Would like to use a macs header pipe on my s3000. How do I get tank Pressure when using this muffler.

You can get the pressure nipples at most any hobby shop or from places like tower. You just drill a hole in the muffler and screw it in. Some are self tapping and some you have to cut the threads yourself. Sometimes the muffler comes with the nipple in the box but not always. When I used slimline mufflers I had to keep the nipples on hand and install them myself so I started stocking them in my building box.

As well as the different thread sizes the nipple come in, there are also self tapping ones as well as ones that insert from inside the pipe and have a nut on the outside

Thanks W8YE. Are there any difference in engine performance between headers and box/ and or silent mufflers.

Thanks Gary for the help.
Macs headers has info on tuning your engine for their headers. I don’t like the idea of losing RPM on the last cut. Are there other ways to tune?

Then go with a real tuned pipe instead of a muffler type.

When you are setting up and cutting your header for your pipe, keep the pipe pushed up close to the header at the silicone connector. Then as you see you are getting too short for peak, just pull the pipe out a little in the silicone connector.

Single stage tuned pipes are used mainly for boats and all out speed planes. They have a sharp peak to their performance. The engine does not run better than with a regular muffler unless operated in this narrow peak range. Also these engines show the most improvement in power when operated at a higher rpm with a small prop.

On the other hand, the quiet pipes are sort of a two chamber design that exhibit a broader power band that work great for pattern airplanes.