Boost Control on Restricted inlet

In many racing series yoy have restritor in inlet of turbocharger, lets say 32,34,45mm. I am curious how do you tune the boost regulation on it. My idea was try to find the correct spot in the Compressor map. Its very coplex i think, because the compresions ratio is changing not only by the boost level, but mainly because of vacuum before turbo. Lest say you dont have any restrictions and you want to run 2Atm absolute presure (200kPa) so you have CR 2:1, but once you have only 0,5Atm before the turbo (after restrictor) you may end with 4:1 CR and you may land in surge area.

Are my ideas correct ? And is it even possible to tune boost control on ECU that does not make any calculation between inlet and outlet pressure of an turbocharger ?

Any suggestions ? Thank you

There was a good thread on this awhile ago:

https://www.hpacademy.com/forum/general-tuning-discussion/show/turbo-wrestrictor-tuning-strategies

Also, Webinar 107 is on Analysing Turbo Performance:

https://www.hpacademy.com/previous-webinars/107-analysing-turbo-performance/

Thank you David, i have seen this webinar already....

I think in steady state, its pretty clear, i will just find the "sweat spot" and achieve the max power at lowest bost. The question is, what happens on situation after quick TP opening, when the Turbo sucks air, and builds a lot of vacuum to build some boost.... i am bit scary if the turbo goes trough the surge area or not, and how to control it.

In my own experience tuning restricted rally cars, surge really isn't an issue as you're unlikely to be able to drive the turbo hard enough to produce a pressure ratio that will run you into surge. In the higher rpm ranges where the restrictor is seriously hampering inlet flow into the turbo you will find that if request maximum duty cycle from your boost solenoid that the boost pressure is severely limited which in turn limits the pressure ratio. You'll actually find though that at high rpm you'll make more power if you bring the boost down slightly from the maximum pressure you can actually achieve.

Thats enough explaining, thank you Andre