I put a velocity stack on my Zenoah G-45 in an attempt to smooth out its response. No matter which direction I oriented it the result was inability to achieve more than 20-30% power even at full throttle. Took it back off and full throttle was no problem. Any recommendations?

Don

Re-set the needles. The mixture changes when ou add a stack.

The main thing is to make sure you do not use RAM air, i.e. do not have the slanted portion facing forward if the stack is cut at an angle. If the stack has been cut square across it, direction does not make a lot of difference but; if you have it under a cowl, you may inadvertently be getting some ram effect depending the how the air flows inside the cowl.

I mounted it both ways with the same effect. We also did fool with the mixture settings but probably not enough. Does the addition of the stack typically lean or richen the mixture? Which one?

Also, the stack sticks out of the cowl directly into the prop wash....

Hi!
90 degree to the prop wash???