Turbo tb 45 compression

[nissannewby]

Is decompressing the way to go? To me that's just offsetting the turbo so why not just turn down turbo?
Could it be more timing or Fuel mixture?

On a petrol it is, it's already on the low side for that setup boost wise. He could get the tune looked at and make sure its nothing simple like timing. If it hasn't had the compression lowered then what they do is basically start to diesel (compression ignition) so it's already starting to ignite before its even sparked.