Learn me: Brakes for the track

I have a 2011 VW GTI with a Stage 1 tune. It's my DD so I can't go too crazy setting up it for the track. It makes about 210WHP and weighs about 3200lbs RTR. I installed a Brembo 330mm 4 piston BBK with one piece rotors and RS3 brake deflectors that are supposed to help cooling. I took the car to Laguna Seca a couple weeks ago and managed to warp the rotors after my 5th 20 minute session. I was hitting about 110 mph on the front straight. I've also been told that LS is a pretty brake intensive track.

I'm getting all kinds of different information so I thought I'd ask a few questions here.

Is it possible that I just didn't let the rotors cool enough on my cool down lap? I was having a ball that session and I set my fast time. I kept pushing until the last couple corners. I *think* I did a couple minutes of 5-10 mph loops in the paddock afterward but I can't say for sure.

My thoughts are that I probably need to:

1. Upgrade to 2 piece rotors that will cool better.

2. Improve the airflow to the brakes somehow(bigger/better deflectors, ducts from the front bumper). 

3. Upgrade to a track pad, most likely Hawk DTC-60s.

I've been tempted to buy a bigger set of Brembo calipers off of a Cayenne that use larger 350mm two piece rotors but I was warned that the calipers in question would need a bigger master cylinder or I would get more pedal travel. They might also throw the brake bias off even more to the front.

So, what say you dorks? Will better pads help keep rotors from warping? Will a two piece rotor be better able to resist heat soak and warpage? Should I give up now and buy a Fit/Prius/Model 3 and forget about tracking?

Proper ducting can make a huge difference if you already have fairly competent brakes which it seems you do

You didn't mention what pads you are running currently. Typically the rotors don't actually warp but the pads overheat and start to transfer (unevenly) onto the rotors causing the pulsing that you feel through the pedal. I think you will be fine with some proper track pads with a fresh set of rotors (and maybe some fresh fluid). Hawk makes good pads but you'll want to be careful to not go to extreme with them depending on the tires you are running. If you are on street 200TW tires or less maybe the HP+ is more than enough for you, I've had good luck with these and the older street/race pads that aren't available anymore on my car at our small but very hard on brakes track local to me.

I'd be willing to bet with proper track pads your stock braking system would've held up just fine even with the extra power but I'm not a GTI expert.

Adam

First, have you checked runout on the rotors to verify if you have actually warped it, or if you're feeling uneven pad deposits?

If you didn't have track pads on the car, chances are that you overcooked the pads, not warped the rotors. I've run Laguna Seca in cars of somewhat lesser performance (Mazda RX8) and didn't have brake performance problems, but then again I was running track pads. The Andretti hairpin and the turn onto the front straight are (IMHO) the two corners that are really hard on the brakes, the other ones not that much, at least for the sort of hamster-powered machines I usually drive. And between turn 11 and the Andretti hair pin, your brakes should have enough time to cool down a bit.

Right, back to brakes. You need to find out which component let you down (most likely pads if you weren't running high temp track compound), plus you probably need better cooling for your rotors, so I'd look into brake ducts. But either way, without figuring out what went not quite right you'll end up loading up the parts cannon and blow a load of money for possibly not that great a result.

+1 for you probably just suffering from uneven pad transfer onto the rotors from high heat.

If so, one way to address that is to buy those (expensive) DTC-60s, put them on, do somewhere around 5-10 cold brakes applications, after which your rotors will be cleaned up. 
 

That pad is very abrasive (and noisy, and dusty) when cold. 
 

Or, you could just replace the rotors or have them machined, but where's the fun in that?

Ducting ducting ducting.

And another vote for material transfer.

I did overlook that. Look for proper track packs and use a dial indicator if you wanna check if your rotors are actually warped. 

I've had fantastic usage and customer service with Carbotech pads. I have been happy enough with them I haven't strayed enough to give opinions on full track pads from other brands other than Hawk

I have never actually seen a rotor warp.  It has always been uneven transfer of pad material.  This is from when you get the pads VERY hot and then stop the car.

More cool down will help.  

Brake ducting will probably cure this issue.

I'm not up on the latest features on various autos so I'll ask:  Does your car have any kind of stabililty control or traction control system?

I have seen cars cook their brakes if the system on that car uses the brakes to "help" the car around corners  or limit tire spin as most do.

If yours does, try to find out how to turn it off while on track.  If you can, be prepared to have to drive the car through the turns as it won't be doing it for you.

But your brakes will love you for doing this.

The OEM's put such nice brakes on todays cars but when you take them on track these systems can burn them up in just 1-2 sessions on track.

+another 1 for uneven pad transfer layer rather than warped rotors.  Those brakes should be plenty for that car.  
 

Try a more track friendly pad compound next time.  We swear by Raybestos ST43s for track time on street tires on our fleet of Lemons cars of varying weights/power/size.  Call Wendy at Porterfield Brakes to get them.  Zero rotor wear, easy to modulate, last us about 3k  racing miles, never ever faded on anything to the point of heat that we cracked the rotors.  

Another vote for uneven pad transfer. The G35 does this due to a lack of brake cooling.

Aggressive pads will help remove the deposits, but they won't be very fun to DD. I switched from Power Stop Track Day pads to EBC yellows. The rotors were clean in about 40 miles. Ducting is on my list but finding space in the front of the G to run them is going to be a challenge. 

Yes they were actually warped. I turned them on my lathe and got them to within .002" of runout. 
 

I was using Brembo's FM1000 pad which is their street/autox/light track day pad. They were shot at the end of the day. I replaced them with a set of PFC Carbon Metalic Z rated pads. They are similar to the HP+/HPS pads. I actually like them better on the street than the Brembos because the Brembo pads had too much initial bite. These are much more progressive. 

Yes, the car has stability control and traction control. I left both on because it doesn't have an LSD. 

Not buying the rotor warping thing.   I use to run stock brakes on my TR8 ITS race car.  Aggressive pads on stock sub 10" non vented rotors.  They literally would glow red for my 45 to 1 hr race sessions.  Never ever warped.  Wore out fast, cooked the grease in the wheel bearings, and cooked front strut inserts, but never warped a rotor.  Check all of the mounting hardware.  Check the wheel bearings.  Do a simple run out test.

If I mount the rotor on my lathe and I can see it running out does that count?
 

I  don't remember the readings but I took about  .020" per side to get them cleaned up and running true. 

Have you ever tracked the car with the stock sized brakes? Did you encounter similar issues?

Was the BBK new when you put it on? Just wondering if it may have had prior issues to you putting it on your car.

CAinCA said:

If I mount the rotor on my lathe and I can see it running out does that count?
 

I  don't remember the readings but I took about  .020" per side to get them cleaned up and running true. 

OK, going back to the original questions. 

I would say track pads won't help with rotor warp. They will help with braking, they will not fade as temps go up, but they will not reduce brake temps. If anything they may go up because you will use them harder because they keep working.

Cooling would help. If you can reduce the rotor temperatures, there is less chance of warping a rotor. There is also a lower chance of pad transfer and the pads will last longer. This is where I would start out. 

After they throw the checker flag, get out of it. I usually try to do the cool down lap without using the brakes at all. 

The two piece rotor question would be a good one to call Brembo about. 

As a BMW guy, there's a few screwy technologies happening on brakes on some cars. DSC which only acts on rear wheel brakes, keeping the back end in line at the expense of your consumables. Automatic rotor drying, which drags the pad lightly when the rain sensors are going. Then there's the LSD emulation via brakes.

None of those will kill you in one lap, but they make a strong case for an old, analog track car. 

Pads that are actually somewhat pleasant on the street simply don't work on the track.  Get a set of street pads and a set of track pads and swap them over.  Hawk HPS/HP+ are street/auto-x pads, they won't hold up at the track and neither will any other pad that's in that same class.

For years I ran the Hawk DTC70's but that was on a 3000lb 500+ hp car.  On the GTi I'd try the DTC60's.  I also use PFC08's or 11's, which are great, just don't let the brake dust get wet if you like your wheels.

While I wouldn't track a car on HPS, I've run more than one car on HP+ on the track. IIRC TR even advertises them as track capable pads.

Doesn't mean that proper track pads aren't better, though.

Rotors can and do warp, especially cheaper ones that may have a bit too much core shift, or some "twang" left in them after they were machined the first time because they were machined too soon after being cast.  (Usually once a rotor warps, you can remachine it and it will stay true, because it stress-relieved itself)

That doesn't mean uneven pad transfer doesn't also happen.  It's like the eight blind men and the elephant in this regard, a lot of different things can cause a pulsation.  Installing with runout will also cause a pulsation after a while due to uneven pad transfer and uneven wear, from the pads always grazing their side's high spot while off the brakes.

That said 5-10mph is not really enough speed to cool the rotors down, you need 30+mph to get the internal fan action happening in the vents.

If the dust shields are still present behind the rotors, try trimming them off everywhere there's an opening on the suspension side, but leave them in place as heat shields over ball joints, tie rod ends and the like. I removed them on my RX-8 and it made a noticable difference.

I built my own ducting setup for my WRX using a mix of hardware store items, C6 Z06 ducts to get around the wheels and some proper 3" high temp flex hose. I used some plastic 3" to 4" adapters from the hardware store to hook hose up to the Corvette ducts, used them in the fog light holes as intakes and cut, bent and riveted some metal 3" furnace ducts into the stock dust shields. Much cheaper than any off the shelf solution and still has just as much functionality. I take the wheel well hose off and swap the non fog light front corners in the winter, then put it back on before any track time.

I used DTC-60's on my RX-8 and loved them for track use. If they made them for the WRX I would have gone that way, but there's very little choice for track pads for that particular brake setup.

One thing I don't think we touched upon yet is - what pads are actually available for the Brembo BBK the OP has? After all we can recommend pads until the bovines make it back to the barn, but it's not useful if they're not available for this BBK.

In reply to BoxheadTim :

One neat thing about Brembo, it seems like they don't really vary much.  As far as I've been able to ascertain, every front 4-pot uses the same pad dimensions.  The only gotcha is thickness, and the Volvo weirdness I live with made that clear.  In short, the STI and Evos (what you'd normally find performance pads for) have 30mm thick rotors, but teh Volvo has 32mm thick rotors.  The difference is made up not with the caliper body, but pad thickness.  You can't fit pads meant for 30mm rotors without machining some of them away.  (Or cutting the rotors thinner I guess)

330mm diameter rotors make me think this is the same generic setup because SO many manufacturers using Brembos magically have 330mm rotors.

One very important piece of info I learned from tracking my GTI is that the traction control utilizes the ABS to limit wheel slip. If the traction control light comes on on your dash, you are cooking your inside brakes on that turn. You can upgrade the pads but that's just treating a symptom.

Ducting is difficult to come by for GTIs, the drivetrain, foglights, and various reservoirs are pretty much entirely in the way. With the FSI engines, before they changed the design of the lower control arms, the brake ducts from a Porsche GT3 fit on the arms and I was able to feel a difference on track, they stuck down a couple inches below the car and threw air wuite nicely at the rotor area. With the TSI engines, the control arms are deeper and the ducts don't fit. I would suggest looking for something like this, unless you want to start cutting things out of the car.

Hawk brakes are quite nice, HP+ is a good way to go. An important thing to help with brake heat is to stab the brakes, not drag them. Get on them when you need to slow down and get off them, don't linger or you're just adding unneccesary heat to the system.

BoxheadTim said:

Have you ever tracked the car with the stock sized brakes? Did you encounter similar issues?

Was the BBK new when you put it on? Just wondering if it may have had prior issues to you putting it on your car.

I did track it once on the stock brakes with Castrol SRF brake fluid. I ran Pilot Sport A/S 3+ 500TW tires so I was traction limited. This time around I was on a set of Direzza ZIIs that are 200TW. I was pushing a lot harder than the first day. FWIW I cut 8 seconds off my personal best. 

The BBK was not new. It had about 20k miles on it when I bought it. I put 10k and about 40 autoX runs on it. They were smooth until the 6th session. I went out and the first time I felt the brakes pulsing (probably pad transfer). They did get better after a few hard brakes, but they had that pulse from then on.