Brake Squeal
 

I recently did a track day at Laguna Seca (awesome), and afterwards my pads were totally gone. I followed this guide to change the pads and upgraded to Winmax W2 rotors. They feel great, and everything was perfect for the first couple of weeks. But in just the past few days the brakes started squealing. With nearly every stop they squeal. Could I have made a mistake when I was installing the new pads?

Not sure,from your descriptions but those pads do squeak alittle. Pretty normal for Hawk+, w2 these grades of pads to start squealing after a couple week. Now if it's like a very loud not so normal brake squeal that's a different story. If there vibration during braking too,mother check your rotors and everything. If it's a light squeak when coming to a stop, that's normal. Those are race pads after all, if you want quiet daily you need something like a W1

did you bed in your pads? I am not sure if the W2's require it though.

You didn't tell us what pads you're using. However, it's very common for track oriented pads to make a lot of noise. Even more so if you don't properly bed them. Track pads btw, are very very difficult to bed in on public roads (impossible to do legally).

it's only illegal if you get caught ;)

It's most likely that the pads are not properly bedded. Something to keep in mind is that brakes run in two modes under normal operation, friction and boundary layer (this is a gross oversimplification, but it may help you). Friction braking is what is takes place in most road cars, where the pads and rotors never reach extreme temperatures (aside from the occasional emergency stop) and it's only the friction between the pads and rotors that generates braking forces. Boundary layer braking is what takes place in competition cars, where the pads and rotors are operating at the limits of their temperature range and a literal thin boundary layer of pad compound has been chemically fused to the rotor by heat and pressure. This layer alters the coefficient of friction, braking forces are generated much more efficiently, and the initial bite and release characteristics are idealized. Bedding a pad is what creates a semi-permanent boundary layer, and continued extreme use will keep the layer present. With some exceptions, mild racing pads are generally quiet while the boundary layer is present.

My guess is that your new pads have not been properly bedded, do not have a boundry layer, and are braking in friction mode which is generally noisy for a racing pad. In addition to being noisy, using racing pads in friction mode can often create high wear for the pad, rotor, or both. You likely need to properly bed the pads to create a boundary layer (there are lots of posts explaining how to do this) and then regularly reach sufficient braking temperatures to maintain it. If you fail to do that, braking in friction mode will remove the boundary layer and the pads will soon get noisy. If you can not do this on the street for the compound you've chosen, you will need to switch to a less aggressive pad to keep them quiet...or learn to live with noisy pads.

I have Winmax W3 pads and they squeal like a mofo. I'm just living with until the end of the AutoX season. Will probably put the stock pads back on this winter.

my W5's actually don't squeal that much which is surprising.

I have Winmax W2's they squealed at first even with shims and with the brake grease. After about 2k miles later, they're completely silent and have great bite.