Are bigger brakes always better

thexav

Pro Tuner
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2002 Clio 172
Sorry lots of brake questions.

Is it true that the bigger your brake discs the better your braking will be?

Surely the grip you get from you tyres is the limiting factor here, and there must be a point when larger discs cease to give any benefit?

Are vented and grooved discs much better than solid discs of the same size?

Do you need to go to 4 or 5 pot calipers to improve braking?
 
Vented & grooved allow better heat dissipation = a good thing.

Going from my experience of Scoobies....
Bigger is better. The stock brakes on my MY98 are shockingly bad.
When money allows they will be upgraded with larger disks and will move from 2 to 4 pot calipers.
At the moment I've had the lines replaced with braided hose and better pads put on. That alone was an improvement.
 
Sorry lots of brake questions.

Is it true that the bigger your brake discs the better your braking will be?

Surely the grip you get from you tyres is the limiting factor here, and there must be a point when larger discs cease to give any benefit?

Are vented and grooved discs much better than solid discs of the same size?

Do you need to go to 4 or 5 pot calipers to improve braking?

I will answer your queries in order

Yes larger diameter will reduce stopping distances using the same calipers. they will delay the onset of fade due to their ability to absorb more heat.

Tyres are the limiting factor BUT tyres with a lower TW will grip the road more and reduce stopping distances but wear faster that ones with a higher TW rating.

Undoubtedly as they will dissipate better.

Not necessarily as higher quality pads can help in some situations like towing where they will handle heat longer than stock pads before fading BUT more pistons in a caliper are definately better than single piston sliding calipers.
 
Sorry lots of brake questions.

Is it true that the bigger your brake discs the better your braking will be?

Surely the grip you get from you tyres is the limiting factor here, and there must be a point when larger discs cease to give any benefit?

Are vented and grooved discs much better than solid discs of the same size?

Do you need to go to 4 or 5 pot calipers to improve braking?
You're right that tires become a limiting factor, but most performance enthusiasts put wider tires on as well. When I had a '94 Corvette, I upgraded the wheels to wider wheels and larger diameter. That allowed me to put on larger brake disks and calipers.
I'm not sure about the benefit of more pistons in the calipers. I think going from 1 piston to 2 (in a floating caliper, or from 2-4 in a fixed caliper)) is beneficial because it spreads out the clamping force more evenly, but the added expense of going beyond that is only worthwhile for race cars.
Tell us about your application, and we can have a better discussion.
Thanks!
Paul
 
Sorry It's a Renault Clio 172, with a fast road cam an induction kit and piggyback ECU. On the Dyno I'm getting 197bhp at peak, so not massive and it's not that heavy a car.
 
Your Clio is app 250 kg lighter than my Type R and I enter sprint events on closed roads as well as a couple of track days so I fitted a front BBK upgrade with 4 pot AP Racing calipers plus 30mm larger 2 piece slotted discs that were app 3+ kg's lighter and love the way they work every time when braking as late as possible at events.

They are compatible with all the cars built in electronics liks ABS ,EBD , ESCand the pedal height and feel is not altered.
 
If the car doesn't have much grip then it wont stop the car much quicker, a brake is just converting kinetic energy to heat. Larger disks provide better stopping over repeated applications.

They also give more stopping control and better feel.

So for general use go with 20-40mm bigger disks, I agree with @helphos so don't worry about extra Pistons too much or you'll need to get the server uprated the Clio 172 servos should be just fine. Choose some good pads and a vented/grooved disk and you'll get on just fine and appreciate the extra stopping power.
 
As I stated my BBK works perfectly with all the factory electronics and the factory servo / booster.

The reason being is that the piston fluid volume of the 4 pots is the same as the much larger single piston sliding caliper so the pedal height and feel remains the same in my experience .

BUT in my old car when I had a BBK upgrade using Nissan / Sumitomo 4 piston calipers they had to bore and sleeve the master cylinder to increase the bore size in my car so it displaced the same volume of fluid as the donor cars master to get the pedal height close to stock and I entered that car in countless events over the 20 odd years I owned it with zero problems.

You can use larger diameter discs but the factory caliper will need a mod to relocate it further out to suit and that will improve the retardation due to the lever principle , the longer lever is the same as the pads being further out on larger diameter discs.

I hope that helps explain things ? :)
 
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