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I just checked SKUSA’s online sheet of all TAG motors and their respective dyno’s. Very very interesting stuff
Parilla Leopard…..24.9 hp, 12.7 ft lb torque.
Rotax Max, 26.5hp, 14.0 lb ft torque, but has redline of only 12.5k rpm
Biland 250cc 25.8hp, 15.8 lb ft of torque
sonik made almost 27.5hp!, only 11.7 lb ft of torque. redline near 17kOverall, the Biland with those shear torque numbers, and similar Hp numbers makes me almost want to get that, for the fact you could put a ton of hours on it without a rebuild. It’s obvious why of the 2-strokes, the parilla is the most reliable. And because it’s stroke is only 50mm, the sonik by far outrevs them all.
(ROTAX, though, if you were allowed to play with the power valve, would probably beat them all. Anyone know why they only rev to 12.5k?)The Rotax will rev a bit more, it is rev limited to 13,500 by the ignition but you can get a bit more out of them if you do a good job of jetting and gearing. However, the power drops off the table after 12,500. That has to do with port timing and such. The reason the Rotax is limited is to increase motor life. The Rotax is rated for 50 hours where if you rev the other 2 cycles to the 16+ range they are capable of, you won’t see half that life.
On tracks where there is a longish straight and a very slow corner, the limited rpm range of the Rotax is at a clear disadvantage to the other engines. On a track like IMI where ther are no slow corners, the Rotax has an advantage as we can keep it in the sweet spot. If Brad were to take the hair pin and flaten it and a couple of others (they are all banked now) or even make one off camber, it would completely take away the Rotax advantage there.
The top 4 in TaG Senior this past weekend and the top 2 in masters were all Rotax.
That totally makes sense. I wondered why the Rotaxes kicked so much butt this weekend. Im curious why anyone doesnt make a motor with say a 58mm bore, and a 50mm stroke. Thing would rev like mad and have tons of torque.
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