This post is to bring up the common 1.4T cracked turbo's relationship with max power tuning with the stock turbo. What are your experiences with this?
Working on optimizing my LUV again recently, I got meth installed and was trying to get boost above 20 across the rpm range. Boost is inconsistent and most often see about 21 psi peak, which falls to 16 psi by redline, but swear I have seen it hold more than this (same week, same road, similar conditions). I worked all the tables related to boost and parameters that would police the boost...but the telltale was the inconsistent DC % solenoid vs. boost/rpm.
I broke out the inspection camera, squeezed it in the down pipe O2 bung and found the infamous crack at the wastegate flapper.
Image on Google, not mine but basically it:
165714d1443495380-turbo-boost-problems-img_20150928_224119824_hdr.jpg
Before all this, I picked up a used JY 1.4 for cheap, the turbo is also cracked in same spot, some listings in car-part.com are upfront about the crack in addition I saw one cracked at 10k miles, ebay has plenty of cracked used turbos too. Internet searching makes it out to be a common thing.
The jist I got is, the crack does not effect stock performance (as far as maintaining desired boost), probably why no one is really warrantying them unless they get P-codes related to it. I've gotten the code last summer, but it never came back so I didn't think it was the issue. I still don't have the code.
I have visions of weld repairing the crack, unless there have been improvements to the design, I just haven't come across info on this yet.