Monster stoppers

[stephendell]

They fit!!

But will they work



Anyone want a pair of nearly new ATE grooved power disks with just a few hundred miles on them

Be careful you don't flip over Stephen

They look like heavy monsters.

[stephendell]

I must try and weigh a complete set to compare with the OE set up.

While fitting I noticed that the calipers are much lighter than the originals as they are all aluminium.

However the rotors must be fairly heavy although the centre bell is also aluminum.

Me thinks it could be too much at the front....have you done anything to improve the rears?

[stephendell]

Exactly the same, but with handbrake mechanism.

Going to check progress this morning

You can never have too much

I see what you've been doing after I took you for lunch, must have been hard work with all that pizza inside you! They maybe a bit ott for a standard car but with 300 bhp + of supercharged 3 litre 24 valve they will be necessary I'm sure. Will look fantastic with the Alpine engraved calipers. The best thing is it gets rid of the standard single pot calipers which are expensive and seriously shite. Having such a large braking area should mean you'll have excellent ability to control your rate of decelleration

Road tests of the time usually praised the standard GTA brakes. Describing them as 'superb' or 'immensely reassuring', Autocar desribing them as having a stopping power well in excess of 1g. That's good even by todays standards isn't it?

That said, there's no harm in having even better brakes!

[stephendell]

They were OK in '86 but a bit weedy by todays standards. You get bigger brakes on a Clio these days. OK for standard output though.You have to remember that the A610 had 300mm as standard by '92, much larger than the GTA for only 50BHP extra (and a bit more weight).

The biggest limiting factor back in the 80's was the wheel and tyre sizes, although ford managed 4 pots on the cosworth as standard. If they made the GTA today it would have seriously more power and seriously bigger stoppers.

1g is average these days. 0.9g for an typical saloon. A decent sports saloon can max out at 1.5g (BMW etc). A Radical can pull around 1.7g in circuit testing. F1 cars are 2.5g+

(1g is the total braking force needed to equal the weight of the car).

However Lee's picture probably isn't too far from the truth at the moment. Definately expect some nose dives. Will be treading carefully (literally!) until the rears are fitted.

It really just depends on how fast you want to go. To go round a track quickly you need to able to stop quickly and reliably. I guess the new brakes will only need to work at 50% of capacity to have the same stopping power as standard brakes at 100%. So less heat and less fading.

Also means you don't have to start panicking quite so early at the end of the Bruntingthorpe runway!

Having said that, one of my reasons for this starting this (lengthy!) project was far more simple... there was simply no way I was going to pay £765 for a pair of replacement standard rear calipers!!

Yes, I do agree with all your points. They must have been very good in thier day, which makes them still respectable today, but still can be much improved by todays standards. And even if actual braking performance wasn't improved (which I'm sure it is), improved resistance to fade is probably even more important, especially for track work.

What about pedal feel and being able to modulate your braking force accurately? I imagine this is better too?

[stephendell]

Rear brakes in development on Tony Smith's rear axle.

Sorry about the bad quality. I took these on my phone!

Will the standard master cylinder be able to cope with the extra fluid capacity of the calipers I wonder?

[stephendell]

I hope so, I was worried about that but apparently most other cars are OK, but then most of them don't have such crappy calipers to start with.

The 'theory' is that although the piston area is much larger, the piston travel is much less on the 4 pots than the big single pot sliding calipers (which are effectively pulling and pushing), so overall it evens out.

Will have to wait & see to be sure! Otherwise it'll be a new master cylinder too.

[stephendell]

Well I took my life in my own hands and went for a test drive.

Very cautiously initially!!

Initial impressions. Pedal was firm. Less travel than before. Nothing un-toward, no pulls to one side, nose dives or any strange behaviour. Balance seemed fine. Nothing catching or rubbing.

Will try a higher speed run tomorrow!

What about pedal feel and being able to modulate your braking force accurately? I imagine this is better too?

Very good. Pedal is firm and feels more direct.

Will the standard master cylinder be able to cope with the extra fluid capacity of the calipers I wonder?

Yes, no problem, pedal travel is less if anything, so hopefully enough capacity for the rears too