912iS increased to 105hp?

The 912iS was originally introduced with a smaller plastic airbox and intake runners.  This version produced 100HP.  With fixed pitch propellers it proved difficult to match for props so an update was made available and production changed to what we call the SPORT version 912iS.  This can be seen with the metal airbox and increased runner sizes of the manifolds.  This gave us an extra 5 hp in mid range and was much easier to match for fixed pitch props.  The mid range power increase was enough that they have to also change the overload clutch so they would not slip on starting.  (from 500 NM up to 600 NM) So in answer to your question the SPORT engine specs show the mid range increase and they just did not finish the curve on the peak values so they did not have to change the data or advertising.  My views anyway. 

Cheers

So the sport engine with the metal airbox is actually 105hp? How come the POH doesn’t indicate that? Did Rotax not decide until more recently that the 912iS Sport makes 105hp? This was the first I heard of that. Does this mean my 2013 built 912iS Sport makes 105hp?

Agree with above comments.....

I took the torque curves Rotax published for the 912uls and 912iS and multiplied by rpm which gave me the result that the standard 912 is about 97-98 Hp and the IS 102-105 HP,

However the graph line is pretty broad so some "interpretation" is needed....The result is that they are both 100hp...any difference is minor and academic !

QNH makes a bigger difference Today I was surprised to be flying with a QNH of 1035 (30.5 inches) about that makes a difference of a couple of Hp too !