Quote:
Originally Posted by volkdent
Is there any reason to go with an external wastegate vs. an internal(turbo housing)? I'm trying to keep it simple, and I can't for the life of me figure out out if the external is necessary for my project.
Jason
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Well, the really large turbo's usually don't come internal, but there are advantages if you do have a choise. Most of them are for turbo nutcases only probably, but an external gate has its own exhaust and therefore does not hinder the exit of the turbine wheel. Keeping back pressure close to zero on the downpipe (turbo exhaust side) is what this does and that is crucial to a good turbo efficiency. A little more power can be had by this.
There is also the better boost control if you have a relatively large turbo and run low-ish boost. Internal gates can be somewhat small-ish and boost creep can happen then. External gate usually flow more and don;t experience boost creep.
Thirdly you can rotate the turbine housing more freely (in all positions, 'clocking' the turbo) if you don't have the arm of the internal gate to consider, which is usually attached to the compressor housing. That makes it easier to position the turbo any way you like wrt inlet and outlet openings
