Speeding Up Physics

I'd like to reproduce a realistic bounce using the awesome Bullet physic engine & SIO2. Unfortunately I'm seeing what looks most like a slow motion bounce on the moon.

To get things looking better I has to tweak the paramers that render the sio2 physics as follows. My question is there a better what to speed up the rendering when the physics is accurate....?

// render the simulation physics.
float ballPhysicsTimeStep = kBallSpeed * (1.0f / sio2->_SIO2window->fps);
sio2PhysicRender( sio2->_SIO2physic, ballPhysicsTimeStep, 0 );


Cheers!
Matthew