Thread: turbo or super
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Old 03-02-2021, 05:37 PM   #23
Irace86.2.0
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Quote:
Originally Posted by mrg666 View Post
That only happens after a downshift without pushing the throttle. It is a useful *feature*, done on purpose for engine brake or entering a curve with high rev while aiming to exit accelerating. If sc is over-spinning continuously at constant speed, there is something wrong with either the valve spring adjustment or the driver is not shifting right.
You completely missed the context of the conversation. We were discussing the use of the bypass valve as a wastegate to bleed boost like turbos bleed exhaust, so someone could run a smaller pulley, but not hit high boost. Essentially they would bleed boost so boost would be flat instead of building with rpms. I was saying this means that if the supercharger is hitting 10 psi from 4-8k then it is spinning twice as much at 8k than at 4k while only producing 10 psi, so at 8k the engine is working harder creating more heat and is less efficient than it is at 4k. It is over-spinning while the bypass valve is open and bleeding/wasting boost. Turbos don’t waste boost, which is why they are much more efficient when doing boost-by-rpm/gear/map.
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