ambystom01

iTrader: (7)

It's simple physics, increasing the size of the pads is irrelevant. The two factors are the force applied and the coefficient of friction between the pads and the rotors. The formula is

F=uN

Where F is the braking force, u is the coefficient of friction and N is the normal force or the hydraulic force. The size of the pads has nothing to do with it. As I said, the size of the pads is more to do with heat than anything else. Larger pads can cope with more heat before they're used up. For a single hard stop, the size is irrelevant.
For more information, read this thread. https://www.evolutionm.net/forums/09...-09-wrx-5.html
If you're only tracking the car occasionally, there's no point in spending big bucks on a serious brake upgrade like the Evo Brembos or an aftermarket BBK. Realistically, you won't be pushing the car hard enough to warrant it. If you tracked the car every weekend, it could make sense but even then, BBKs are more about heat than stopping distance. Race cars need big brakes because they're going 20, 30, 40 laps non-stop, the brakes don't have time to cool down. If you're just doing track days, you're unlikely to do this many laps in one session. Moreover, if you're doing that many laps, other things are likely to go wrong, like oil temperature or the transmission. I took part in track days this year with an Evo MR and he was only able to do maybe half a dozen laps before his transmission overheated. At that point, even on something like the Ralliart, the brakes wouldn't be an issue.
As I said before, unless you're driving like a real nutter, the stock brakes should be more than fine on the street. If you're driving so hard on the road that you need a racing setup, you have bigger problems (like the cops or the need for psych evaluation) than the brakes.
I believe Robispec looked into what was needed for the swap.

jcm308

So Amby you're saying that Bill's brakes didn't let him down during his track day (Remembering that ambient temps in Aus are generally higher than the USA)?

So if that many things are needed then how do we have the same drivetrain setup as the Evo9? As I mentioned a few posts ago, I was under the assumption that ours was more like the X.

ambystom01

iTrader: (7)

Since I don't know who Bill is or what his symptoms were, I have no idea. You're discounting the fact that brakes are made up of several parts. I suspect if he had an issue, it was due to the pads and the fluid, not the calipers or the rotors.
Drivetrain is separate from the brakes. Keep in mind as well that when they say drivetrain, they mean differential. The transmission is new, the front differential may be new as well (if it's contained within the transmission itself) so really the only shared piece may be the rear differential.

jcm308

But the X MR has the same G'box.

(Bill is the guy that did post#7) He mentioned in his post that he had upgraded pads and rotors. Judging off what other things he's done to the car I would assume that fluid was also done. The only thing that I wouldn't be sure of is if he did lines (which do also contribute to operation and fade).

ambystom01

iTrader: (7)

The X MR has a similar transmission but it's not completely identical. The top gears (5 and 6) are different and there's some suggestion that other parts may be as well but it's not clear, it could just be a tune issue. the transmission is also but one part of the drivetrain and the drivetrain has no real effect on things like the brakes, they're separate pieces.
Saying he upgraded the pads isn't enough information. That could mean he went to a better street pad, which won't hold up to track abuse, or he went to a mild track pad, that didn't hold up, or he went to an extreme track pad, who knows. There's a vast difference from compound to compound. I would be absolutely amazed if he ran a true track pad (Hawk HP+, Ferodo DS2500/3000, etc) and still had issues. I ran Hawk HP+ pads, and tracked the crap out of my car, without issues, as did some friends of mine with STIs.

jcm308

I had DS2500's on my previous car with rotor, fluid and line upgrades. At the track it was ok for a few sessions but after that I got fade and ended up stuffing my rotors by the end of the day. Don't want the same thing to happen to the RA.

The drivetrain includes the diffs, axels, hubs, tailshaft etc. I'd find it hard to beleive that MMC would develop 2 completely seperate sets of these for the 2 cars when they use the same engine with different bolt on parts.

ambystom01

iTrader: (7)

What car? I had DS2500s on my car and they were fine, wore really fast but other than that fine.
The drivetrain as used here only includes the diffs, maybe. I believe the Ralliart uses the same hubs as the GTS and I suspect the axles are either the same as well or a unique piece, not the same as those in the Evo Ix or X.

jcm308

Not a car you get in the USA.

I also know quite a few other people that have has similar issues with their cars at the track. I know alot less that had issues after using brake setups that were designed as track orientated street units (Brembo, Project MU, AP Racing etc). Yes there were a couple of exceptions but overall the consensis was the same.

ambystom01

iTrader: (7)

I'm not in the US so what car?
Most braking issues can be solved by doing a bit of research before hand. You can find out what pads have a suitable operating temperature and go from there. At worst, you still have braking issues and know for sure that you need to upgrade. More than likely though, you'll save yourself several thousand. Remember, with brake upgrades come more expensive pads (and possibly harder to find pads), more expensive rotors (and possibly harder to find rotors) and potential wheel clearance issues.

jcm308

It was a VW Polo GTI.

I did a hell of alot of research before finalizing what setup to go with and as stated I was very underwhelmed by the end result.

Other street/track cars I've owned where I've done brake u/g include:

VL group 3 commodore (another car you don't get there)
S13 Silvia
XE Falcon S-Pack (Aus only)
XR6 Falcon (Aus only)

There are more but that should be enough to prove a point that I'm no where near new to this game.

ambystom01

iTrader: (7)

I've heard of the Polo GTI but we don't have it in Canada either.
There are a lot of factors that go into deciding whether brake pads will work well or not. As I said, on my car (not the lightest car out there nor does it have massive brakes), I had zero stopping issues with Ferodo DS2500s. This was at a big track (top speed of 230 km/h in my car, highest speed braking zone is from 230 km/h to about 100 km/h) and a small track (top speed maybe 140 km/h) and with temperatures as high as 30-32 degrees celsius.

jcm308

The track I was at had a top speed in the Polo of 170km/h with the slowest corner being 40km/h. Ambient temp got to 35 degrees celcius.

Good to find someone that talks in decent figures (km/h and celcius). I would have had a hard time converting to mph and farenheight).

ambystom01

iTrader: (7)

With those speeds, I'm unsure why the DS2500s had issues. What size rotors and calipers did it have (piston number)?

jcm308

324mm rotors (I think) and stock (single pot) fronts.

As I said, I did a rotor, pad, fluid and line u/g only. All reputable brands (no chinese knockoffs).

ambystom01

iTrader: (7)

324 mm rotors, on a Polo? That's a 13" rotor, hell, that's bigger than what's on the STI and I think close to the same size as the Evo X. What fluid did you run?