Ok, im working on my buddy's 87 supra. I just replaced the turbo with another CT26 and everytime we start to build boost, it engine cuts out at around 5 psi or so of boost. I think it might be a severe boost leak, but all the pipes are in good shape. I think it might be the blow off valve for the fact that when i first got the new turbo hooked up, the BOV sounded like it normally did (the fluttering noise), but I turned up the boost a bit with the XS manual boost controller and it popped one of the intercooler pipes off and now sounds more like a semi's. I put the pipe back on and now it's cutting out.