A slightly unusual one, I need to fit 15" rims to my 20VT race car to met the regs for the race series I'm entering.
has anyone fitted 15"? The calipers look like being the biggest problem to me.

15" rims definatley won't go over the brembos on the front. The only way you'll be able to do it, is to fit smaller callipers. The 20v N/A callipers work quite well, with decent disks, pads and fluid etc... But you have a good bit more weight in a 20vt, so I wouldn't recommend it, especially on a track.

Or depending on how much your willing to part with, you could always go after market? Tarox or something but brand new the conversion won't be cheap. 1k + at least.

Looking at options for radially mounted calipers at the moment, not to worried about discs, I can machine down the existing new disks I have to fit.

I might be able to get some Seat Cupra radial calipers to fit it, maybe.......

What race series is it? Seems unusual to force smaller than standard wheels.

ITCC, Irish Touring cars, only two tyre sizes available for my class, 15" and 17", 17" wheels are a waste of time considering the efforts we are going to in adjusting the gearing to suit the track. The car should be topping out at 130mph

Go 17 inch. With a low profile tyre you should be able to get under the stock 20vt effective rolling circumference. It's gotta be better than compromising your brakes.

195 / 50 R15
215 / 45 R17

The above are the only two sizes of Yokohama A048 tyres allowed in the class, the 17" option rolling circumference is quite a bit more than the 15". It makes a massive difference under acceleration!

I'd put 14" wheels on it if i could!!

The Coupe 20VT is high geared, I can see how the acceleration could be improved with lower gearing, for a twisty track.

Exactly, and they don't get more twisty than Mondello Park in Ireland! even the fastest cars will never see any more than 110mph on the main straight

Just picked up a set of Radially mounted rear calipers off a Boxster, now to make them fit!

You didn't mention you had no choice in tyre.

Is there any specific advantage in radially mounted calipers? Looking at some they would take up more space than standard mountings. I don't know specifically what the Boxster ones are like, presumably the main thing you want is low profile around the disc so the smaller wheel will fit.

Have you thought of the kits sold by Demon Tweeks (amongst others) - http://www.demon-tweeks.co.uk/performance/brake-kits/car/fiat/coupe/1998/2-0-20v

Silly class, I wouldn't attend.

It's easier to make them fit on a car with limited space like the coupe, cut the old lug mountings off and the radial mounts are a bit lighter, also an advantage if I ever want to fit larger discs as they just need to have spacers fitted.

Those upgrade kits are very nice, but silly money, the Porsche calipers cost £250, and we will machine the existing discs to fit, The same outcome for a quarter of the cost

Why is it silly?

15" speedlines fit over brembos.
Popular with the Peugeot croud ,need wobbly bolts.

Sorry, I meant the regulations.. With a Coupe I'd choose another class instead of strangling the car to fit. Just my immidiate silly response.

Which model wheels and what size disc?

LiamM, you'll have to start a project thread. Looks like your build will be a good one to follow.

Update, we've managed to fit 15" wheels from my 16V Coupe onto the yellow 20VT Race car, discs were machined down to fit, mounting points for the Calipers modified to allow some adjustment, and 30mm spacers with stud conversion to allow the rim clearance

Also, we've turned the coupe 5 speed 'box into an Alfa / Fiat hybrid short ratio 6 speed!

Ingredients:

1 no spare Coupe 5 speed 'box
1 no spare Alfa 2.5V6 6 speed 'box
1 no Engineer with the patience of a saint

Method:

Empty the contents of the 2 boxes into a large pre oiled bowl and stir vigorously.
Use the engineer to fit the 1-5 gears from the coupe box and the 6th gear from the Alfa box, to the Alfa final drive, in the coupe bell housing, using the back end of the longer housing from the Alfa box to accommodate the longer final drive shaft.

Simple, easy and cheap mod, a spare V6 box can be got for a little as £50

Q2 differential should also fit, I'll be going to a 1.5 way plate diff when funds allow.

Liam great update - would be very interested if you manage to get the Q2 to fit!

Q2 is a direct fit, differentials are identical, both were on work bench last weekend

Are you sure its a direct fit. Other people who have fitted them say mods are required