Retrofitting a Q2 to an existing Alfa

Thanks for the info Chris, much appreciated.

I was hoping the Q2 had a higher torque bias ratio than the Quaife ATB, which at least was the case for at least one make of car that I could find stats for.
I felt the torque bias ratio for the 2.5v6 Quaife felt a bit low for track use on the GTA when I tested it in a friends car - certainly user friendly though and quietly efficient.

I have also heard reports of quaife diffs breaking in less powerful (but still heavily modified) GTAs than my own - don't know how much to trust that info yet but I'm inclined to go for the cheap option since I was impressed with a recently posted video by Guezen of a certain 3.0V6 156 with a Q2 diff at the ring.
I was hoping that a Torsen diff designed for the largish torque of a diesel should be stronger than a diff designed for a modestly torquey 2.5v6. Not sure if that is neccessarily the case though!

Cheers,
TB

Originally Posted by Chris155

Quaife probably have an ATB diff on the shelf at the moment BTW, expensive I know but possibly stronger than a Q2?

can you elaborate on the shim thing? Is it something any garage could (and ould know how to) do?

its basicaly a spacer that goes between the diff bearing and the gearbox case. You need a digital vernier to measure the ditances accurately but it easy enough to do. There's instructions on how to measure it in e-learn.

would you have to do this if fitting a std diff? sorry for the n00b questions.

Think so yes, its not a major issue, I think people have fitted them with the original shim having not measured anything and not had any problems.

cool mate thanks. if I ever get my clutch replaced I might throw a Q2 in

Hi All,

I am having a really hard time trying to resist a Q2 diff in my GTA...

So, theoretically speaking, if one would throw in a Q2 diff, what other work should you also do while having everything disassembled?

* New clutch? My car has covered 45000 km, would it be worthwile to fit a new clutch or is there so much life left in the original clutch that it is not worth the change? Should one perhaps fit a sports clutch of some sort?

*New front anti-roll bar? Would labor for this be decreased by the Q2 fitting?

* Other suggestions?

PS: The guy Peter K mentioned here:

Originally Posted by Peter K

I sold my Q2 to a Swedish Alfisti who needed it more then I did.. His original Diff was gone..(156 Sele)

had the Q2 diff mounted to his 156 GTA Sele end of last week and yesterday. I spoke to the garage doing the job (an Alfa/Maserati workshop in Helsingborg) last Thursday and they had begun the job then. He is probably out warming up the diff as we speak . I will ask him what he thinks about it, or maybe you know Peter?

by the end of the week I will be getting mine...hopefuly next week it will be installed on the car.

You don't really need an uprated clutch unless you are doing fairly serious mods, at least replacing it though sounds like a good move.
I posted a thread on the AD group N clutch impressions a good while back, but possibly overkill for your needs.

About the ARB I posted a link yesterday asking the same question about if it was worthwhile to fit a new front ARB at the same time as fitting a Q2, and the answer was a resounding yes (confirmed with the garage).

Any limited slip diff will transform the GTA - go for it!

Thre is a cool video of a 3.0v6 Q2 diffed car at the ring follwoing Guezen, if you need further convincing (and its very convincing )

Cheers,
TB

Originally Posted by Pax

Hi All,

I am having a really hard time trying to resist a Q2 diff in my GTA...

So, theoretically speaking, if one would throw in a Q2 diff, what other work should you also do while having everything disassembled?

* New clutch? My car has covered 45000 km, would it be worthwile to fit a new clutch or is there so much life left in the original clutch that it is not worth the change? Should one perhaps fit a sports clutch of some sort?

*New front anti-roll bar? Would labor for this be decreased by the Q2 fitting?

* Other suggestions?

PS: The guy Peter K mentioned here:



had the Q2 diff mounted to his 156 GTA Sele end of last week and yesterday. I spoke to the garage doing the job (an Alfa/Maserati workshop in Helsingborg) last Thursday and they had begun the job then. He is probably out warming up the diff as we speak . I will ask him what he thinks about it, or maybe you know Peter?

Originally Posted by Trailbraker

You don't really need an uprated clutch unless you are doing fairly serious mods, at least replacing it though sounds like a good move.
I posted a thread on the AD group N clutch impressions a good while back, but possibly overkill for your needs.

About the ARB I posted a link yesterday asking the same question about if it was worthwhile to fit a new front ARB at the same time as fitting a Q2, and the answer was a resounding yes (confirmed with the garage).

Any limited slip diff will transform the GTA - go for it!

Thre is a cool video of a 3.0v6 Q2 diffed car at the ring follwoing Guezen, if you need further convincing (and its very convincing )

Cheers,
TB

I'm still waiting for it to rain!!!! Don't think a diff is strictly necessary in a GTA in the dry - I've got a 2.5 box in mine still and whilst it rips through 1st quicker than you can squeeze it on, 2nd gear seems fine. My bro's 147GTA certainly doesn't feel like it needs one, in the dry at least, but then I didn't floor it in 1st - he's not had it a week yet and I was being gentle with it.

Sooo to sum up, I don't know what I'm talking about because I haven't driven it in the rain yet.

Im pretty sure the diff is a seperate unit and can be done without the gearbox being removed, so you dont need to wait until a clutch needs doing (although at 45k km's it cant have much left?)

Originally Posted by Pax

PS: The guy Peter K mentioned here:



had the Q2 diff mounted to his 156 GTA Sele end of last week and yesterday. I spoke to the garage doing the job (an Alfa/Maserati workshop in Helsingborg) last Thursday and they had begun the job then. He is probably out warming up the diff as we speak . I will ask him what he thinks about it, or maybe you know Peter?

AFAIK, Johan will get his car tomorrow. The diff went in last week without any problems, but they still had to do some other work on his car. I am still unsure how much of the Fitting kit they had to use to fit it. To be sure he had all, Johan bought the complete fitting kit.

I have heard some don't need to use the longer bolts (12 of them) and a few of the bearings/shims, so to minimize costs you might want to try and find out exactly which parts was needed, and which was not.

BTW i just ordered a replacement Q2..
Got a feeling the current price wont last long!

Straight line, the GTA is fine in the dry as standard for the most part on even roads. Under heavy cornering in 2nd its very easy to spin the inside wheel if you are pulling some g's though.
Its harder to spin the wheel in 3rd on the road under cornering, but you do feel the car pushing wide more in long corners with the open diff, whereas an LSD helps keep your line nice and tight - you feel sort of pulled into the apex rather than pushed wide of it.

As standard the GTA also torque steers on uneven surfaces with full throttle in 3rd, crossing the dividing brow of the road while overtaking can cause some tugging!

Originally Posted by Chris155

I'm still waiting for it to rain!!!! Don't think a diff is strictly necessary in a GTA in the dry - I've got a 2.5 box in mine still and whilst it rips through 1st quicker than you can squeeze it on, 2nd gear seems fine. My bro's 147GTA certainly doesn't feel like it needs one, in the dry at least, but then I didn't floor it in 1st - he's not had it a week yet and I was being gentle with it.

Sooo to sum up, I don't know what I'm talking about because I haven't driven it in the rain yet.

My Q2 diff just arrived
BTW EB spares shipped very quickly

It will be interesting to hear your thoughts on it having driven a plate diff and the Quaife diff.

Originally Posted by Trailbraker

You don't really need an uprated clutch unless you are doing fairly serious mods, at least replacing it though sounds like a good move.
I posted a thread on the AD group N clutch impressions a good while back, but possibly overkill for your needs.

About the ARB I posted a link yesterday asking the same question about if it was worthwhile to fit a new front ARB at the same time as fitting a Q2, and the answer was a resounding yes (confirmed with the garage).

Yeah maybe one should go for a std clutch. Problem is to know how worn it is. If I can use it for another 45000 km then it feels a bit premature to change it. This Q2 operation will add up to a neat sum of money anyway... Hey, it is time to put my boss up against a wall and demand that raise. Hell, if I explain this Q2 stuff to him I am sure he will understand...

...Ehrm, anyway, on the issue of front ARB, since I have the KW V3 coilovers fitted, the car is quite stiff already, so fitting a heavier after-market ARB in the front would probably be too much. To me it seems wiser to go for upper + lower strut braces (I have no today) to keep suspension geometry under better control. But the std ARB wears you say, so just to throw in a new std ARB is the thing to do?

Originally Posted by Chris155

Don't think a diff is strictly necessary in a GTA in the dry ... My bro's 147GTA certainly doesn't feel like it needs one, in the dry at least, but then I didn't floor it in 1st - he's not had it a week yet and I was being gentle with it

With coilovers fitted the inner wheel spinning issue has been a lot bettered, but like TB says it is still no problems to get the inner wheel to spin in 2nd gear when cornering hard and accelerating out. So a diff will probably be nice.

Originally Posted by Peter K

I have heard some don't need to use the longer bolts (12 of them) and a few of the bearings/shims, so to minimize costs you might want to try and find out exactly which parts was needed, and which was not.

I will most probably use the same garage as Johan, so hopefully they will know every detail since they have done Johan's car already. Very nice for me to have Johan as a lab rat

Originally Posted by Trailbraker

As standard the GTA also torque steers on uneven surfaces with full throttle in 3rd, crossing the dividing brow of the road while overtaking can cause some tugging!

This is very interesting for me since I do a lot of this kind of driving, and yes the torque steer in these conditions can be a bit annoying at times. How will the Q2 diff affect this kind of torque steer?

Yup, I'll have had a chance to try the lot on track - Autodelta clutch type in my car previously, Quaife ATB in bmofferals lovely GTA, and the Q2 diff making its debut for me at the Ring!

Comparing telemetry for the Q2, and AD diffs in my car will be interesting.

Originally Posted by sandys

It will be interesting to hear your thoughts on it having driven a plate diff and the Quaife diff.

Good to hear things are moving in the right direction TB.

Originally Posted by Trailbraker

I was impressed with a recently posted video by Guezen of a certain 3.0V6 156 with a Q2 diff at the ring.
TB

Hi TB,
Any chance you could link to that video, I`d love to watch it but it seems to be buried in some very long threads and the forum search engine leaves a little to be desired.

Cheers