Quote:
Originally Posted by sw20kosh
It is the same phenomenon as:
A. 9:1 CR 2.0L 26psi =400 hp
B. 12.5:1 CR 2.0L 14 psi = 400 hp
Going back to the supercharger in question... not every engine processes the airflow of the supercharger the same. One engine can be hyper efficient at producing power with the same air flow. Upping the CR is increasing the efficiency of the motor.
The 300 hp rating they give that unit is a bit misleading because it does not account for the efficiency of the motor it is being installed on.
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So let's agree on the basics: an internal combustion motor is basically an air pump. If you push more air in the front, the more will be flowing in the rear. If you restrict the amount of air in the front, efficiency will go down.
So if you put a supercharger or turbocharger in front of the air pump that LIMITS the amount of air the pump and ingest, then the pump can only do as much work as the amount of air the supercharger or turbocharger can provide.
You CAN go slightly beyond the supercharger/turbocharger rating by running super cool fuel, like e85. But NOT 100% over. There just isn't that kind of headroom in fuel and the cooling properties and knock resistance properties it conveys.
Going back to that compression ratio example you give: if both motors have a 10lb/min turbocharger installed on it, then the BEST case is that you get 100hp. It doesn't matter what size or compression ratio or kind or anything else motor it may be. BECAUSE you are *limiting* the amount of air it ingests.
budi