These fan units do look somewhat the same. The quickest way to tell the difference is the Dynamax has an 11 blade impeller and the RamTec has 9 blades. The Ramtec is usually $10 or so less than the Dynamax. The Dynamax also has aluminum angle fan shroud mounts. The Dynamax is made by Jet Model Products in Missouri and the Ramtec hails from Australia. Both are quality units.

Generally, the Ramtec requires a bit more airflow through the intakes for top performance than the Dynamax does. I have used both and I liked both. I used the O.S. .91 on both of these fan units. I believe the Ramtec does not allow the O.S. .91 to rev up quite as high as the Dynamax does so one could reason that that is a benefit of the one over the other. Both units produce lots of power and a strong running fans.

To best answer which would be best on your sport jet, could you please share with us what sport jet you are speaking of.