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A muffler includes an inner passage residing in an outer shell, and a stationary fan residing in the inner passage. The fan creates a vortex in a flow through the inner passage thus improving the flow and reducing the exhaust sound level. The inner passage includes an inner passage shell and the fan

A muffler includes an inner passage residing in an outer shell, and a stationary fan residing in the inner passage. The fan creates a vortex in a flow through the inner passage thus improving the flow and reducing the exhaust sound level. The inner passage includes an inner passage shell and the fan comprises vanes extending inward from the inner passage shell and turned at approximately a 45 degree angle to a centerline of the inner passage. Pinch zones at the entrance and exit from the inner passage further reduce the exhaust sound level. The inner passage shell is preferably a perforated inner passage shell, and a sound deadening material resides between perforated inner passage shell and the outer shell.

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I claim: 1. An engine muffler comprising: an outer shell; an inner passage residing inside the outer shell, the inner passage having an inner passage shell and a centerline, the inner passage comprising: an inlet portion for receiving an exhaust flow and including a first pinch zone having a reduce

I claim: 1. An engine muffler comprising: an outer shell; an inner passage residing inside the outer shell, the inner passage having an inner passage shell and a centerline, the inner passage comprising: an inlet portion for receiving an exhaust flow and including a first pinch zone having a reduced first diameter; and a center portion following the inlet portion and having an increased second diameter greater than the first diameter of the first pinch zone; and a stationary fan residing inside the center portion, the fan comprising overlapping vanes angled relative to the centerline of the inner passage and attached to the inner passage shell and extending inwardly substantially reaching the centerline. 2. The muffler of claim 1, wherein the inner passage shell is a perforated inner passage shell. 3. The muffler of claim 2, wherein a space between the inner passage shell and the outer shell is filled with a sound deadening material. 4. The muffler of claim 1, wherein the inner passage is effectively unobstructed except for the fan. 5. The muffler of claim 1, further including an outlet portion following the center portion and including a second pinch zone having a reduced third diameter smaller than the second diameter. 6. The muffler of claim 1, wherein the vanes are angled at between approximately 15 degrees and approximately 75 degrees from the centerline. 7. The muffler of claim 6, wherein the vanes are angled at approximately 45 degrees from the centerline. 8. The muffler of claim 1, wherein the vanes comprise flat "D" shaped vanes. 9. The muffler of claim 1, wherein the vanes comprise between three and twelve vanes. 10. The muffler of claim 9, wherein the vanes comprise six vanes. 11. The muffler of claim 9, wherein the vanes comprise one of three and four vanes for less back pressure on a turbocharged motor. 12. The muffler of claim 1, wherein the vanes are welded together proximal to the centerline. 13. An engine muffler comprising: an outer shell; a muffler inlet having an inlet diameter; a muffler outlet having an outlet diameter; an inner passage residing inside the outer shell, the inner passage having a perforated inner passage shell and a centerline, the inner passage comprising: an inlet portion receiving an exhaust flow from the muffler inlet and including a first pinch zone having a reduced first diameter smaller than the inlet diameter; a center portion following the inlet portion and having an increased second diameter greater than the first diameter of the first pinch zone; and an outlet portion following the center portion and including a second pinch zone having a reduced third diameter smaller than the second diameter of the center portion and smaller than the outlet diameter; a space between the inner passage shell and the outer shell; sound deadening material residing in the space; and a stationary fan residing inside the inner passage, the fan comprising vanes angled at between approximately 30 degrees and approximately 60 degrees relative to the centerline of the inner passage, the vanes attached to the inner passage shell, and the vanes extending inwardly substantially reaching the centerline. 14. The muffler of claim 13, wherein the vanes are turned at approximately 45 degrees from the centerline. 15. The muffler of claim 14, wherein vanes comprise flat "D" shaped vanes. 16. The muffler of claim 15, wherein vanes comprise four "D" shaped vanes. 17. The muffler of claim 13, wherein a first pinch zone resides at an inlet to the inner passage and a second pinch zone resides at an outlet to the inner passage. 18. An engine muffler comprising: an outer shell; a muffler inlet having an inlet diameter; a muffler outlet having an outlet diameter; an inner passage residing inside the outer shell, the inner passage receiving an exhaust flow from the muffler inlet and passing the exhaust flow to the muffler outlet, and having a perforated inner passage shell and a centerline, the inner passage including; a cylindrical center portion residing in the inner passage and having a center diameter greater than the inlet diameter and greater than the outlet diameter; and a pinch zone residing after the center portion and having a smaller diameter smaller than the outlet diameter; a space between the inner passage shell and the outer shell; sound deadening material residing in the space; and a stationary fan residing inside the center portion, the fan comprising between four and six flat "D" shaped vanes angled at between approximately 30 degrees and approximately 60 degrees relative to the centerline of the inner passage, the vanes passing individually through slots cut in the inner passage shell and individually attached to the inner passage shell at the slots, and the vanes extending inwardly substantially reaching the centerline, wherein the inner passage is effectively unobstructed except for the fan. 19. The muffler of claim 18, wherein vanes comprise four flat "D" shaped vanes. 20. The muffler of claim 18, wherein the vanes are selected from the group consisting of vanes detached from one another and vanes welded together proximal to the centerline.