SAAB Secret: Retrieve Lost Turbo Pressure for FREE in Less Than a Minute
This trick comes from Chris 9-5, a moderator on the SaabCentral forums. It was in a thread from July of 2007. I found it while searching for Forge diverter valve information. The OP had posted about weak turbo pressure and Chris 9-5 suggested the following modification:
Remove the top vacuum tube from the boost control valve and then plug the loose tube.
Chris 9-5 explains that it bypasses a one way valve that can become faulty.
It worked wonders for the OP. Chris 9-5 recommended that only people with weak turbo symptoms should make this modification.
As far as I knew I didn’t have any problems, the car drove as spirited as the day I purchased it. I had all the power I needed, the car was quick… so I naturally decided it wouldn’t hurt anything to try this trick.
The results were dramatic! It is like driving a different car. My whole driving experience is totally enhanced. The most noticeable change is when the transmission kicks down at wide open throttle on the highway. I really feel the torque steer for the first time, just like the OP in the thread described.
Here is how I plugged the vacuum line; I found a bolt that was the right diameter and cut it down to about an inch long. I then painted the head to make it look nicer. It’s that easy.
Some people in the thread didn’t see a difference when they removed their line. Other people tried it and found the change remarkable. The people who have made this modification haven’t seen any problems and I will make a post if I see any negative results on my 9-5. I’d say people should give this a try and see if they get back some turbo pressure. Just revert it back if there wasn’t a positive change in performance.
Whoa! I’m getting anywhere from 2-3 more PSI. I can get it up to 9 PSI in third gear. I haven’t had room to give fourth a real workout yet. It definitely pulls harder in every gear though. So where was this boost before and why was I not getting it? Does that mean the BPC valve is bad?
I’ve read that it is caused by a failure of a one-way valve on the EVAP system. I tried finding a replacement valve and it seems it can’t be purchased separately from the $300 set of EVAP hoses. So if you want a million dollar idea, find a cheap replacement for that one-way valve and 9-5 owners everywhere will beat a path to your door.
Where is this located on the 3.0t?
I’m not finding a listing for a Boost Control Valve on the 3.0 in the parts catalogs. That turbo setup on the V6 is unique enough that I don’t have a clue how it works, to tell you the truth. I know the turbo and the manifold are basically one piece and the pressure from the turbo is only fed to three of the cylinders. It must have some other method for controlling pressure.