Brake upgrade solutions

I really need a brake upgrade and I have a few questions...
I have 15" wheels on my X
For the front:
Can I use the 305mm Coupe turbo discs with the brembo calipers(with adapters, of course) with these wheels? If not, can I machine down the discs to a lower diameter or use the brembo calipers with 284mm discs?
For the back:
Can I use the Uno Turbo discs and calipers or I can even hope to use Bravo/Brava/Punto GT 257mm discs adn calipers? Is It true that the X`s standard front discs/calipers are a straight swap with the back ones?

Thanks in advance, any information would be apreciated.

The question I have to ask is what do you want to achieve?

But lets answer some of your questions first:
The rear brakes are essentially the same as the front as standard, the discs can be swapped but that is it - the calipers are different and the pads thinner.

There isn't much you can straight swap to the back of the car, the best you can hope for in terms of an upgrade without spending big money is a decent set of discs and high performance pads. If you can find them 132 rear calipers are an old favourite for this but they are rather hard to find.

The front is a slightly different matter. Mk1 Uno Turbo (non-abs) calipers are an easy swap and allow you to adopt vented discs without messing up the pedal ratio. The trick in all this is that you need the mounting frame from the Uno too. Once you have this you can use a larger diameter disc with a suitable fitting kit. Sadly the Mk1 Uno option is also becoming exceedingly hard to find as while the calipers are easy enough to get the mounting frames are not.

If you are just looking to make the brakes look bigger then this is about the easiest way to do, everything else requires custom fabrication of some kind.

If you are looking to increase braking capability then you don't *have* to increase the size of the discs - it may even work against you if you go for a completely different caliper as the front-rear bias will be out and the pedal ratio as well.

A good cleanup and service of the original calipers with new discs (Tarox Sport Japan are the best I tried) with a moderate fast road pad (avoid full competition pads like the plague), you'll need externally braided brake hoses and good clean high performance brake fluid. The original mounting frames for the calipers need regular cleaning but other than that the whole original setup is actually very good. 99% of problems stem from poor maintentance rather than bad design.

If you want the car to stop quicker then I suggest you look at tyres and suspension geometry rather than brakes.

Some further thoughts on the subject (it was getting a bit late last night when I posted)

The coupe discs should fit - in fact any 4-bolt hub based disc from the fiat range will "fit" but the offset of the disc from the hub face could be an issue (not something I've ever tried). They all use the same PCD and spigot size to the best of my knowledge.

You should never machine a brake disc unless you really know what you are doing and this includes machining the face of the disc where "high points" develop. If the disc is showing that kind of development it is time to get a new disc.

If the disc doesn't fit then find a different one!

You can use a caliper with a range of different disc diameters, the limiting factor is whether or not the disc will allow the pads to sit cleanly on the face without risking contact with the spine of the caliper. If you go to Brembo's (or any other performance brake manufacturer) website and look up their aftermarket calipers you should find that they fit a range of disc sizes and you should be able to deduce what the limitations would be.

You can fit the 4 pot brembos from a coupe to an x, it's alot of work though.

To start you need at least a 16inch wheels using the 305mm discs remebering that due to the design of the brembo caliper it's hard to get after market wheels to fit the coupe let alone an X1/9, a after market pedal box with bias adjuster.

There's more to it but, as jimbro said you get problems with offset etc, it's a head ache but can be done. Mine has the coupe's brembos front and rear.

Some pics, excuse the quality, dodgy camera phone.

Another cheap and effective upgrade is to use the vented front discs and calipers from a tempra estate (Turbo diesel model). They are essentially the same as the uno turbo but these are much easier and cheaper to find than the uno turbo set up.
A general word of caution though, although they look very similar they to the UT they are (from experience) slightly larger and require at least a 14" wheel and preferably a 15" depending on offset. They definately foul on the std 13" wheels when UT ones fit unaltered.
As for the rear, Alternative Autos supply new Fiat 132 rear calipers at reasonable costs. Straight swop.
The combo of 132 rears and UT or tempra fronts with braided hoses give excellent pedal feel and have never caused me to think that there was a bias problem, i.e. no lock up on the fronts.

Even the UT brakes do not fit *all* 13" rims - a 14" rim is the basic starting point for this sort of thing.

The front end lockups that the X1/9 is commonly known for have never been about the brake setup itself and an awful lot to do with negligence.

The lockups (keeping in mind that *all* cars of that period would lockup the front wheels to a degree) were largely the result of poor maintenance.

The tyres have to be in good condition, the discs have to be in good condition, the suspension geometry has to be correct, the brake mountings have to be clean and the calipers have to be in good order.

Most owners of these cars were not using them everyday and as a result the cars were left standing for extended periods (even if it was in the dry). The discs become pitted resulting in brake grab, the mountings become pitted resulting in the calipers failing to work in a smooth manner, the calipers themselves would start to become sticking resulting in sudden application of brake pressure instead of the smooth application the driver thought was being used, the tyres were frequently sub-standard (budget replacements or originals left on the car for too long) and the suspension geometry was often left unchecked and it is absolutely critical on an X1/9. The end result is that while the brakes still worked they did not work as well as expected.

Later designs of the brake calipers (eg Uno Turbo) removed some of the problem by correcting the need for regular use and maintenance but the brake design was a good 15 years later which is a good enough reason for swapping over to them regardless of any other benefits. Similarly brake pad materials have come a long way since the early 70s as have tyres, just using modern manufacturing removes a lot of the problems.

I use a Tarox setup on my car borrowed from a design used by Porsche and Ferrari (you can imagine what the cost of pads is like) but it all fits inside a 13" rim.

Hi Fett,

Very mean looking car, those arches look stuffed to limit. I am planning the exact same Brembo conversion on my X1/9, but have a bit more scope with wheels as it has a Eurosport body. Looks like you used a wheel spacer to get your caliper clearance. Can you tell me what thickness spacer, wheel offset/et you used and what size tyres you are running on the front?

I did a prelim fit up this weekend, and it looks like the Brembos will fit with just a tiny bit of clearance grinding to the ears on the hub carrier, and a simple flat plate dog-bone shape adapter. Is this what you found?

I PM'd you too, btw - sorry to be a pest!

Cheers

Rachael