randy merritt
Donating Member
With the cam I have, I only have about 10-12 inches of vac at idle. I have good brakes, but the lack of vac doesn't let them preform to their full potential. I also was looking for a way to be able to do a hard boost launch without having to go through the rev in neutral procedure. It would also be nice to be able to stage the truck at the drag strip without having to pull up to the line, rev in neutral, etc. I also have no interest in going through the hassle and expense of installing Hydroboost.
I decided to try a stand alone vac pump and separate the brake booster to manifold connection.
I bought a Hella UP30 rotary vac pump from summit (apparently they come as factory equipment on some Subarus), and made a rough bracket to mount the pump near the brake booster:
I bought a vac switch from summit also. I was trying to figure out the best way to install it, as it needs a check valve on the pump side of the switch in order to work properly. It turns out that the switch fits perfectly in an existing threaded hole that is in a vac canister that I had laying around. Using this canister also allowed me to use a standard booster check valve.
I wired the vac switch (which is normally closed) as a ground trigger to a relay that then powers the pump. The brakes feel much better now, and I can do a hard boost launch without having to rev the motor in order to build vac. The system pulls about 22 inches of vac, which is a lot better than I had before. The pump is very quiet, and you can not hear it running with the engine running. I powered the relay with a key on 12V so the pump will not run without the key on.
Couple of installed pics.
I decided to try a stand alone vac pump and separate the brake booster to manifold connection.
I bought a Hella UP30 rotary vac pump from summit (apparently they come as factory equipment on some Subarus), and made a rough bracket to mount the pump near the brake booster:
I bought a vac switch from summit also. I was trying to figure out the best way to install it, as it needs a check valve on the pump side of the switch in order to work properly. It turns out that the switch fits perfectly in an existing threaded hole that is in a vac canister that I had laying around. Using this canister also allowed me to use a standard booster check valve.
I wired the vac switch (which is normally closed) as a ground trigger to a relay that then powers the pump. The brakes feel much better now, and I can do a hard boost launch without having to rev the motor in order to build vac. The system pulls about 22 inches of vac, which is a lot better than I had before. The pump is very quiet, and you can not hear it running with the engine running. I powered the relay with a key on 12V so the pump will not run without the key on.
Couple of installed pics.
