Just needs a guinea pig to find out!

Having driven with both (but not in the same car :)) , i think the biggest difference in a quaffe diff over a viscous diff is much less wheelspin when cornering as with the viscous diff you always have this slippery feeling every time you apply throttle and the turbo comes in. The quaiffe can split the power much better than a visco and also allows you to throttle earlier when entering the turn wich makes it kinda easier i feel.

Assuming the usual bit of sharing goes on between Fiat and Alfa you could try the Q2 diff works quite well in mine and less than £250 from Alfa

Its one of these

This works in the V6 and JTD as they have the same gearbox, from what I recall the Coupe also used an Alfa box (perhaps only the six speed?)

As to whether it would provide much greater benefit than a viscodrive I couldn't say, perhaps just a bit more immediacy to its response.

Not so much a case that the Coupe uses an Alfa box (they don't), but the Alfa 6 speed internals fit (and work!) inside the Fiat 6 speed casing

Of course Quaife do list an ATB diff for the Fiat Coupe on their website.

http://www.quaife.co.uk/Fiat-Coupe-Quaife-ATB-Differential

Not cheap though

Why did you have to do that now? Not that expensive really for what it is especially if it is a direct fit. Something for the future i feel.

aaaagghhh mmuust resist...

So they do, and quite frankly that's cheap, paid nearly £700 for mine - see the Alfa 156 V6 fitment. But as its the same diff they list for Alfa 147 I would suspect its for 16vt Coupe?

Mind you its listed as fitment for half the Fiat range including Grande Punto and Doblo so anyone's guess

I've been thinking of fiddling with the differentials a bit. I have a track day Bravo HGT. For the track it would benefit from shorter gearing. As far as I've figured out the shortest gearing would be in a 147 1,6 liter Alfa. Am I right that the differential fits? Could I change the whole gearbox, or does it require some parts mixing to get it done?

This post is nearly 8 years old lol.

Has the information changed a lot in 8 years?

Just thought I'd rather bump up an old thread close to the issue rather than start another one on the same matter.

Do you have any valuable input?

No I don't!

Plenty of info on diffs for the Coupe - just do a search for "quaife"

As for gearing - probably easier to use lower profile tyres....

So far I've managed without a Quaife. Afterall a good suspension setup with an NA engine has been ok without a Quaife.

I only use 15" rims and the common tires are around 195/50 or 205/50. Smaller rims won't fit and thinner tires are hard to come by. I mostly buy used tires from competitive racers, so the size choices are limited by regulations.

Most of the time I'm on third, some slow corners on second, and the fourth gear only on the main straights. On second I suffer somewhat from wheelspin and the gear runs out very fast. With a lower third, I could use that, fourth and even fifth.

I'm also upgrading the engine from 2,0 to 2,4, so the extra torque will help. That is why I feel that I could certainly benefit from shorter gearing. Afterall its just a track day toy, so top speed is irrelevant.

Edit: here you see the track: Youtube

There is a cool down lap at the beginning. The fast one was 1:42.7 driven at my friends bachelor party. My record stands now at 1:38.55