DeerHunter

I did. The set-up for Saturday (when I boiled the fluid twice) was:

• Brand-new v4 DBA rotors from Goodwin (front and rear)
• XP12s in front and XP10s in rear

That's what makes this particularly frustrating. Better rotors, better pads, cooler day, worse results.

Savington

iTrader: (31)

Sorry, I'm blind. I saw "XP10" somewhere and assumed.

Snap a picture of your rotors for me, just for curiosity.

DeerHunter

Here you are. It was hard to get the fronts into proper focus, but they look very similar to the rears (streaky). This is contrasted with a nice, even, light-grey layer on the rotors after break-in.

hustler

iTrader: (6)

Get them hot and see what they do.

TimM

I have the same issue with stock brakes on a heavy-ish (~2400) turbo car w/ 3" ducts off factory chin spoiler pointed at the rotors from 1" inside the sway bar mounts.

Going to SRF from Motul made a big difference for me. Also, chucking pads before they wipe out the center slot has become regular practice (Hawk DTC60). Kinda hate throwing away 'good" pads that are barely beyond half gone, but it's safer and more confidence inspiring than baloon pedal and knockback.

I've tried Carbotech XP-10's on 2 or 3 cars now and found them acceptable but very short lived. How much pad did you have left?

DeerHunter

I'll have to do a complete bleed before I drive in anger again. Hustler, I'll report back once that's done. Tim, I'll measure the pads at the same time I bleed the brakes.

I have the Wilwood calipers and have never experienced any issues with half-worn (or more) pads. Knockback and the like is a liability of the single-piston OEM calipers, isn't it?

Handy Man

FWIW I had a very similar setup (XP12/10, ducting, stainless lines, ATE Super Blue fluid) and never had issues with boiling fluid, even on hot days at tracks that are very hard on brakes.

Savington

iTrader: (31)

Castrol makes SRF, Motul makes RBF600.

SRF is in a completely different league as far as boiling point goes. Pretty much every high-buck fluid out there has a dry point in the high 500F range, but I don't know of any other fluid that has a wet point (wet fluid contains some small percentage of water and represents the boiling point of used fluid) above 500F.

ATE Typ200/Superblue: Dry 536F, Wet 388F, $15/liter

Motul RBF600: Dry 593F, Wet 420F, $34/liter

Castrol SRF: Dry 590F, Wet 518F, $73/liter

Rover gets ATE Typ200/Superblue, Theseus will get SRF when it breathes again in the winter. It's godawful expensive as far as brake fluid goes, but in the big scheme of things it's probably less than what you spent on your last set of pads, and it may be enough to solve your current issues.

Handy Man

And if it's wet boiling point is sufficient, you shouldn't have to change it nearly as often.

DeerHunter

There are no more track days this year. I do have a time attack at the local go-cart track on Monday, plus two more autocrosses, but they're not nearly as hard on the brakes as the Indy track. I think I'll use Motul 600 for the rest of the year and put SRF in next spring (and hope it lasts, as people indicate it should).

TimM

Yes they are in a different league. Most of us know the difference between brands and can read the specs too.

I changed to Castrol SRF from Motul 600 & 660. Yes the 660 was better than the 600 too.

hustler

iTrader: (6)

Wtih my TSE gigantor brakes, I don't think I bled the fluid once last season, lol.

Savington

iTrader: (31)

+1. It's hard to convince yourself to spend the time bleeding when the pedal feels the same in August as it did in January.

DeerHunter

Well, I picked up two 500 ml bottles of Wilwood EXP 600 brake fluid and did a full bleed. I also snapped some pictures of the pad deposits on the rotors (streaky) and the remaining pad life (decent, although I didn't measure them). The pads look a little cooked (like a ceramic without any glaze), as do the backing plates.

I went for a drive tonight and the pedal is still a little mushy, despite putting almost a whole litre of fluid through the system (using my patented ABS bleeding technique) and noting no remaining bubbles. I essentially repeated the bedding-in procedure and, although there was no fade or binding agent smell, the bite isn't quite what I remember from after the first installation (pre-track day). I wonder if the pads are a bit glazed.

Any comments or suggestions?

Savington

iTrader: (31)

The transfer layer is junk. Resurface or replace the rotors and try again.

DeerHunter

Well, that's great news! Replacing them isn't in the cards, considering they're only a week old. Do they need to be turned or can I use a wire wheel to scour them?

The problem is that I have another track day (go-cart track, so not as hard on the brakes as the Indy track, fortunately) on Monday evening. Given that Monday is a holiday, the chance of me finding anyone to do it before then is between slim and none. Is it safe to run the event, under the auspices that my brakes won't be as effective as they could be?

Mobius

iTrader: (2)

You can resurface it. Just lightly hit the rotor with the wire wheel, or very gently with a sanding wheel on an angle grinder, to take the layer off.

Couple of carbotech reference photos courtesy of Emilio.

Properly bedded has lovely bluish grey hue:


Improperly bedded has snot streaks:

DeerHunter

After bedding, my rotors looked exactly like the RH rotor in the first pic - too bad I didn't take a picture for posterity. Apparently, if things get too hot, the transfer layer can go to hell in a handbasket.

comradefks

iTrader: (3)

2nd picture with improperly bedding rotors is my car! Woot! haha

Alta_Racer

iTrader: (4)

Deer Hunter

After hard days at Statotech (the go cart track) my rotors look similar to the bottom pic, my brakes (94+ and XP10) work flawlessly there. I have yet to have fade, pedal loss, or bubbles bleeding after an event. I use the Prestone 5.1 fluid from CTC. It's cheap and will be upgraded this winter, when I turn up the power. For comparison to your times, I run 70 second laps, I am NA. If you know Grant with the white Mustang or Adelbert with the black GTR, we run quite close, they certainly out power me on the straights.

I think we have openings on the 22 Sept if you want more track time. 8am till noon