Low turbo boost
 

1988 turbo supra. Seems like I'm not getting the turbo boost I should.
When it kicks in the gauge goes to about +1 max. (no boost at -4, needle only will reach +1 when floored) This stock gauge of course goes to +8.

I found cracks in the turbo inlet pipe. Replaced with nice steel one and put on a K&N filter kit. All other in/out hoses seem in good shape.

What could be the problem?

Fuck that stock gauge. It's inaccurate and unreliable at best.

Go buy yourself a quality (about $50) mechanical boost gauge. That is a gauge that has no sending unit, you just connect a vacuum line straight to the back of the gauge.

If you still only register 1psi with a mechanical gauge, and you say you have no vacuum/boost leaks, then your turbo might be shiting a brick in the near future.