RE: Super Tigre Blue Head Schneurle .40
Hey Dave.
I've tested a GS 45 with an old no name tuned pipe and gained 500 RPM.
It's very easy to test a pipe on that engine on the test bench, because you just have to take of the muffler and put a 15 cm long peace of silicone tube on. No need to buy a manifold for the test. Let the pipe go straight out from the engine and fix it, so it's possible to move it towards the engine when you tune it.
The set up of the pipe is similar to the picture.
I’ve bought a OS super silence muffler VERY cheap and removed all the stuff inside and enlarged the exit hole to 7,5 mm. The RPM’s are the same and the muffler is 35 grams lighter than the stock muffler (the muffler you have). Because of that I could take off 15 grams in the tail of the plane.
A downside is that you will have to modify the exhaust screw holes on the engine.
Good luck