compressor surge

Hello , i have heard many arguments on turbo compressor surge but one interesting thought "compressor surge on acceleration bad / compressor surge when letting off throttle ok" is this true ? read it in a comment from DARKSIDEDEVELOPMENTS a respected diesel tuning company from the uk who specialize in VAG TDIs

THOUGHTS??

we all know who darkside is. I for one am not going to debate with him or against what he says for reasons i do not want to say. You can message them directly. they are here on this forum.
Read up on all the data and experience and make up or own mind or take his word for it on the exact application they have this data for.
/thread

Well, seems that "surge" on the compressor side of the Turbo could only take place if there is exhaust surge on the Turbine side. So, the question would be what causes exhaust surge.

I see spiking of Turbo boost on acceleration occasionally, but I have never seen boost spiking on deceleration (letting off the throttle). The Compressor's out-put is directly related to the exhaust pressure and angle of the Vanes. Letting up on the accelerator pedal immediately results in the N75 releasing vacuum on the actuator thus changing the angle of the Vanes to reduce Turbine spin.

Obviously, unless that are some components malfunctioning, there shouldn't be any spiking.

Would be interesting to know what Darkside says causes "surge" or spiking.