Vacuum tees
Here are descriptions of the hardware we will use in most of our custom hotrodding creations. These items are actually pretty common; you just need to know what to look for. I intend to add pictures to this page as soon as I can to further help you find the things you'll need.
This one is a no-brainer. You can find bulk vacuum line at any auto parts store. You can use those nylon lines which the factory gave us in conjunction with the rubber line; however the rubber line is much more durable. (The hard nylon gets very brittle with age.)
Vacuum tees are small plastic connectors with three ends. They are usually in the shape of a letter T (hence the name) but can also be found resembling a letter Y or F. No difference. Look carefully when shopping for tees; some of them will have all three barbs of equal diameter while others may have barbs of different diameters. Be sure to get the correct tee for your specific application. These are common at larger auto parts stores; you may also find them in many hardware stores and even lawn and garden places (look in the section for very small lawn sprinklers).
A restrictor is a simple vacuum connector with one twist: inside the connector is a brass insert with a small hole in it. The purpose of a restrictor is to delay the time required for vacuum (or boost) to travel through the connector. Why would you want to do this? In our case it helps speed turbo response. By now you've probably noticed that when you floor it the maximum boost level goes high and then settles back down to the preset level. This overshoot is called the boost spike. You can directly control the size of the boost spike by using a larger or smaller orifice in the restrictor: the bigger the restrictor's hole, the smaller the spike; the smaller the hole, the bigger the spike.
Also known as a needle valve, a bleed valve can be anything from a cheap (some less than $1) plastic aquarium valve up to $20 precision brass item. They all work and which one you use is up to you. A bleed valve is used to bleed off pressure--think of it as a very small controlled leak. Where can you buy these valves? Large hardware stores are the best place since they tend to have very sturdy brass units. If you strike out in your area, you may have another unlikely source: pet stores. It may sound odd, but aquarium supplies can also work. (Ask for gang valves and they'll point you to the right aisle.) These units are made of plastic, however, and their adjustability typically isn't as smooth as the brass units... so I mention them only as a last resort.
How does a bleed increase your performance? Easy--it directly determines what level of boost is generated in your intake manifold. Our cars run a vacuum/pressure "feed line" from the intake to the wastegate actuator. If you were to run full boost pressure to the actuator, your boost would always stay low (about 7 psi max) because this pressure would blow open the wastegate and prevent higher boost levels. Your car's stock computer raises the boost above this minimum by "bleeding" some of the air pressure out of this feed line through the opening and closing of the wastegate solenoid; cycling the solenoid reduces the amount of boost pressure in the feed line which then reduces the opening of the wastegate. If you manually bleed more air out of the feed line than the computer does, your boost level will go higher than the computer lets it go. That's all there is to it.
A check valve is the air equivalent of a diode--they only let air pass through in one direction. I have found small plastic ones in the aquarium section of pet stores in my area; you may also find them at most auto part stores and sometimes at large hardware stores.
A solenoid simply directs air (vacuum or boost) from one tube to another. These are very common in cars. They are used by Dodge, Chev, Ford, and more; they're found in cars with and without turbos. Most of these solenoids have 3 hose-barbs sticking out of them; that's the kind you want. You can always blow through one barb; we call this the center barb. When the solenoid is off, the air you blow into the center barb will flow out one of the end barbs--this is called the off barb. When you apply 12 volts to the solenoid's 2 wires (it doesn't matter which wire is negative or positive), the air you're blowing into the center barb will now come out the other end barb--the on barb.
Having trouble finding a solenoid to use? I always grab mine out of junkyard cars. One nice bonus when you acquire one in this manner is that each solenoid comes with its own nifty mounting bracket--it makes installation a snap.
Modified 9/14/07.