05 Outback xt overboost issues, already tried known remedies

[05unicornXT]

Hello all, I am new to this forum site but I do know I am suppose to do searches before beginning a new thread. I have done that. You guys have all been an extremely valuable resource for me over the past two months while I have been battling my outback. I have gotten to the point where I no longer know what to do. So here is a overview of my issues. Any advice or pointers of where to look next is greatly appreciated.

 

Stock turbo failed, you all know the story...... In order to just return my car to the road so I can continue working on my autocross car I bought a turbo off eBay. Im not proud of it. I just didnt see alot of good options right now. i didnt have the money for a nice aftermarket one, and finding a used one for the outback XT proved impossible. At any rate that is what I bought. In addition to the new turbo, I installed and Invidia uppipe, Invidia downpipe, and a 3 inch full exhaust. I also installed the upgraded oil feed line kit from IAG performance. Those are the only mods on the vehicle.

 

When I drove the car after replacing all that, I didnt know it at the time but it was over boosting. It ended up exploding the inter cooler off the car and breaking it. I dug around and found that the wastegate could not function properly because of the divider in the new dowpipe. Pulled that off and ground it out. solved that problem, can now move the wastegate freely. Drove the vehicle again, still overboosting, blew the intercooler off again. So now I am an idiot for not hooking up a boost guage. (I just thought for sure I had the problem fixed). Now I have a boost guage hooked up just so I can better test. I read about the restrictor pill that is in the vacuum line on the turbo. So I grabbed that off my old turbo and put it on there. test drove again. ran anywhere between 15-18 psi. Sometimes even spiked up to 20 psi. So then I tried taking the boost control solenoid out of the equation. I capped the lines instead of having them go to that. I had pretty similar results. I read on here that stock boost should be around 13.5psi. So I am still overboosting. Another issue is it seems to be terribly inconsistent. Sometimes it doesn't seem to spike too high, but every once in a while it will. It is tough though because I am trying to be careful I dont want to wreck anything else.

Tonight I am going to try putting my OEM wastegate on the new turbo. That would be just about the only other thing I can think of to try. I will let you guys know the results.

But if you guys have any other suggestions on things I could check, I would greatly appreciate the help. And I know alot of people are just going to want to say well you shouldnt have bought a cheap turbo!! And I understand that. Im not normally a person that cheaps out. It just came at a bad time. I bought the car a month or so ago. Flew from wisconsin to texas to get a rust free one. Had the timing idler go out and belt skip time basically a week after I got home. Got that all back together and then the turbo blew. So I am just a bit in over my head right now with this car. So forgive me on the cheap turbo. I understand that this could indeed be my issue. Im just wondering if there are other things that I could try before condemning this turbo. Thank you all for the help and advice. Sorry for the long write up.

[bigleben]

You can't just install new parts and be done with it ...

 

Your ECU still thinks it has stock exhaust with more restriction so stop doing pulls with it and put your XT on the dyno or contact a tuning vendor to get set up correctly!

 

Is your ebay turbo a cheap OEM turbo or a cheap Aftermarket unit (16/18/20g/etc) ??

 

I advise you to stop going into boost until your tuned for your setup otherwise you might need an engine sooner then later.

[05unicornXT]

The turbo is just the OEM replacement turbo. I had thought that even though I replaced the exhaust components with less restrictive the wastegate spring should still regulate the boost when I have the electronic part of it taken out of the equation shouldnt it? Because that part of the system is mechanical. Vacuum line running directly from compressor housing to the wastegate. Or does this wastegate function differently than some that I was accustom to? I for sure hear what your saying about having it tuned to account for the different exhaust components. I will be doing that for sure. But even a tune wont be able to stop that from overboosting unless I am really mistaken on how that system works. I read another thread on here explaining that the boost control solenoid is normally closed. It would only open if the computer wanted more boost pressure. It would open and bleed pressure away from the wastegate, therefore allowing the turbo to boost more.

I am not stating these things as facts. This is simply what I had thought I gathered from different sources. Please let me know if I am nuts in how I am thinking this process out. Again thank you for the help, I really appreciate it!

[Max Capacity]

http://people.csail.mit.edu/ilh/vacation/

 

Your going to want to look in the back of the 05 service manual and see how the turbo vacuum lines run.

 

Get the car on a Cobb AP or open source tune before you hurt the engine.

 

You've come to the right place these cars, read the sticky's at the top of the forums and learn.

 

Don't know where you live but I'd suggest you buy the Cobb from www.tuningalliance.com and it may come with some benefits. He's one of the best if not the best Tuner for these cars. Yea, he is that great.