Retrofitting a Q2 to an existing Alfa

I got the clutch from CG motorsport in Leeds, I know of a few lads who have it fitted and its a good unit,
I'm just waiting on a new dual mass flywheel to me shipped to me from Italy now

the car already has:
20 groove red dot disks with Ferodo DS2500 pads all round
front upper, lower and rear strutbraces
Koni adjustable Suspension
Remaped to 200bhp
so the mods its getting at the moment should really set it off

Originally Posted by siralfalot

I'm just waiting on a new dual mass flywheel to me shipped to me from Italy now

Did you order the flywheel from CG also? What make is it?

BR,

nah the flywheel is a standard AR part

Can anyone advise what is weight of the Q2? I'm going to UK soon and want to pick one up.

Originally Posted by ABYSS

Can anyone advise what is weight of the Q2? I'm going to UK soon and want to pick one up.

Hi ABYSS

The standard Diff is 4'6 kg.
So i guess about 5 kg.

Chiers

Fotiz

Thanks mate.

I got to try the Q2 diff at the Ring in various weather conditions over about 20 laps.

Overall I think it was pretty good.

The downsides were
a) It didn't seem too great in the wet and span up very easily under hard cornering compared to the Autodelta diff, but in the dry this wasn't a issue and it seemed to provide good efficient traction.

b) There is a little more torque steer hunting on uneven surfaces but nothing too frightening on a track, I tended to hold the wheel quite tightly over 140mph on the bumpier bits of the ring!
Initially I felt a greater impression of the torque steer on uneven Irish minor roads, but apparenlty all Torsen diffs take a while to break (where the torque bias ratio stabilizes) so I will give it the benefit of the doubt for now on that.

c) At the Nurburgring the Q2 Torque transfer always completely collapsed at Briedshied (even in 4th gear) due to the combination of the inside wheel unloading under heavy cornering and some bumps, which definitely wasnt the case with the AD diff, but I think this was worst case for a torque biasing diff.

Overall I was very impressed even though I wasn't caning it over the kerbs yet.
The upsides were that you could feel it working instantly for minor changes in available traction between the wheels, and that for normal road use including parking it was transparent especially at full lock, and very quiet.

I'm not 100% sure of whether this diff adversely affects your ability to brake into corners to a slight extent, creating modest understeer under trailbraking.
I think my rear brake discs were beginning to warp so this would have affected my perceptions.

Overall definitely a no brainer at that price though!


Yes it weighs about 5kg, easily carryable

Cheers,
TB

Nice review Trailbraker :-)

Today I have fitted the powerflex bushes at the rear...so now with
1.Koni-FSD
2.Powerflex at front and at the rear
3. Wheel alignment, as my car was completely out of line...

The car feels glued to the road, taking corners at full acceleration the ASR stays quite, where before was going crazy.

Cornering speed is much much higher...you can do stuff the was impossible with the standard open diff.

I think that braking is also improved...

Overall the car is what I always wanted it to be in my dreams. I am really happy with the Q2, and I would recommend it to anyone. I don't thing that there is any other modification for 350Euro that can compare to it.

Originally Posted by Trailbraker

Overall definitely a no brainer at that price though!

TB

So if it lasts about as long as the AD diff (7 trackdays it was??), will you be buying these again?

I suppose for less powerful cars than yours the negatives would be even less noticeable...

On another note, since the Q2 diff doesn't fit my car, what other manufacturers besides Torsen and Quaife make limited slip diffs with gears?

Quaife is a Torsen type diff, Torsen doesn't make any difs or any products at all for that matter.

Quiafe is a "torque biasing diff", not a Torsen diff

Torsen diffs are a seperate make of torque biasing diff made by Torsen - who are the company that makes the Q2 diff for Alfa and lots of other manufacturers, although Q2 is an Alfa specific marketing term.

Torsen and Quaife are direct competitors.

Cheers,
TB

Originally Posted by Alexandrus

Quaife is a Torsen type diff, Torsen doesn't make any difs or any products at all for that matter.

Hehe I don't know, to be fair to AD they have offered me a FOC replacement, and have also slightly changed how the diffs are machined so the expectancy could be longer next time.
If the lifetime of both was infinite and the maintenance zero then I think it would be the AD diff.


I'll have a better idea of the differences the next time I do my local track, I'll be on type-R tyres then and this will probably stress the Q2 diff more, I have only used it with road tyres to date at the Ring.
I should be able to compare telemetry too.


I confess that I'll be slightly nervous taking kerbs under high throttle with it though - I would like to just enjoy the car for a little while
(My "diff labour" budget is glowing red!)

Cheers,
TB

Originally Posted by Cuore_Sportivo_155

So if it lasts about as long as the AD diff (7 trackdays it was??), will you be buying these again?

I suppose for less powerful cars than yours the negatives would be even less noticeable...

On another note, since the Q2 diff doesn't fit my car, what other manufacturers besides Torsen and Quaife make limited slip diffs with gears?

Actually, as far as I know, Torsen only sells the right to use their patented technology designs(to Alfa for instance, for the Q2 and Q4, to Audi for most of the quattro systems, and so on), and not manufacture anything, but I could be wrong.

Heres the link with the background info on :

http://www.torsen.com/

They do appear to actually manufacture diffs (including Audis Quatro system, Subaru STi, and the Hummers!) and even offer custom manufacturing/development services.

Of course it is possible that Alfa got a manufacturing license like you say, I don't know.

Cheers,
TB

Good to hear your thoughts on the diff sounds like your are fairly happy with it despite its flaws, I'd imagine it was more durable than a clutch type diff, spreading the torque over numerous rods seems pretty solid compared to shafts riding the ramps to compress the clutches, course if the diff casing is exploding under your torque it won't matter .

I've noticed torque steer on mine in the rough stuff but have put that down to worn car syndrome, the GT has kept together better than my old GTA which under similar levels of enjoyment had a new suspension part every 3k (typically ARB links/bushes ) but having done 50k without changing a single part I think the the old GT is showing its age.

The telemetry between the Q2, Quaife and AD will be interesting to see.

Sandy Have you had any time to get yours on track yet?

Yup its defintely a world better than the standard open diff!
BTW on track I didn't notice any funny behaviour when unwinding the steering after apex, it seemed to feel natural enough to me.

The Madeno diff (reputed to be a Quaife) in Peter K's car seemed to perform a bit better than the last Quiafe diff I tried in Bmoferrals GTA.
I think that is just down to the stiffer suspension and dampers on Peters car, its very well setup as a fast road car and the car had less roll, good ride quality too!
It certainly didn't spin its inside wheel to the same extent that I experienced with the Quaife before.

My car would be a bit more edgy than Peters, especially with my new very stiff rear ARB, stiffer again springs and dampers plus more lowering - so the torsen diff would have had things a little more in its favour - nonetheless my impressions are that I would prefer the Torsen diff over the quaife - it really did handle my torque quite well

Cheers,
TB