Here's my situation.
Car: 2005 Wrx STi
Modifications: Cobb stage 1 93 Octane
As we all know the STi comes factory with 14.5psi, and we also all know that Cobb Stage 1 increases this number to 16.5psi (+/- .5). My car is currently making 8.8 max psi. First thing that came to mind was boost leak, so today i ordered a boost pressure tester to perform a test. BUT....if i had a leak then the MAF would not catch it, therefore, I would be running rich, which i find i AM NOT, after reading my A/F Ratio's at idle and WOT. So i do some more thinking/researching and come across some info about my car coming factory with a manual boost controller. Basically the wastegate valve is opened some for less boost and closed some for more boost and when the wastegate actuator is fully open, the vehicle will run mechanical boost pressure which can be anything from 7-11psi. So i put 2&2 together, I'm not running rich so it couldnt be a leak, and im making 8.8 max psi with the correct fuel consumption, as if the wastegate was opened by the previous owner of the car, explaining how it could run so low of boost and the ECU correctly respond. BUT ONE PROBLEM.... all IHI turbochargers have a fixed wastegate actuator rod that cannot be adjusted. Meaning the previous owner could not have "manually" opened the wastegate to make it run mechanical boost at 8.8psi.
So this leads me to ask a few more questions....
1. Does the Wrx OR STi come with the factory manual boost controller? OR both?
2. If so, then why do i see alot of ppl on the site (Wrx & STi owners) attempting to buy aftermarket manual boost controllers?
3. Are STi owners buying aftermarket manual boost controllers to compensate for the fixed wastegate actuator rod?
4. If an STi has a manual boost controller from the factory, why does it not have an adjustable wastegate rod?
5. Does the wastegate need to be adjusted via Engine Management if it has a fixed wastegate actuator rod?
Im still going to run the leak test when my pressure tester comes in, although im confident this is not my problem.
If the leak test results show no leak, then the only thing i can think of would be to purchase an adjustable wastegate, if possible.
First i want to state the fact that earlier i mentioned that my car was not running rich. So i went out and ran it again watching my a/f ratio's, boost, etc... and cruising my ratio's are looking good at high 14's, but when WOT my ratio is at 11.1. This could be a LITTLE on the rich side, but i think the Cobb stage1 causes this 11.1 ratio.
So this brings 2 current outcomes to the table
1. I do have a boost leak, and when im at WOT it begins loosing pressure and therefore giving me the slightly rich 11.1 ratio.
2. It is the Cobb stage 1 map giving me the ratio, and im back to wastegate possibilities.
I would also like to add the fact that when in Neutral im reading anywheres from 10-11psi, and like i said earlier 8.8psi when WOT; Reading from the A/P live data screen.
Once again, any takers?