So, I'm in the middle of replacing my catalytic converter and now I can see the inside of the turbo, I can spin the flapper too easily - it clearly isn't sitting snug. The actuator arm has very little play but it's not holding the flapper shut as I believe it should. I think that the actuator arm needs adjusting to take up the slack and hence, seal to allow boost.

My catalytic converter has been giving blocked symptoms for a couple of years and I just ran with it, eventually I started getting turbo boost codes and presumed it was the blocked cat. Performance had also dropped to the extent that I had little - car was very sluggish. I did boost checks by pressurizing the system and never found any leaks. Now I can actually see inside the turbo I think the problem has always been down to a poorly sealing flapper.

Whilst I have the car stripped this far, I'm thinking of taking the exhaust manifold off so that I can get to the actuator adjusting nuts and set the flapper shut - what do I have to loose if the turbo is on its way out anyway?. I have read alot about pre-loading the actuator arm and people seem to go for setting the flapper closed then adding 3 full turns on the nut. I'm thinking initially to set it to maybe 1 turn at most as I don't want to push it.

Any advice from you guys?

 

wear on flapper seat.

photo of the blocked cat....

after adjustment ...

before adjustment made.....
Update: I removed the exhaust manifold to allow me to have access to the adjusting nuts, initially I removed the front nut, this allowed me to move the flapper and check its seating. As one of the photos shows, there is wear/pitting and possibly some of the seating missing - clearly an issue that will not allow perfect sealing. I cleaned up the seating as best I could and adjusted the actuator enough to hold the flapper closed, the amount of adjustment I made was approx two threads as can be seen by comparing the before and after photos. This means that when closed (at rest) the flapper no longer spins so I should see some improvement in boost.

Hope this diagnosis and the photos help someone out there

I have no doubt that this turbo is on borrowed time so I will be looking for options - since this is an old car I don't want to spend much money so, any suggestions?

 

Update: Ok, so all is well, new cat and adjustment of wastegate actuator arm seem good. Car has much more performance and does have a slightly 'throatier' ring to it - definitely not loud and tacky though, more of a tuned ring to it

You guys are real quiet on this site now.... is anybody out there?


There was no holding clip so I improvised....

New cat going in...

 

I see people are reading this post so here's an update:

Car is running way better than ever, I always thought the sluggishness of the car was due to a combination of a small engine, auto box and the heavy quattro. Clearly from day one of owning the car, that flapper wasn't sealing properly meaning I've always been loosing boost! Over the years the flapper seal area has gradually worn because of this as you can see on one of the photos. Simply adjusting the flapper to fit snug and fitting a new higher flow cat has given the car a new lease of life. It really is quite nippy now!

I just hope the flapper seal on the Turbo doesn't wear any further and I can get some more mileage out of it before replacing...

 

Thanks, helps alot I'm going to try this , I feel like my car was slow af , going to like tops 90mph , I took off my turbo today and the nuts holding the arm were gone , but noe adding the nuts lid feels loose ima tighten up and put the turbo back in see if it helps .

 

If there were no nuts on there then you must have had virtually no boost at all.....

I think there should also be a clip holding the nuts on and to stop them loosening, if your nuts were lost then you wont have the clip either. Make sure you secure them by either 'double nutting' or what I did - tie stainless steel wire around them as my photo shows. I used aircraft grade security wire - you can get it cheaply on Amazon.

My fix is still working great by the way - car is way better!