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Discussion Starter #1
I have a little homebuilt with 105 2L front brakes and 4 cyl transaxle discs at the rear.
The car runs a slightly modified 2L and weighs about 850kg.
I do a bit of club racing, just hillclimbing at the moment but would like to do some time trial circuit stuff as well.

The problem is that it is time spend some money on the brakes. The discs are worn (now less than 10mm :eek:) and the pads need replacing.

Would just new front discs and good quality pads (preferably ones that don't produce so much black dust) be good enough or should I upgrade to say BMW 4 pot calipers? Or maybe just bite the bullet and go to ventilated front discs.

I know that only I can this question but still I'm be interested hear what the brains trust thinks.
 

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At only 850kg, I would think you would be fine with stock calipers and discs in good condition. Get a good dual-purpose pad and you are good to go. The stock components will stop you quite well, but they are quite heavy. A set of aluminum calipers like the Outlaws Murray mentioned will cut a lot of unsprung weight, if that is of interest to you.

Erik
 

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Discussion Starter #4
Thanx so far.
No I'm not all that interested in unsprung weight, well not enough to spend a fortune to achieve a minimal result. This type of car usually comes with a solid I beam axle so I'm well ahead of the game in that regard.
This is just a fun car that I like to drive fast but I do like to be able to stop fast too, and repeatably.

I am wondering if Monty discs with BMW calipers would be a good combo.
The dimensions appear about the same except the height which is 10mm less. Nothing a spacer can't fix.
Here is the DBA catalogue
http://www.dba.com.au/2006/catalogue_aust.asp
The 2L Berlina is listed as 358 while the Montreal is 2360.
Surely some alfisti has tried this.
 

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Brett, I previously had Montreal vented discs and Coleman aluminum calipers on my race car. I went back to solid discs after pricing replacement Montreal discs. In my opinion, they are just overkill for our lighter cars.

Erik
 

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Brett,

I have to agree with Erik on this one. If it is stopping power you are after there are pad compounds out there that will simply amaze you with the increased stopping power. Carbotech's 10 compound has a coefficient of friction (cof) of .62, Raybestos ST43 is .67, Porterfield R4s is .54. I think "sport" pads are typically in the .3x range. You can find pads over .7x but typically need downforce like a formula car to not lock them.
The different compounds have different attributes such as noise, dust, disc wear but then you can simply switch to a street pad if any of those become annoying.
Bottom line is a better pad and race quality brake fluid (Motul 600, ATE blue, srf etc) will give you instant performance. When that is not enough, then start saving for vented rotors and/or aluminum calipers along with the race oriented pads and fluid.
 

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Let me also second this,

Lots of Alfa owners like to use aftermarket calipers and rotors and, with respect for what individuals want, I suspect some of these changes are merely for appearance. A stock setup with good rotors, calipers, fresh high quality brake fluid, and some of the new technology pads, will produce very good results. Further, this is much cheaper than some of the alternatives.


Brett,

I have to agree with Erik on this one. If it is stopping power you are after there are pad compounds out there that will simply amaze you with the increased stopping power. Carbotech's 10 compound has a coefficient of friction (cof) of .62, Raybestos ST43 is .67, Porterfield R4s is .54. I think "sport" pads are typically in the .3x range. You can find pads over .7x but typically need downforce like a formula car to not lock them.
The different compounds have different attributes such as noise, dust, disc wear but then you can simply switch to a street pad if any of those become annoying.
Bottom line is a better pad and race quality brake fluid (Motul 600, ATE blue, srf etc) will give you instant performance. When that is not enough, then start saving for vented rotors and/or aluminum calipers along with the race oriented pads and fluid.
 

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Yes they are right, you don't need to go to the extent for your Alfa that I did with mine.

I didn't pay attention to how light your car is and that your overseas so Performatek is not realy a good option for you...........................just plain didn't think out your post.

I was thinking about the heavier Alfa's and especially the ones with high output engines with those cars increasing the braking power to a four piston caliper is not overkill. Most modern day cars are running with vented rotors and four pistons calipers up front, vented rotors in the rear and those are street cars. Even my little VW Bug has them and it's pretty close in weight to my S-4 Spider.
 

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Discussion Starter #9 (Edited)
Thanx guys, your wisdom has inspired me to go out and get some of my own.

Thinking about it I reckon I've got it all A--about.
Fact is I have a mismatch of brakes, 2L Giulia up front and Alfetta out back.
Comparing a stock Alfetta's front brakes to a Giulia, the Giulia's are noticeably bigger - the pads are nearly twice the area.

My theory is, that due to it's extra weight over the rear axle, the Alfetta was a completely different balanced car and thus required smaller front brakes than the more nose heavy Giulia.

Now, not only do I have this mismatch between differently balanced cars but I have gone and made the situation worse by placing the front axle line several inches ahead of the engine. And the to top this off, 30% bigger rubber at the rear (for looks only).

More effective front brakes may only result front wheel lockups (which I must admit does already happen sometimes under panic braking), so what I probably really need is bigger rear brakes.

A smaller master cylinder may help somewhat but I would still be stuck with this poor balance.

The car does pull up quite quickly and very flat (nervous passengers do often remark on this) but it does suffer a bit of fade after a few heavy stops. Maybe just new front discs and decent pads all round combined with an air scoop to direct cool air onto the front discs is all I need.

Thanx again for the advice and please feel free to correct any of my thinking.
 

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Discussion Starter #11
Thanx Scott,

As far as I know proportioning valves are mainly fitted to the rear brakes in order to reduce rear lockup during hard braking. I have the opposite problem of the front brakes locking first. Its not all that bad and certainly not dangerous but now that I am wiser (thanks to you guys :)) my concern is that more efficient front brakes may only make this worse.

I could install an adjustable proportioning valve on the front but that seems counter intuitive to me.

At the moment I do have the standard non adjustable Alfetta rear proportioning valve fitted and I will ditch this in favour of either none at all or an adjustable one. The latter seems a better choice to me because with that and the right front/rear pad selection I should be able to get it just about right.
 

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Similar problem that rear engine cars have. In one of these kind of cars you cant jump on the brakes untill you get the nose to come down to get the load onto the tires. They usualy have more compliant springs in the front. You might go with a racing setup with two master cylinders where the link between the two is adjustable.

Do you have any pictures? Sounds cool.
 

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Discussion Starter #13
Tom, if were building the car today that's probably the way I'd go.
But she's essentially just an Alfetta with a bit better weight distribution and more efficient front brakes. The current setup works fine, just needs a bit of tuning.

Here's a little vid of her struggling up a hill.
 
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