What is brake fade?
Brake fade occurs anytime the brake temp rises beyond the effective operating temps of the brake pad. Excessive heat can do major damage ranging from a spongy pedal to a snapped brake rotor. The most common type of fade occurs when the pad itself over heats and looses its ability to slow the rotor. If the pad temperature gets hot enough of it transfers heat to the fluid and can exceed the boiling point of the fluid causing air bubbles to form in the lines. This causes a spongy pedal and a decrease of pressure the piston can apply to the pad. This situation gets worse because the pad must be in contact with the rotor for a longer period to get the same stopping power. So basically the best way to avoid brake fade without changing any hardware to apply harder brake pressure for a shorter period of time. You want to apply VERY firm pressure for about a second or 2 then get off completely. Braking slowly for longer is worse then braking hard for less time when dealing with pad fade. This is what I have experienced and it seems to be backed by info I've seen on brake fade and high performance driving.
Most beginners overuse their brakes on the track because they don't really know how much speed they can take into corner once they find a workable line. I have no idea how people mange to get fade during street driving but many people claim to. Braking really late and really hard isn't practiced my most of the people on the track during performance driving schools either because they don't know how or because it is a little more aggressive and can be dangerous if you don't know how long it takes you to stop. With a little practice threshold braking can be done safely if you give yourself enough room.
The stock brake experience!
I started thinking about how to improve the brake performance of my car the first time I experienced brake fade on the track. I wanted to go buy big brakes I didn't want to spend the money. I talked with people at the track and tried to learn about the causes of brake fade in high performance driving situations. Driving with brake fade can teach you a lot about driving because you're not using massive brakes as a crutch. In the past, my brake pedal would sometimes sink all the way to the floor and the car would hardly slowdown. This taught me how to find the right line and carry more speed through the corners. Not being on the right line and being unable to slow down usually sent me looping through the grass and weeds @ a high rate off speed. Not quite what I was trying to do but it seemed to happen a lot during my first few track events.
My first hardware brake upgrade was an EBC Red pad for the front and green in the rear. This helped so much I was convinced I could make the stock brakes work for my needs, or @ least temporarily. This pad wore out very quickly so I started looking for another option. I learned from talking to experienced drivers the EBC Red was not a good pad for a heavy car and I needed to use a "real" race pad. I started talking to a guys @ the track about all kinds of different pads and several owners of fast cars with stock brakes said I should try Carbotech Panther XP pads for the track. They seemed to know what they were talking about so I did some more research and decided to buy a set with a full set of 6 stainless steel line and Motul 600 fluid. I picked this fluid because it had the highest dry boiling point and received good reviews. It was expensive and very hydroscopic but seem to be one of the favorites. I installed my new stuff and went to the track.
These changes totally transformed the brake system on the car. The new pad never faded @ all, had great bite and release characteristics and seemed to last forever!! I used the pad all day and it didn't wear @ all. The Carbos lasted for around 10 track days but don't really remember. I was getting faster and faster on the track and the pads still had more to give. Once the pad started to wear down I experienced some fade because pad temps rise as the amount of pad material decreases. I knew if I could just get rid of a little more heat the brakes would be fine.
I found several different options but I decided brake vents would be the best solution if I could make them fit on my car. I found kits on-line for BMW but nothing for Audi. I started doing different designs and playing with parts I got at the hardware store but never got anything set up that was clean enough to use on a daily driver/track car. The first day of this season my track pads only had about 5mm of material left and faded significantly at Gingerman. I ordered a new set of pads and decided it was time to use what I had learned and install a set of vents before the next track day. The results were fantastic so I've put together a little "how to" install brake vents on an a4. Enjoy!
How to build "Phil TypeR" brake vents!
Note: This is mod isn't difficult but does take some experience with tools. I think anyone can do it but be ready to spend a full afternoon to do it. If you don't feel comfortable cutting your car then you need find a shop that sets up racecars. As a side note I don't think the brake vents will work for anyone who wants to retain fog lights because that's really the only location for the air scoop. This project worked great for me but don't guarantee any information here because they've only been on my car for a very short time. I've included some pictures at the end to help visualize what the end result will look like. Enjoy!
The tubing (1)- I used a 12ft length of 2.5-inch tube purchased from Pegasus Auto Racing supplies www.pegasusautoracing.com. (part # 3621-2.50-12foot page 99 in catalog)The tube is orange colored and able to withstand a surface temp of 500 deg. it's very durable, light and costs about 90 bucks. I got the high temp durable stuff to because the route it takes from the front intake to the rotor is kinda crazy and subject to heat and vibration.
Intake (2)- a plastic air vent usually used on racecars and costs 16 bucks apiece. Many styles exist but you'll want the one I got for a 1.8t. NACA duct part # 3627-black
Metal hose clamps (4) 2.5inch size costs about 4bucks @ any hardware store. Used to attach hose to mounting points.
Several long zip ties for keeping the hose in its proper location in the wheel well. The zip ties should also be used to secure the vents behind the front bumper.
Metal bracket (2) this bracket is riveted to the "splash guard" on the brakes. If you don't have a splashguard you'll need to fab a bracket of some kind. Metal flange is made out of aircraft aluminum and costs about 6 bucks a piece. You could use 2 more for an intake if you are really tight on space like on an s4. They cost about $7 and you'll need 2. http://www.aircraftspruce.com
The part # is 10350-10 ALUM FLANGE 2-1/2
Jack up the car and pull off the front wheels
Pull off bumper and belly pan
Remove brake calipers
Both wheel wells
Measure and mount tube flange- flange should be mounted on the top of the rotor and a little forward with about 1/3-1/4 of the opening showing above the rotor (this will help promote air flow by not allowing the air to become stagnant). It will be mounted just above the abs sensor so make sure you allow a little room for that. Figure out where you want it and cut out a little section that matches the round edge of flange. Line it up and clamp the 2 pieces together with a set of vice grip pliers. Drill 2 or3 holes through the pieces, rivet them together and reinstall the splashguard w/ flange.
Driver side wheel well
Route tube- Starting from the front of the car; stick the house up in between the intercooler shroud and the radiator. This location is very tight and you'll need to grind away some of the plastic (see pic). The tube enters the wheels well in front of the shock. Connect tube to the flange w/ hose clamp. Zip tie the hose loosely tucked in the little notch in the wheel well in front of the shock. Now make sure you can crank the wheel all the way in both directions and tighten the tip tie once it everything looks good.
Driver side front bumper
Remove the plastic notch too your liking and trim intercooler shroud so the tube has a smooth route. You may want to add some protective covering in areas where the tube comes in contact with sharp edges. I spent a lot of time trimming everything but its really not much cutting. The hose will push the intercooler shroud away from the car and make Bumper fitment very difficult if you don't do this right. you could also trim your bumper on the driver side almost like you do when installing rs4 intercoolers on an s4. To see info on how to do this see the s4 intercooler install instructions on www.goapr.com don't remove the strip the like they do but instead remove the small pointed triangle area they leave intact. Look at everything carefully and cut hose to proper length. Make sure you have your plastic intake in hand to insure proper fitment the first time. Test fit bumper if you wish.
Passenger side hose route
This is this worst part of the job so be prepared to rip up your hands. The tube starts by going in between the AC lines then snakes its way round the inside of the engine bay and goes around the starter motor. A wire mount is the only thing you many need to move out of the way. This wire is located below the starter and pops out with a screwdriver. The hose will be very tight through this area so just look for the areas with the most room and start working the hose through. The hose should then pass underneath the catalytic converter. I don't have a cat anymore so fitment through here might be a problem for people. From this point the tube passes into the wheel well and mounts up just like the drivers side. Once you get the hose all set do the same steps you did on the driver side. Cut the hose and position the intake however you want. Zip-tie everything and double-check your work. Put the bumper back on and reinstall brakes and wheels.
You're done! Congrats on completing one of the best and least expensive mods for your a4. You shouldn't have any more problems with brake fade at the track!
e-mail me any questions and please let me know if you run into any problems or think I need to add more detail firstname.lastname@example.org
Feel free to Paypal me some green for putting this write up together and solving all your braking problems!!!! - Philthrottle (typeR)