| Re: Turbocharger efficency
And I thought I would keep it simple!!
You have studied well Adam. The isentropic efficiency of good turbos does not change a lot from manufacturer to manufacturer and it is all academic in the event that the turbo is too large or too small for the engine. The other problem is they operate in less than ideal conditions, have a constantly changing speed of rotation and variable ambient temperatures. I am fortunate enough to have had my own Dyno for some 30 yrs and have played around with forced induction for a similar period. I have done pages and pages of calcs and then when you run the engine the results are not the same as calculated, more often not even close. I have found that paying a lot of attention in getting the free air into the turbo reaps huge benefits ( isentropic efficiency goes up)as does getting the exhaust to the turbo. To just consider the isentropic properties alone will not necessarily give a good result. These days the turbo manufacturers can give you reasonably accurate figures of what you can expect for the correct engine/turbo match.
Trevor |