I just wanted to make people aware of the master cylinders that are supplied with a couple of companies brake booster delete kits. These kits usually include an adapter plate, a master cylinder, and a clevis. It seems that the popular master cylinder that is supplies with these kits (jhp USA and map performance) is the single outlet wilwood compact master cylinder. This master cylinder is incorrectly applied for cars with 4 wheel disc brakes. Not only is is incorrectly applied, but it is dangerously, possibly even lethally applied. When using a single outlet master, if a failure occurs anywhere in the brake system that causes a loss of pressure, the entire system will lose pressure. I found this out after purchasing the jhp kit and contacting wilwood directly with a question. They are the ones who informed me that it is strongly recommended to not use this master with disc brakes and that they had intended this master for use on some of their pedal kits. I then contacted jhp to inform them of what I was told by wilwood and they pretty much told me that they don’t really care. They then lied and said that they intended it for cars with drums, even tho the cars on the application list include cars with only 4 wheel discs(dc integras and s2k) as well as cars ghat had trim packages that included 4 wheel discs. Once again, this is info directly from wilwood, the manufacturer of the master cylinder so don’t try to argue this information. With 4 wheel disc brakes you always want to use a tandem, or dual outlet master cylinder.

 

Why would a single outlet MC only matter with discs and not drums in the rear?

 

I have no idea

 

I may be wrong, but I believe the original design and use of these booster delete kits was for drag racing and staging brakes, not for street use. I'm also guessing that many of the companies selling these kits are doing so because they want to offer something the people will buy and don't have any clue as to what the original intent was or research to know what they are selling. Take a look around different website and read what they say in the booster delete descriptions. Some say for show cars, almost all use that common CYA disclaimer that these are for off road use only, so they can't get sued when Jimmy slams his ricer into the rear end of the Mercedes at the first stop light he comes to. There is even one popular brand name that refutes the single outlet design as being unsafe, but, they just came out with a $600 kit that includes a custom dual piston/dual outlet master cylinder and a mounting bracket that mounts the master 1" higher and an adapter to move the pushrod from the brake pedal an equal 1" higher, resulting in a better ratio. Maybe they came up with this on their own, or maybe they copied someone else that did it several years ago. They also mention that it's now race ready and will pass inspection because of the dual outlets and separated reservoir, which is true, but it's required by the race organizations because it's safe. Everyone gets to make their own choice on how to mod their cars. Read and try to find others that have done the mods you are thinking about to get real world experience on what works and what doesn't. It's been said, especially in the car mod business, that you don't hear about the failures of some products because the people that chose them died in a car crash...