wastegate

[bcl]

Guys,

A common technique is to increase the spring pressure in the wastegate diaphram when running higher boost pressure, rather than replacing the spring with a heavier tension spring (as I have in my car).

You can increase the spring pressure by effectively shortening the arm by the following methods:

1. bending the wastegate arm …. Very crude

2. cutting the arm, cutting off some of the length, then rewelding

3. use an adjustable arm (APS do this with their stage 3; refer to http://www.airpowersystems.com.au/falcon/actuator.htm )

The major disadvantage that I can see with the above is that you may restrict the total length of movement of the wastegate arm, so your wastegate swing valve may not open as far, possibly restricting wastegate flow (I have used methods 2 & 3 above in the past).

A better approach is to use a higher tensioned spring, if you can source one.

Brian

[igsta]

Bending the actuator arm was a mod done to alot of older turbos. It was a way of fooling the motor. On boost air passes the actuator so you dont over boost. By bending the arm the engine thinks it is boosting a certain psi but you actually get more boost through the turbo rather then the actuator. I think it is much better to fool the engine by using a bleed valve, where a small amount of escaping air from a hose going to the actuator, increases alot more psi. Both these mods cant be done to our T as the computer over rides this. Gone are the days where a bleed valve as little as $50 could give you an extra 20kw.

[slapnut]

igsta Posted on Apr 17 2004, 06:55 PM

  Bending the actuator arm was a mod done to alot of older turbos. It was a way of fooling the motor. On boost air passes the actuator so you dont over boost. By bending the arm the engine thinks it is boosting a certain psi but you actually get more boost through the turbo rather then the actuator. I think it is much better to fool the engine by using a bleed valve, where a small amount of escaping air from a hose going to the actuator, increases alot more psi. Both these mods cant be done to our T as the computer over rides this. Gone are the days where a bleed valve as little as $50 could give you an extra 20kw. 

I agree!

Bending anything on our beloved T's is sacrilege.

Sounds like a mod better suited to carby fed, non computerised, turbo cars..