The TaG engine war is all but over. Most series are now going to a spec-engine, single engine formula for simplicity’s sake.
Back when the TaG concept was formed, the Rotax Max engine was doing very well as an electric-start touch-and-go engine. Other manufacturers were hoping to capitalize on this formula and create their own version. TaG came from some folks saying, hey all these engines are similar, let’s group them and even out the performance by changing ballast and weight limits per engine and let them race together. Since none of these engines were built to the same spec, they all have very different powerbands, resulting in each engine excelling at different tracks. The Rotax, with it’s mid-range power would really smoke the other engines on a mid-range track that was very flowing with no tight corners or long straights. The Leopard had lots of bottom and top end so on a track like New Castle it drove away from the Rotax. This eventually ended up with everyone competing on a national level to have several engine types, one for every kind of track, which was pretty costly to the racers, who were getting a little fed up with it.
The cool thing about the class, at that time, was that it catered to so many different racers. Big guys could throw a powerful Sonik engine on and would have to make a 380 weight limit while us little guys could run Leopard at 365 and everyone races together. The bad part was that it was almost impossible to achieve parity across the engines through each event. It was to the point where the race schedule would dictate what engine you would run for the year, unless you could afford one of each engine.
Because of that, as well as engine companies handing out lucrative sponsorship packages to series, the major organizations have decided a single-engine formula is better for TaG, so you’ll find each major series is mostly now catering to one TaG engine package.