's exactly the part most people don't know (especially the dealers): the adaptive suspension adapts CONSTANTLY - no matter which setting you are in.

Sadly I don't have a chance to try one at my dealer.
(Only base spec diesels in and around my location...)

 

Centerline International has an LSD on their web site now. (They are a supporting vendor here by the way)

https://www.centerlinealfa.com/catalog/limited-slip-differential-giulia

 

Yup, Centerline carries it too. Sweet setup. I support all the Alfa parts guys and hope you all will too. All the alfisti tend to spread the love around to keep all the parts houses going. Most times, one parts guy won't have it but the other will.

 

when a 1000$ option costs ~6000$ hahaha

talking about suspension +LSD

 

cool.

 

Just chiming in that I did make sure my Giulia Q4 had the LSD option...

I'll have to reread this thread but I should also add that I was very specific with wanting the LSD on my car as I didn't want to wonder what it would have been like to have it had I NOT optioned for it...seems like I'm not the only one who felt that way...

I should also note that my experience the car def feels great around corners...truly confidence inspiring...my only other experience was a base Giulia with RWD I had as a loaner...and I want to say I def felt a difference with the cornering.

 

Wonder how much the labor would be on the install?

 

maybe ~6-8hr job. I don't plan to pay anyone to do it.

 

I notice that the owners manual lists the following differentials:

RDU 195
RDU 230-TV
RDU 230 LSD
RDU 210/215 LSD

There apparently used to be a catalog or spreadsheet detailing each on the ZF website but it has been removed.

Which are we supposing is the the differential listed by centerline?

Let me make a few assumptions here. Coming from the Subaru world I would think that the numbers above refer to the diameter of the ring gear in each rdu. Also, zf apparently calls these rear drive units, hence the name. I would suspect the centerline unit is the 210/215 LSD. The 230tv I believe is the QVs torque vectoring unit. If that is the case I would think it would be overkill for the 2.0 cars to have the 230lsd with the same size differential (sans the planetary differentials and electric motors) as the QV. But if that is the case, good on Alfa.

I’m just trying to reach a conclusion here. Because, if the unit in the 2.0 giulias are the 210/215lsd then they may be the same or a similar unit to the zf hag rdu 215 utilized by the f3x 3 series. If that is the case, and bmw purchased the unit from zf as Alfa does, there are several aftermarket options for Lsds

Turner motorsports offers upgrades for the zf hag 215 diff, link provided below. Now the biggest issue with these is that zf welds the ring gear to the differential carrier. Thus, machining is necessary to provide an aftermarket lsd a means to affix itself to the ring gear. At any rate these are their options:
https://www.turnermotorsport.com/p-...f3x-335i435i-manual-limited-slip-and-gearing-differential-upgrade/?pdk=AQEBAQEB

Again I’m making a lot of assumptions but I feel like I’ve researched as thoroughly as I could to get to this point. Perhaps the rdu 195 is the q4 front diff? But I believe that is supplied by magna and would have a different name. Perhaps the 195/210 are open diffs and European cars are offered with different sizes than us cars? The 215lsd could be for 6 speed diesel cars and the 230lsd could be the clutch type listed at centerline.

In the end, I’m not sure but thought this might be helpful. The ti performance pkg unit is certainly better than an open diff but it won’t be anything like an OS Giken. Perhaps @MacGeek could provide further insight?

 

My understanding is about the same as yours, including the guesses.

The three digit number is the diameter of the ring gear. The general assumption is, 'the larger the ring gear the stronger the differential'. I will argue that the ring gear is not the weakest link. The side gears and spider gears are the weakest link.

Most open differentials have two spider gears and I've seen them break, generally from being hammered on doing drag race starts. Generally speaking, an LSD of the same size will have four spider gears making it twice as strong, able to withstand more abuse.

Having a bolt-in ring gear allows for changing the ring and pinion so you can change the gearing. This isn't something that can be done on the fly, or even at the track. The serious racer would have multiple pumpkins (differential housing) all ready setup with different gearing. Then simply swap pumpkins at the track. Purpose built track cars are designed with quick change read-ends as well as quick change transmissions and transmission gearing.

 

A little necromancy here but I think I have further (assumed/deduced) insight into the diff situation. I did some digging through the dodge/jeep parts catalog and discovered that the SRT Durango and Grand Cherokee come with a RDU 230 equipped with clutch type LSD with electronic control. Hellcats/Demons have the same 230mm differential, but only the Durango and GC have cases that resemble the mounting hardware seen on Giulia differentials. Some Charger owners have swapped these differentials, or older non-electric clutch type LSDs, into their open-diff cars. However this requires a change in axles as well. Since the OEM/Centerline LSD is plug and play, not requiring lager axles, I am assuming that the following is an accurate breakdown of the differential mystery:

RDU 195: Open front differential on Q4 cars (this is also the front differential on Durango/GC).
RDU 210 "elsd": Open rear differential on non ti performance pack Giulias (misleading as elsd is brake actuation).
RDU 210/215 LSD: Clutch/plated type LSD on Ti performance pack cars (23% lock on accel 46% decel).
RDU 230 LSD: Simply the open differential situated between the TV planetary gear-sets on Quads.

This all needs to be confirmed, but I have spent a truly dumb amount of time trying to figure this out. If this is indeed the case then there may be a few possibilities. A company called Racing Diffs has confirmed that the 210/215 LSD can accept their upgraded clutches that offer increased lock. They also stated that until they can get their hands on an open diff 210 RDU, they cannot confirm that aftermarket LSDs that fit BMWs will necessarily fit Giulias. Apparently, ZF tends to have small variations between spider gears on their open differentials. And even if they can be equipped to open diffs, the ring gears are still welded to the carrier, necessitating modification.

Again, just my $0.02.

 

I have also tried to get a BMW specialist who machine ZF diffs to fit Quaiffe. They were not interested in trying for Alfas.

When I put the question to Quaiffe this was their response
"We have looked into it, but the issue is that we are not looking to get involved in the machining off of the crown wheels, so we looked at whether we could source new crown wheels from Alfa Romeo (or directly from ZF) but were unable to purchase them.
It would need a customer that has capability to carry out the machining on a case by case basis, which means a high up front capital investment.
In short, it is not currently financially viable for us to develop an ATB diff for this car.

If you have any further questions or I can be of any assistance in the future, please don't hesitate to contact me."

So until a specialist thinks there is a market for this and invests its not going to happen. Did speak to an independent that offers Quaife for most other alfas. The have had a look into this and did some research with Quaife. Quaife will only do batches of 10 so need an order of at least 10 people. He first would need an open Diff that quaife would then destroy to make the first diff. So would come from a scrapped car. Then once the first had been manufactured it would then be a case of swapping out the diff from each car 1 and then machining off the crown wheels to attach the new ATB diff.

All got a bit complicated. So we decided to drop it. If the numbers for an order of 10 are out there and someone sees a scrapped open diff car selling parts. Happy to pick up and see if there is a way to order. Im UK based so if people were in US they would need to find a company able and willing to machine then weld back on the quaife diff local to them.

 

Thank you for sharing that, it is very helpful. I know Bimmerworld and Turner Motorsports do, or used to, install a variety of LSDs or TBDs into diffs with the welded ring gear. Of course the cost is substantially greater to have that done. It appears that Wavetrac offers this service for 210/215 equipped BMWs. I know they don't have the pedigree of Quaife, but I believe they are the only torque biasing differential that can still operate when one wheel is lifted/loses traction.

It would seem that for the foreseeable future, the best option is the factory ZF unit and shimming or installing aftermarket clutches if greater lock is desired.

 

Hi @Crisdeto I'm in the process of retrofitting a LSD on my RWD Giulia and was wondering if the Clutch upgrade you mentioned is worth the buy.
Have you or for that matter any1 else on the forum installed this ? How's the feeling/difference?

Thanks!