No - this is not standard business practice. I have used ANSYS for quite a while and have never seen or heard of gouging like this. I suggest to explain that you can take your next contract elsewhere. ANSYS is well-liked for certain reasons (not important here) but you can always go to NASTRAN.
I love this stuff... in this area (or just about any non-linear acoustics area there is nice, easy, simple thoery and then you have reality. The combination of effects from tubing geometry to exit conditions, inconsistent combustion processes, etc. all add up to one terribly complex set of...
The University of Michigan (Assanis), among others, (check SAE) has done some fine work in this and related areas... and I can say that one has to understand the "system" as opposed to just a single component. My opinion is that unless an entire system solution is followed...
KIVA is free... but your time is not. What do you want to model? IC engine simulation is a broad subject. KIVA can only really do a small portion of what constitutes a cycle.
