Thanks man, where are you locatee?
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Right outside Nashville.Thanks man, where are you locatee?
Dave, thanks for the reply. I think I'll go with DOT 5.1 and track-specific pads before deflectors/hoses. Thanks!I'd look at 3 things related to braking for your next track day - 1) cooling for the brakes - maybe just "deflectors" instead of hoses, 2) fresh high-quality DOT4 or DOT5.1 (NOT DOT5) fluid with a high dry boiling point, and 3) brake pads with a higher working temperature than street pads.
Yes I am. My son was in Hendersonville and just bought a house in Portland.Right outside Nashville.
Edit: I suppose that's quite broad if you're familiar with the area. NE of Nashville, not far from KY state line.
Perfectly explained.There are really two very different kinds of brake fade, and you can tell which one you're suffering from by the symptoms.The DOT3, DOT4, and DOT5.1 ratings give regular people a general idea of brake fluid performance, but track enthusiasts should really look at the dry boiling points of the specific brake fluids they're considering using.
- Pad fade - The car doesn't slow down as fast as it should, but the brake pedal is still firm at the usual height. You have overheated the brake pad compound. Damage ranges from minimal where a "cool lap" can recover braking effectiveness (until you overheat them again), to severe where the structural integrity of the pad compound is compromised and the pad material "crumbles" off the backing plate. Solution is to use a pad material with higher heat tolerance and/or cool the rotors. Typically, compounds with higher heat tolerance perform worse at cold/ambient temperatures, so you end up changing between "street pads" and "track pads" for events. Depending on brand and compound, the two may not be compatible, requiring either cleaning & bedding of the rotors with each change, or dedicated rotors sets.
- Fluid fade - The car doesn't slow down as fast as it should, and the brake pedal is soft, spongy, and/or engages noticeably further in its travel (or "goes to the floor"). The brake fluid in the calipers has boiled, turning an incompressible fluid into a compressible vapor. The vapor will mostly condense on cooling, but the fluid will lose performance overall. Solutions are to make sure the brake fluid is fresh (brake fluid absorbs moisture from the air which reduces its boiling point - see dry vs "wet" boiling points in fluid specs), use fluid with a higher dry boiling point, and/or cool the brakes/calipers better. Also, you can insulate the caliper pistons and the fluid behind them from the heat of the rotor with things like titanium shims from site sponsor Optimum Performance, or using a thermal barrier coating on the pistons.
Great explanation DaveW. On second read through I agree with you he may have boiled the brakes. If he used a cheap Autozone DOT 4 with a lower boiling point or his system is still contaminated with DOT 3 and/or air, then this is the likely the case. However, a pad compound upgrade is a good idea regardless.There are really two very different kinds of brake fade, and you can tell which one you're suffering from by the symptoms.The DOT3, DOT4, and DOT5.1 ratings give regular people a general idea of brake fluid performance, but track enthusiasts should really look at the dry boiling points of the specific brake fluids they're considering using.
- Pad fade - The car doesn't slow down as fast as it should, but the brake pedal is still firm at the usual height. You have overheated the brake pad compound. Damage ranges from minimal where a "cool lap" can recover braking effectiveness (until you overheat them again), to severe where the structural integrity of the pad compound is compromised and the pad material "crumbles" off the backing plate. Solution is to use a pad material with higher heat tolerance and/or cool the rotors. Typically, compounds with higher heat tolerance perform worse at cold/ambient temperatures, so you end up changing between "street pads" and "track pads" for events. Depending on brand and compound, the two may not be compatible, requiring either cleaning & bedding of the rotors with each change, or dedicated rotors sets.
- Fluid fade - The car doesn't slow down as fast as it should, and the brake pedal is soft, spongy, and/or engages noticeably further in its travel (or "goes to the floor"). The brake fluid in the calipers has boiled, turning an incompressible fluid into a compressible vapor. The vapor will mostly condense on cooling, but the fluid will lose performance overall. Solutions are to make sure the brake fluid is fresh (brake fluid absorbs moisture from the air which reduces its boiling point - see dry vs "wet" boiling points in fluid specs), use fluid with a higher dry boiling point, and/or cool the brakes/calipers better. Also, you can insulate the caliper pistons and the fluid behind them from the heat of the rotor with things like titanium shims from site sponsor Optimum Performance, or using a thermal barrier coating on the pistons.