Quote:
Originally Posted by pengyou
I have been reading older threads and wanted to bring up what seems a contradiction. The thread claimed that max mpg happened at 200-300 rpm after maximum torque. Another thread stated that running a diesel at/above maximum torque shortens the life of the diesel. Can anyone comment on this? Also, does adding a second turbo to a diesel push the rpm at maximum torque down - lower rpms - or raise it?
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I can answer the bit about the turbo ...
Adding a second would have very little effect on either the power or the torque. It might affect how quickly the engine responds, a little.
Turbos add pressure. The engine doesn't care whether that pressure comes from one turbo, or six, all it sees is a pressure increase on the intake. However, smaller turbos react more quickly and can be cheaper, so it might respond more quickly (at a price).
You can alter the boost pressure from a turbo, which adds horsepower at the expense of reliability and longevity.
I'm sure there are other, minor effects, but that's the basics.
A bigger intercooler could possibly have a greater effect than more pressure.