jordanL2

Hello, I知 in desperate need of pointers. I have a 01 A4 1.8t manual with a k04. I swapped my turbo out last week because my old K04 had a bad waste gate and I had a spare laying around. I知 now having an issue where my boost will build to 10psi and immediately lose boost and drop to 0psi, then build back to 5psi and drop to 3psi and it値l bounce between 3psi and 7psi while I have my foot at 60%-100% throttle. I can hear the woosh from the diverter valve and watch the boost drop while my foot is on the gas. At one point it spiked to 25psi in 3rd gear when I floored it from low rpm. It seems to build and hold boost better when I floor it from low rpm whereas if I floor it in a higher rpm it won稚 build any and it goes nowhere. Rpm climbs extremely slow. It値l only hold boost a couple seconds before blowing it off. No CEL either!

so far I swapped out the n75 valve from my other car, made no difference at all. I unplugged maf, did a smoke test on the vac lines and found a small leak from the TIP which I fixed. I reseated all lines and checked over everything multiple times.

I should note, the K04 that was in the car was a k04-015x which is slightly bigger than the XS-Power K04-15 I put in it, and the previous owner did a hack job and hollowed out the turbo inlet to make it bigger to fit over the bigger k04. So im not sure if there痴 possible leaks present only when there痴 load. I知 out of ideas and patience, just looking for some pointers at what I should look for. Thanks in advance!

jordanL2

Here is a video of my boost gauge while accelerating

https://streamable.com/16gfek