Wastegate, where the hell is it and what can i do with it?! [Archive] - SaabCentral Forums

: Wastegate, where the hell is it and what can i do with it?!


90t16Saero
11-03-02, 05:45 PM
Where the hell is my wastegate and can i adjust it safely without damage to the engine to give me more boost? A picture and an A-Z route guide would help me thinks!

Janne Selinummi
12-03-02, 03:14 AM
The wastegate is located below the turbocharger. If you want more boost, adjusting the wastegate actuator will give you some, but you will kill the protecting capabilities of the APC system. I wouldn't recommend that. In a 900 Turbo, the easy and safe way of increasing boost is to modify your APC box. For that stuff you will find many topics on the forum. APCs can be modded to allow much more boost than original, while the knock sensing feature stays intact.
IMHO, this is the way to go.

me0u021e
12-03-02, 09:09 AM
Right, wastegates are a crazy, yet potentially power enhancing things. They cut off the boost, well limit it, when you get too much. Normally these run with a little pipe from the inlet and open up the gate when boost pressure is reached. Slight problem with this, boost fluctuation. Its best to run it so boost is defined by exhaust pressure. Takes alot more setting up but the potential is amazing! For more info email me on me0u021e@liv.ac.uk and I'll post you the info on how to do it.

Viktor
13-03-02, 12:00 AM
Janne,

Why/how would the Wastegate adjustment kill the protecting abilities of the apc?

Janne Selinummi
14-03-02, 05:52 AM
If you shorten your wastegate actuator arm (as it's usually done), the APC will still work, but it will be lowering the boost much less than the system is supposed to. When the arm is shorter, the wastegate opens later and thus the car runs with more boost.
Doesn't this also increase the basic boost?
This all means that the APC function is less effective, and if you increase the boost by shortening the arm in pursuit to any real hp gain, the APC function is going to be substantially weaker.

87SPGIN
07-04-02, 10:30 PM
what about the performance actuators that essetnially produce the same effect but are brand new and you get them from like a performance site?Those also limit the possibilities of the APC

Johann F
08-04-02, 05:02 AM
Not exactly - the problem with shortening the stock arm to raise pressure is that when the APC need's to bleed boost the arm cannot move far enough to let enough pressure escape and you can get overshoot (spikes of pressure which can hit the overboost switch) and boost creep (the total inability of the APC to reduce pressure). What an aftermarket actuator has is a stronger spring which opens at a higher pressure - but it opens all the way to allow proper pressure control.