Laggy S372XE Single Turbo Build

[Hknba]

Hi, i have a 335i Manual with a Speedtech Bottom Mount Kit.
The turbo is a Borg Warner S372XE with a 0.91A/R T4 Divided Housing.
The car has been fun to drive and really reliable but i am getting tired of the Turbo Lag. I hit full boost (30PSI) at 4800rpm.
I wanted to ask if my boost coming on that late is normal and if there is anything that can be done to decrease the Lag before going to a smaller Turbo.
I would also be interested in your opinions in general about the Logs and Dyno Charts i attached, because i bought the car already built and i would like to know if theres anything that should be changed or looked at.

Build details:
Speedtech Bottom Mount
Mahle Low Compression Pistons
FCP H Rods
BMP Port Injection 750cc
Walbro 450
Motiv Reflex+

Its my first post here so feel free to ask any questions, i would be happy to provide more info/details.

 

[ktb_e92]

Hitting 30psi at 4800rpm with that turbo / turbine housing size is actually pretty good, I wouldn't be concerned. Your tuner can always make any turbo spool up faster with some timing & fueling adjustments along with the boost ramping in earlier RPM's, but internal durability will become a concern at that point due to torque levels. Now, since you have upgraded pistons and rods, you'll definitely last longer than a stock motor if you want your tuner to make the boost set in a little sooner if possible, just be careful with how frequent you use the power around that area