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, Tue, 26 Mar 2002 17:57:33
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Hi !
Because of our ideas of how a turbocharged engine should work, the turbine pressure is a bit high.
But because we have "excellent control" of the engine running condition we can do this.
It is easier to use a bigger turbin, since this will reduce the turbine pressure, but it will also move the boost threshold to higher revs.
As a general rule of thumb, I´ll guess that you can say that there is a 1:1 turbinepreeure to compressorpressure ratio at max power.
But it doesn´t have to be like this.
It can be better or worse.
High turbine pressure is not good for the turbine shaft seal, and normally it´s the same as high exhaust temperature.
Remember that the pressure and temperature difference is what powers your turbine.
If, exhaust(system) backpressure can be reduced, then that results in lower turbinepressure.
To give you the same turbinepower.
The Garrett T25 is not the very best choice for hi-output applications, as you mention, it´s a bit too small.
But, some crazy guys claims that they have reached 260 bhp or more.
Yea, sure, but I do not like the idea.
It is a question of what concept you are using.
I prefer a solid concept, where you can floor the pedal for quite some time without beeing scared to death that something will break.
Typical exhaustsystem bckpressure can vary alot, but let´s say, 40-60 kPa.
Maybe half of that can be found in the catalytic converter.
So, it is not only the diameter of your exh system that is imortant, but also the shape of the system.
Bends, joints and so on, can give you some unwanted backpressure.
The shape of turbine exit is important.
Well, there are a lot of things that are important, just now I will get on my bicycle and go home, and make some food !
"To Be Continued"
posted by 192.85....
, Tue, 26 Mar 2002 17:57:33, Wed, 27 Mar 2002 17:40:09, Wed, 27 Mar 2002 20:51:07, Wed, 27 Mar 2002 20:11:37
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