I have resisted from posting the past several months regarding the stock brakes due to the fact I'd just sound bitter. But now that they seem to be fixed I'll let her go.....
First off, as many have already concluded, the stock C6Z brakes are just fine for the street but absolute junk for track duty. My experience with them made me absolutely hate the car and I seriously thought I made a mistake trading in my '03Z for this "it's all good until you have to stop" kind of car.
My "bitterness" tour started at Road America this past April. Having driven several hundred miles to enjoy quality track time only to sit out about half the sessions messing around with the brakes just infuriated me. The sessions I did run were about 6/10's at best because I never knew if the brakes would be there for me. I really thought I was properly prepared.. LG spindle ducts, Motul fluid, Carbotech XP11 pads, spare rotors. With the stock tires the brakes were marginal at best, with a soft pedal after about 3 laps. With the slicks on, the brakes were good for the first lap, soft pedal on the second, and to the floor by the third.
At the time I couldn't figure out why I'd get a soft pedal so quickly, especially since no air would come out on each bleed (oh yes, I bled between every session... what fun!). What would come out, however, was dark brown to black Motul fluid. The brakes were obviously past hot. It turns out the stock brake lines were starting to fail and after a through inspection upon my arrival home they had failed where the rubber inserts into the end fitting near the caliper. So, LESSON#1:
STAINLESS STEEL BRAKE LINES ARE A MUST!
Ordered them from LG (what a great crew!) and put them on before my next event at Heartland Park. So with new lines and fresh pads I performed some test laps on the stock runflats to see if the problem would return. After about three laps the pedal would get a little soft but it was tolerable. What wasn't tolerable, however, was the chatter back and forth between the front wheels under heavy straight line braking. My '03 never did this on this track so I believe the crazy stock setup was the culprit. To fix this I called up LG and ordered the StopTech front brake package (again nothing but great things to say about LG Motorsports).
I took the car to the track for the first time with the new setup yesterday. It was 103deg outside so I think it was a good heat management test. I ran the stock runflats and built up braking to about 8/10'ths without any fade or chatter. My confidence is back with the car and I'm happy once again. I'll be going back on the 18th for a weekend with the slicks. I don't anticipate any more problems.
So all in all, if you buy the car to enjoy it on the track, budget a few extra thousand for a brake upgrade or you will most likely be disappointed.
Rant over.
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'03 EB Vararam, B&B Bullets, BK Harness Bar, Goodridge SS Lines, '04 Shocks (Sold)
'06 MS - RBF600 brake fluid upgrade, Recaro Pole Position Seats, Sharkbar, other safety equip.
So, all you needed from StopTech are the replacement rotors up front with brake pads they sell?
Good, thorough post.
I went with their complete brake package up front (calipers/PFC pads/slotted rotors).
A little more color..... My last track event was the first one that I didn't have to do anything with the brakes (no bleeding / removing the wheel to inspect the pads / nothing). What a liberating feeling!
The pedal was consistant throughout the 3 day weekend and there was absolutely no brake "chatter" between the wheels. It was a totally different car.
Hey bpf1970,
Glad the brakes are getting the job done for you! I always explain the situation to my customers like you did in your post...there's so much 'stuff' going on out at the track...the brakes will be one less thing to think about while you're out there, and you'll have more time to focus on driving and enjoying yourself."
I've been struggling with the braking issue too. I have noticed my Motul turning dark too, though I've had stainless replacements from Stoptech from the get go. Stock calipers, XP10's and XP12's as well.
Are you certain that the dark fluid was the result of the rubber brake lines? I'm thinking that its something else entirely - like the seals around the pistons. So I've been looking for leaks. Nothing yet.
Most ester based DOT 4 brake fluids will turn dark just by sitting. They are very hygroscopic, meaning they absorb moisture readily and much faster than DOT 3 fluids. It is for this reason DOT 3 fluid is recommended for a street car. The reason being, DOT 3 fluids do not absorb moisture as rapidly, but they boil sooner once they have, making them unacceptable for track use.
The advantage of DOT 4 fluids, such as Motul (and what I use as well) is due to its high boiling point when "wet", meaning after absorbing moisture. The drawback being it absorbs moisture faster and should be changed regularly; more often than the OEM DOT 3 fluid. This is acceptable for a track car where you perform brake bleeds and/or even flushes more often (or should), but on a car that sees only occasional track use may be unacceptable.
Like most everything about a dual use car, it's a compromise.
DOT 4: higher wet boiling point, but requires changing more often, such as when it turns dark, if not before.
DOT 3: absorbs moisture slowly, but boils sooner once it has. Requires changing less frequently.
bpf1970, I have tracked my car very seriously since I aquired it last Sept. Last weekend my Z06 went over 4000 track miles. I switched over to StopTech's very early on, after experiencing the same type of problems. I have done a complete make over of the stock setup. Stop Tech Brakes, Performance Friction 03 pads, SS lines, cooling ducts, coilovers, alignment, wheels, Hoosier Vrl slicks, and a few under hood mods, to get the car to be the track monster that it was always ment to be. Today it is as good on the track as a "street car" can be.
However I rarely street the car, 5700 miles on the car overall. The engine has prob seen as many near redline shifts as any C6 Z out there, and has had zero problems. On the track it out runs the best "streetable cars". (F430, GT3, SRT,FGT etc.). So with a few expensive and a few not so expensive mods the C6 Z can be almost, as good on the track on as a TRUE factory race car like the comp coup Snake.
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Rick Moore
LG Long Tubes, Halltech fiter & tune, StopTech 6 piston, Coil Overs, CCW Wheels, Hoosier R6's, BPP shifter, Cavvaiggo race seats, Shark Bar, Impact Harness set, 482rwhp
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