So I'm coming up on one year after I redid my heads, for the most part everything is perfect. One of the problems I've been having is the fact that I can't manage to keep exhaust hangers intact. I've run my side dump straight pipe for about 5 years without a single issue and since I put everything back together I busted 3 hangers in about 3 months. So now I'm just running a downpipe with nothing behind it. Recently I noticed that she's running a little low on boost. Right after I did the rebuild I would regularly get 38psi under hard acceleration according to the ISSPRO gauge (I don't trust the factory lie-o-meter), now I can't even get 30 on a good day. I'm almost 100% positive that I don't have a leak because I don't know of any boot or crack that would release 10psi and not blow apart. I also feel that the turbo is still in good shape because there is no play in the shaft or impeller, not to mention I don't know of a failing turbo that can still get 25+. The only thing that has changed since my nice high numbers and now is that the exhaust is off and I can't even peg it on that because I can't pinpoint if it started when I pulled the pipe. Yes, the turbo was cleaned when I had it out during the rebuild. Could this be the cause? It's the only thing I can think of.

 

Had sort of the same issue recently, pulling 5th wheel toy hauler to Florida from Michigan. Pulling at about 2500 to 3000 rpm up hill good boost (25-35 psi), after going down hill, little or no boost. I would check your EGR sensor and pipe, it may be bad or restricted. Mine was.

 

So I got the exhaust back on, took it down to a local shop and they welded up 4 additional hangers, thing is SOLID. My boost hasn't returned to its "normal" range, it is in the stock range so maybe I'll try data logging it and send the file to IDP to see if there's an issue with the tune. The only other thing I can think of that changed was I put a BPD FICM in since I was getting dangerous voltage during cranking and while running the volts would drop into the 46-47V range. I set the computer to the stock tune before I did the teardown just in case something decided to tweak during the process, but once I got everything back together, did the run in to burp the oil and cooling systems, played musical injectors, fixed a coolant drip and then put the new FICM in, I set it back to my street tune, I was seeing my usual 35-38psi boost readings. I don't know, maybe I should stick with 30psi since the truck still does everything I need it to and be happy before I blow the tanks off the intercooler.