legacycentral bbs

yesterday i was doing a hard run ( about 120mph) and i started going up a large hill. this meant that my turbo was working its hardest. i was running 15psi and then i lost boost really quick , and went totally down to 0. i pulled over cuz i thought i had blown off a hose. i thoroughly checked my set up and there werent any leaks or blown off pipes. now there is a really open sound to the boost ( like theres a lot of air going through, but not making pressure). recently i had changed my bov set up. i am using the stock bypass valve and my aftermarket bov as a sort of dual vent thingy. it was working great up to this point. it idled right, got better gas mileage and still had a little of the bov sound. i thought this strange set up was what was wrong with my car, but i changed it back to plain atmos. then to bypass, and i still got the same problem. i havent changed my boost controller which is set at 15 psi and it wont read anymore than 5psi. the acceleration sucks now, and since i dont have any boost leaks im assuming i have a dead turbo. does this assumption sound correct?

If I were you I'd first double-check all the intercooler and BOV plumbing. It really really sounds like a boost leak. Also look closely at the end tanks of the intercooler -- the plastic tanks do sometimes come apart at the kinds of pressures you're subjecting them to. And you might want to try one run with the BOV removed (cap off the fittings, turn the boost all the way down, and be careful not to slam the throttle shut).

Pushing 15 psi after a Saab 900 intercooler is asking a lot of the stock turbo... But I'd think if the turbo had given up you'd hear the bearings complaining loudly. If your turbo's okay you might want to reconsider your chosen MBC setting.

it seems to me someting is wrong with boost control if you only seeing 5psi. thats down by wastegate pressue

It doesn't sound like a bad turbo but like a boost leak. If it was the turbo you should get a metal on metal grinding sound. Unless it was seized but if it was you would not get 5psi you would get none.
Recheck the piping and IC.

I concur, it really sounds like a severe boost leak. I would really take another close look at your plumbing.

Like everyone's already said, I'd check for a boost leak. I'd check the bypass valve setup, followed by the intercooler and hoses.

I'm pretty sure you'd know if your turbo went up.

hey try resetting your computer by unhooking the battery for half an hour. My legacy used to shut down into "limbo mode" where it would run 5psi, this was atributed to the knock sensor. The factory ecu in my leg couldn't handle running more than 16psi either and would cut out when overboosting, hope this helps