Wastegate Bleeder T mod

Purpose: To create more boost than stock (11psi). With this mod on a stock Supra, expect about 15-17 psi of boost, which is about 60-70 HP!

Note: do the BCC before doing this mod to prevent fuel cut!

Parts Required: two 1/4"x1/4"x1/4" vacuum Ts (available at auto parts stores), knife, 2" long 1/4" diameter hose (optional).

Time Required: 5 minutes.

How it Works: By bleeding off air from the actuator, the wastegate stays closed longer, which builds more boost than stock.

Disclaimer: This modification puts additional stress on the turbos, clutch, transmission, etc. These components may wear out prematurely. Obviously this modification will void your warranty (however, it is easily reversible). A boost gauge is essential to monitor boost levels. The general consensus is that you should not run more than around 18 psi on a regular basis.

Steps:

1. Locate the black, 6" hose that goes from the vsv to the brass actuator. Figure 1 shows the general location: front, left side of the engine bay, just above the alternator.

 

2. Figure 3 shows a close up. Cut hose 2 in half. Insert a vacuum T (fig. 2) into the two hose ends that were just created by cutting.

Note: there are two ways to insert the vacuum T:

As in fig. 4 (this is the classic method, creates approx. 15psi on a stock motor).

As in fig. 5 (this creates additional 1-2 psi of boost because most of the airflow coming out of the actuator goes straight thru the open end of the T). I recommend using a a Manual Boost Controller to limit boost if this method is used.

 

Note: An alternate/better way is to disconnect hose 2 from the actuator. Connect a 2" long, 1/4" diameter hose to the actuator. Connect hose 2 to this new 2" hose via the vacuum T. This method doesn't require cutting the factory hose, making it easier to put the car back to stock condition.

 

3. If desired, attach a 12' long 1/4" diameter hose to the open end of the T (as shown if fig. 3) and run hose into the cockpit (if desired). A simple valve can be attached to this hose that can be used as a Manual Boost Controller.

 

4. To gain approx. one more psi of boost, cut hose 1 in half and insert a T (fig. 6). Note that you can't use this in conjunction with the Manual Boost Controller unless you run another hose and valve off this T as well. On my car, I just keep the T on hose 1 capped unless I go to the drag strip.

Note: some people have found that 1/4" vacuum Ts aren't tight enough. If a hose blows off the T then use a 5/16" T instead, and/or consider using hose clamps.

To create the maximum amount of boost (for the drag strip, etc.), simply disconnect hoses 1 and 2.

Fig. 1

 

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Comments/suggestions? Email me