Ok didnt know that.. What boost controller??

Mike

 

I hope you are right Mike! I have a feeling it is just something simple like that.

 

I believe its just a gm bcs. Not 100% sure.

 

Im curious if anyone with a AMS 850r turbo kit is experiencing any similar issues at low boost.

 

on a bench with compressed air? you can't use that as an accurate test of when it will open because there is no force on the valve head itself

 

+1, and I have also heard of the 38mm creating some boost creep. I'm just curious why you wouldn't want to go to a 44mm or larger WG. And you said you had a GM boost controller? I couldn't tell... and what kind of data are you logging to see boost and other areas that may help you isolate?

 

Yes, this is the method we used. You are correct but i thought it would give us some sort of idea of what spring I was using.

 

I don't have an issue with going to a bigger WG, other than the fact that I will have to remove the turbo kit again and have a bigger flange welded to accept the 44.

I don't understand why AMS would use a 38mm if it was so prone to boost creep. Guess its just to cut cost.

To be honest, Im not sure what data was logged, but Im sure it was done correctly, and if it could have been tuned out, it would have been.

 

I would honestly go with a 44mm wastegate or bigger but 44mm will do.

 

Maybe switching to an .82 housing would help

 

If you bypass the boost controller and just run a line from the comp cover to the wg, what does the boost curve look like?

My 35r setup, recuiced wg, pte 5 bolt, 38mm tial gate off the turbin housing would hold ~23psi to redline. For a referance point.

Fathouse

 

I would honestly recommend a larger WG, but that would really depend on your specific goals.

I don't think anyone needs to know who tuned your car (cause for debate), but knowing specifically what they are logging to help fix issue would be important, so some tuners may not have the knowledge to track down a potential or existing problem...

And going to a larger hotside may help a lil, but again, what are your goals? I totally understand going with a .63 vs .82 because I would want the power sooner than later.. Im not a top speed guy, so going bigger in that respect wouldn't be important for me...

I'm still stuck on your Boost controller though... I personally like an EBC rather than stock ECU controlling my boost. The GM solenoid works, but I like the ability to change my boost levels on the fly, and it definitely keeps boost in check..

good luck

 

We did not try this but its definitely worth a shot. Thanks.

 

Precision does not make a 5 bolt .82 backhousing for this turbo, as I am pretty sure this would help to eliminate my problem if I could get one.

 

Is there an adapter to bolt up a 44mm to 38mm flange? I really dont want to take the turbo back off again, if at possible, to weld a new flange on.

Yeah I have chosen not to throw my tuner out there but he is a well known tuner and Im pretty confident he knows what he is doing. He has mentioned everything you guys have brought to my attention so I think we're on the right path.

A bigger hotside is not available for this turbo, in a 5 bolt.

I have definitely been meaning to grab a deacent boost controller. Its being controlled by AEM though, not stock ecu.