Rear brake upgrade

[kaanage]

The red car with 312mm and brembo 4 pots, with 256mm vented rears certainly pulls more g's under brakes, when both running the same tyres and both on Remsa pads all round.

Odd. I could brake hard enough to get the ABS pulsing with the stock 256mm rotor setup on my car while driving with well and truly warmed up semi-slicks. Granted, I had to push the brake pedal fairly hard but there's no way the car was going to be able to pull more braking g's with stronger brakes. I updated to the 288mm GTi setup for the better heat absorption/dissipation reasons you stated since the stock setup would have the pedal going soft at certain tracks.

The only reason I can think of why your red car pulls more g's under brakes is that it is noticeably lighter than the silver one (I'm discounting the aerodynamic differences).

[seangti]

I compare the difference with mountain biking experience. I have two bikes, one with mechanical (cable) disk brakes, they other with hydraulic disc brakes, the bike with the hydraulic brake is less prone to lock, easier to modulate on the limit of braking to the bike with mechanical brakes. They'll both lock the wheels, but the control and modulation on that threshold is much greater, therefore allowing you to utilize the fractions of the grip available.

[kaanage]

Yes but that doesn't mean to larger (or hydraulic) brake setup is providing more final braking power due to traction limits being less than the brake themselves
It may be more controllable but then rotors and pads have a large influence on that as well.

[Blue9N3]

Bigger brakes are usually to reduce fade, to brake more consistently , not necessarily brake harder (although larger brakes would probably allow you to stop quicker from a very high speed, say 200++?)

More than likely, stock or larger brakes would stop in the same distance on the first stop from 100kph, but by the 10th stop, I know which one id want


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[louis19]

Bigger brakes are usually to reduce fade, to brake more consistently , not necessarily brake harder (although larger brakes would probably allow you to stop quicker from a very high speed, say 200++?)

More than likely, stock or larger brakes would stop in the same distance on the first stop from 100kph, but by the 10th stop, I know which one id want


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I can assure you my stock sized brakes don't compare to Gav or Seans bigger brake setups. I find the Remsa and DBA T2 rotor combo a good upgrade over the stock rotors and pads, but they simply can't stop the car anywhere near as quick as Gav or Seans regardless of if its the 1st or 10th time.

Also after driving Seans red devil on the weekend, there's a very clear difference in the amount of pressure needed to achieve the same braking power on our cars, even very evident driving around the block a couple times.

[h100vw]

The a1rms are another level of sharp now I bedded them in. Like hitting a wall.

[kaanage]

Bigger brakes are usually to reduce fade, to brake more consistently , not necessarily brake harder (although larger brakes would probably allow you to stop quicker from a very high speed, say 200++?)

The larger brakes will only stop you faster from very high speed if the brakes are getting so hot that they fade out during the braking period. The brakes would need to be truly undersized for this to happen.

More than likely, stock or larger brakes would stop in the same distance on the first stop from 100kph, but by the 10th stop, I know which one id want

While this is definitely true, if you are getting to this situation on public roads, then you need to reevaluate your driving technique. I have never been left behind on a cruise even when others have cooked their brakes on the same cruise.

Even on track, brakes are one of the least important components in achieving ultimate lap times - I got within a second of my best lap time at Sandown (which is very hard on the brakes) after air got into the system and the pedal was almost going to the floor. It's unnerving but as long as the brakes still work you don't actually go that much slower.

If you are RACING (as opposed to doing timed laps, happy laps, hill climbs), then braking becomes much more important for the TACTICAL advantage when passing or preventing a pass but as long as they don't fade right out, the effect on ultimate lap time is actually quite small since you just don't spend that much time braking.

I can assure you my stock sized brakes don't compare to Gav or Seans bigger brake setups. I find the Remsa and DBA T2 rotor combo a good upgrade over the stock rotors and pads, but they simply can't stop the car anywhere near as quick as Gav or Seans regardless of if its the 1st or 10th time.

If that's the case, then you either have tyres that are quite a step down from theirs or there is an issue with your brakes. While the Remsa's won't give the bite of more aggressive pads (once they are properly bedded in and warmed up), you should still be able to reach the limits of adhesion quite easily. I've used both on the track with my GTi front brakes and the Remsa's still pull the car up just as well but it takes more pedal pressure (and the pads show more wear).

The a1rms are another level of sharp now I bedded them in. Like hitting a wall.

Yes It's very noticeable how much harder they bite once bedded in properly with the multi crash stop procedure. The big problem I have found with them on road ('cos I drive for economy) is that without consistent hard driving, they will go green again after a while which chews out the rotors and squeals as well as not biting as hard.

[seangti]

I absolutely understand your position, it all comes down to the lowest common denominator, which is typically the tyre grip. The difference in lap times between my silver car and red car also supports your position that brakes don't save significant time on the track.

With all that said, when I'm coming into a hair pin at ~190kph with an apex speed of ~80kph, it's nice to know that when I go for the brakes, I'm going to have a pedal, it's hugely confidence inspiring. I guess it's about feel and confidence. There ability to slow you down immediately as you apply at that high speed is much greater than I've experienced on a small rotor, part of it is purely down to leverage too.

On a 288mm set-up with Remsa (not a track pad), I was exceeding their performance window. I couldn't put the car on it's nose on successive laps. On the 312mm with Remsa, they lasted and felt better, great when new, but were deteriorating in feel after track time, or particularly if I'd overcommitted to a corner, the pedal took half a lap to come back. The A1RM's are operating in their designed temperature window (at the lower end according to my rotor temps) and maintain feel for the drive home. Perhaps a track suitable pad on the 288's would be suitable, though you also can only get a DBA T2 rotor, not a T3... relevant or not I don't really know. I do get the occasional squeal with the A1RM's when cold, but feel is still fine.

Though we've probably hijacked the hell out of the OP's thread, sorry dude.

In short, IMO, it's a waste of money if you aren't utilizing the upgrade, or currently reaching limits of the factory set-up, which, with good fluid and pads, can be quite effective to run hard.

[sambb]

Unless fade is singularly your biggest problem I dont really see the point of having braking power way beyond what your tyres can handle or the point at which ABS will kick in. eg time attack cars pull up from F1 speeds on tiny little brakes. Fade avoidance over time is not their enemy but unecessarily high rotating weight and unsprung weight is. They certainly have the braking power to do it though even with relatively small brakes.
Why shell out for the lightest rims and then fill them with excess braking weight. Then you're still at square one in the unsprung weight department and end up with arguably more or less the same braking power especially if your on more streety track tyres.

[rgvlee]

I'm more thinking of doing it 'because I can'