tracked01z06

I'd like to discuss several things in this thread, in regards to my car on the track. Quick background info on the car is that it's (as the title suggests...) an 01 Z06 on stock suspension (Although slightly lowered on the stock bolts) and running on Firehawk Wide Ovals, which I have been really surprised by. Very good amount of grip for a street tire, even with the aggressive race pads I run, which I'll talk about a little later on.

First, I'd like to talk a bout coolant temps. I hit between 240 and 255 degrees in each session. I never had a check engine light come on, I read a thread here on CF that said it would only kick on at 256 or above. I'm wondering if anyone can tell me what's the chance that I've done damage to the motor all ready? How much abuse can this motor take, in regards to high water temps?

Second, I'd like to discuss brake pads. The last two track events I've run at, I've used Carbotech XP12s (front) and XP10's (rear). My feedback is that they have good initial bite and then good consistent feel after that. They also didn't take long to warm up. They did squeal and brake dust pretty well though, which I expected and didn't have a problem with. My only issue is that the fronts are gone...and I mean gone...after only 1 and a half track events (that's 3 and a half days of 3 sessions each day). The rears by the end of the weekend are pretty much shot as well. My question is, is that normal life expectancy from a race pad or just a characteristic of the XP12 and 10's? Is it my driving style? I've been told I brake late/deep. I admit, I do like to use my brakes to their full extent.

Third, I'd like to discuss brake fluid. I currently run the ATE Superblue and I think I'm boiling it. I run stock calipers, stock rotors, the carbotech race pads and SS brake lines. I bled my brakes Friday night before the track, then Saturday night and again Sunday. Saturday night I got 3 full brake pedal pumps worth of air on each corner. I checked each brake line fitting to make sure they were tight and there were no leaks. As far as I can tell, there are no leaks anywhere. The pedal got a little softer as the day wore on, which is why I bled them Saturday night (I know I should be bleeding them regardless, just saying I knew that I HAD to because of the increased pedal travel). I had the same situation on Sunday and bled them again half way through the day. Again, got air and really dark fluid from each corner. Someone at the track recommended the Motul 600 as a better fluid, I guess it has a higher wet and dry boiling point. Can anyone confirm that the symptoms above sound like I'm boiling the fluid?

Another thing I'd like to cover are the calipers themselves. The fronts have turned black and I cooked the rubber boots off the pistons. I'm going to have them rebuilt as far as I'm concerned, or at the very least have new boots put on. Does anyone have any other suggestions for calipers? Besides simply repairing/rebuilding them?

I appreciate all the input, I've done some reading here on the forums and know there are a lot of experienced drivers that I can learn from. I really appreciate everyone taking the time to read this and any and all input I receive.

-Bill

longdaddy

take your radiator out and clean it with a pressure washer. you will drop your coolant temps. it is unlikely that you are damaging the engine but you should watch oil temps.


as far as your brake wear, I would guess you are running with Active Handling. if that is indeed the case, the wear is not abnormal. If you are driving agressively on street-grade tire, you are activating your brakes a lot due to AH - fronts on entering the corner and rears midcorner and on exit, this would also account for fluid issues.

Having said that, this amount of air is unusual. I would rebuild/replace the calipers ASAP, just to be safe. Rubber boots melting is "normal".

when you rebuild the calipers, you can put stainless steel pistons in which will help isolate the fluid from the head. you can also put heat shields/shims between the pads and pistons to further insulate your fluid.

the problem is that the heat will have to go somewhere else and you will start seeing more wear on your pads and rotors.

I am assuming you are already running cooling/ducting for your front brakes, if not, it will help (although not by much)

Pedal getting progressively softer throughout the day can also be attributed to pad taper, especially if you are going through the pad material rapidly.

mgarfias

Your water temps are scary, at those temps you'll be puking coolant on the track. Yank that stock radiator and put in a good ron davis unit. If the car is exclusively tracked get an external oil cooler, if its still a street car get the integrated oil/water heat exchanger.

I used to see temps like you have now, but since the ron davis radiator went in I haven't seen above 225. I put in a 160 deg tstat while I was at it (lived in AZ) and it was fine for the summers, but any other time the car will not heat up and the PCM tosses a tstat broken code (P0128).

Sounds like you are boiling your fluid, does the pedal get soft through your session? If so, flush the brake fluid between sessions. Get your self a set of the DRM cooling ducts, and one of the deals to put the hose on the spindle.

Don't bother replacing the dust seals on the calipers, they'll just disintegrate again. I gave up on the factory calipers and put a set of wilwoods on (wide-5 SL6R) using an LGM mount. Still on the OE-style rotors, but I expect that to change. The reason I went to the wilwood is that the OE calipers just end up spreading, and you taper the pad top to bottom (not leading to trailing).

Pad wear sounds about right when you lean on them. Oh, the wilwoods I have use a 20mm thick pad and cost less than pads for the OE calipers.

tracked01z06

longdaddy,

I am not using the active handling. I have it disabled at all times on the track. This car is my daily driver, but I do have another car I can drive. I keep it for just these times. The calipers will be rebuilt within the next week or so hopefully. I am only running the stock brake ducting, I don't have anything additional on the car yet. I have a picture of the front pads, the material is pretty much gone. There is some slightly in the middle of the backing plate and absolutely none at the outer edges.

mgarfias,

I agree, when I saw the water temps I pitted just to make sure they would come back down. They did, rapidly. But still cause for concern on my behalf. I will definitely look into the integrated oil/water heat exchanger. Who sells one? I may just put in an aftermarket radiator and lower temp thermostat.

The pedal does get softer throughout my sessions and yes, I will have to bleed between sessions if I stay with my current fluid. I will almost certainly change it though for the Motul. The BBK I'm sure is the way to go, I just don't have the funds right now though.

Thanks for all the input guys, I really appreciate it!

-Bill

RX-Ben

The engine is resilient. I hit high 260s repeatedly, boiled the fluid over at the beginning of a long session, drove off-track until temps were in the 220s, then hammered it again for 15min, stopped around 260+, drove around, hammered again for another 12min. No problems. Oil temps and the resulting pressures are more of a potentially fatal issue. You'll get a high oil temp/reduce rpm message when they get too high. You can't just stop when these get too high b/c of heat soak - you need to drive around to get air moving to drop the temps. Keep this in mind on your cool down lap and drive around a little if your cool-down lap was too fun.

I have not checked my piston boots but I assume they are gone. Not the end of the world. Order replacements, get a brake ducting kit, get the DRM stainless pistons, rinse and repeat with the piston boots as needed. You'll have to do this with any caliper. Racing caliper lack these dust seats b/c they burn off anyway. You need to rebuild these on a street car (or clean the pistons regularly to prevent scoring of the piston bore).

For pads - I have CL RC6e. Plenty of pad left after 2 days of abuse on an abusive track (pocono north). I recommend them (see CL brake thread).

For the fluid, I use the Motul 600. I got some play in the pedal towards the end of day 1 (when I started thresholding). After a few turns, the pedal came back up a bit. I actually liked the lower pedal for heel/toe. Second day, dropped a little more. I am not running ducts or the stainless pistons yet. I am not sure if you have boiled fluid (vs. abused). Either way, the Motul is 593F boiling vs. 536 for ATE (IIRC). Cheap upgrade, worth the marginal diff. The Motul 660 is a misnomer (~615F). Castrol SRF has a slightly lower max point than Motul, but an astronomic wet bp. Super $, and if you flush after track events, moisture isn't a bit deal. Depending on how many times you flushed, you may have had gunk in your calipers/lines or gunk in your abs module that got injected into the fluid.

Tracking is destructive, but keeping on top of the required maintenance is cheaper than replacing parts/getting stranded at the track.

mgarfias

For the radiator, call Ron Davis. A quick google search will get you to where you want to go. They make two radiators, one with the integrated EOC and one without. I have it with - the biggest downside is its on the right hand side, so you have to run lines over there.

Hmm, now that I think about it, DRM sells these too, and they have a good line kit with all of the fittings and stuff you need. I didn't do that and ended up mixing and matching. Of course, I also put on a remote oil filter which their stuff won't be setup for.

I really like the Ron Davis radiator compared to the other ones I've seen. They're complete works of art, totally tig welded, no stampings, and all the machined bits are nicely CNC'd. Only mod to put it in is you have to open up the rubber radiator holding pads.

Remember that any time you're over 220/230 the PCM is going to start pulling timing on you, and at the same time, the hotter you are the more likely you'll be to detonate.

RX-Ben

Also - you can go w/an air-oil cooler - if you drive on the street get the Mocal take-off plate w/200deg thermostat. It is a cheaper setup assuming you don't need a radiator.
You should run lots of water (60/40 or more in the summer, though you will need some anti-freeze to lube the pump&seals) and water wetter (or 2 drops of dish soap). Also, the above-mentioned cleaning is a great idea. Lots of people get by on the stock radiator.

2000BSME

I had to get a big radiator to keep temps from 255*+.

longdaddy

stock ducting does not do anything except blowing air at the tires.

if you are not using AH, maybe your track has some harsh braking zones? killing the pads in 1.5 days is pretty extreme unless you are getting some serious track time every day.

by the way, running the pads down to the plate is a sure way to boil the fluid - see my post above about insulating the pistons.

if cleaning the radiator and replacing antifreeze with water + additive does not help, I would invest into a bigger radiator and/or oil cooler.

i went from boiling coolant on hot days and 300+ degrees oil temps to normal coolant temps and oil in 245-260 range by just cleaning the radiator and installing front-mounted oil cooler.

i have never used XP12s on the front, but I used to get about 3 days (~5 20 min sessions each) on XP10 back when I ran stock calipers, this is with swapping the pads around after every day to equalize taper and full front ducting.

to summarize, you are not experiencing anything unusual for these cars, but your case does seem to be on the more extreme scale of what people experience at DEs. Time to buy some parts, I suppose.

ScaryFast

I'd take longdaddy's suggestion before spending $500 or more on a new radiator. yes, the AFtermarket parts are great, but there are a LOT of people here that ran Z06's hard on track with stock cooling systems and have no problems.

Maybe if you're in the south and ambient temps are much higher perhaps it's necessary, but try making sure your stock cooling system is functioning perfectly before spending money.

Is all of your ducting intact? Lots of people rip off the undertray on a parking block or driveway. If it's missing or damaged it won't effectively force air through the radiator. Also, leaves and debris like to collect up there. Clean it out.

sothpaw2

Hi Bill,

It was good meeting you at Summit! Longdaddy here is correct I think that Summit Main is partly our issue w/the brakes--it's really hard on them. VIR is much less an issue. Main is 140mph-40mph at T1, then maybe ?120-73mph at T3 seconds later, then ?115-40mph at T5. All right in a row--murder on the brakes.

I was still getting longer pedal issues w/the Motul but I have rubber lines. Maybe some of this is pad taper? I lubbed my slider pins so that's not it. My pads were new out of the box on day 1 so there's no exuse for me to have to bleed after day1. Maybe to run Summit you need SRF in these cars? That's a guess. My pads after day 2 were a little tapered in rear and front but along the length.

On the cooler--we were running very hard in that group. I had a new-to-me DRM standalone oil cooler. This is very inexpensive ($650 from DRM) and my oil temps were most typically 235 oil w/ water at 220. I think one session I saw 252 oil and 230 water--that's about it. I would recommend this route to save $$ over the integrated one, wherein you must remove your rad & replace it. TPIS also makes a stand-alone oil cooler.

On the calipers--mine did bake a little (1st time) but not like yours. Who told you to rebuild? If the pad taper isn't width (narrow) direction, I don't think you touch these. The seals don't go--they cause extreme taper first.

Andy

tracked01z06

Andy,

It was great meeting you as well! I appreciate the helping hand swapping the pads and all. I will definitely pick up the DRM oil cooler and I will simply clean out / flush the coolant from the stock radiator and do a 60/40 mix of water and coolant.

Longdaddy,

I appreciate the responses. For now I'm going to simply switch to the Motul 600 and clean the radiator and put in a mix of coolant and water with some water wetter. See how that does at my next track weekend. I will inspect the calipers and make sure they are not damaged besides the boots.

ScaryFast,

Again, thank you for the advice. I actually just replaced the 3 piece front spoiler because it had been damaged several weeks ago. So that is in good shape, but again, I think cleaning and making sure the stock cooling system is optimal would be the next best step.

RX-Ben,

I actually read the CL pad thread the other day and am very interested in trying those pads out. I'll give them a shout and see how much they are for a set. For now, my buddy Andy sold me a set of Wilwood J pads which I'll use until they're gone.

Thanks everyone!

-Bill