Pe or Dar,

I have aquired a NIB MVVS .61 engine less exhaust.

What is the performance & RPM difference in the 3250 long pipe assembly verses the 3253 short pipe assembly??

I see that Pe has them both in stock & want to order the best choice.

Thanks, Mike

Mike,


The RPM difference on the same size prop, with the pipe adjusted to the optimum length would be 300-400 RPM.

This might seem like a small difference to you, but in HP terms this is ~9-12%, which are substantial.


This engine is designed to be at its best around 11K RPM and at optimum length, with the #3250 pipe it would spin an APC 13x8/13x9 prop around 10,800 RPM.


For an F3A flying style the full length pipe would be an excellent choice, but for optimum transition and response, the #3253 tuned silencer is a better choice for 3D style and sport flying.

We have used this engine on a 4-star with the 3253 short pipe and 14x7 prop. Running 9600 rpm static, this was a very dependable combo with some power to spare.

Thanks guys,

I appreciate the fast response.

Mike