2500€ isn't that bad, given that a fixed geometry racing turbo is more than twice that.marcush. wrote:.it reaches this temps at times.. ...joseff wrote:the "hotness" of the exhaust gas in question is said to be well over 1000deg C.
I cannot be entirely specific about this but 1000 is too high and if you look closely to the setup you will see there is a exhaustgas temperature probe at the entrance to the turbo just because of this.. and this will not last long at temps above 1050..the VTG turbos in porsche cost an arm and a leg each if you fancy to buy a set..i think around 2500€ each... and then they are adjusted by actuators(included in that price) .so you need for each VTG a PWM signal in and the unit feeds back a PWM signal.. and you need of course an electronic throttle control as well as VTG is not really the equivalent of a waste gate.. so the boost pressure is largely controlled by throttle . ..
I think on the Borgwarner-BWTS web site is something about VTG even in english and about the Porsche development to be seen..unfortunately the real details are not available on the web ..
With a turbine made out of Mar-M 247, a properly designed bearing housing and a high temperature material in the turbine housing a turbocharger can withstand 1050 degC under long durations. But a small decrease in maximum temperature usually have a big effect in expected lifetime. The IDM 5322 material used in F1 turbocharger turbines in the eighties could for instance handle a race (2h) at more than 1100 degC, but then the turbine would be scrap. At 970 degC it would survive 1000 hours.
Production car turbochargers tend to be more dependant on average conditions than the extremes. Cycling is also an important factor.
It's also quite rare to measure the exhaust temperature, most cars calculate it instead.
