Rotax-– Rotax 912; 80 – 100 + HP and the 914 turbo 115 + HP engines offer a wide range of exhaust options. We have dual muffler systems, single muffler systems, and single muffler with tight cowled aircraft. Most exhaust systems start with a PVC mock up kit (See mock up kits). This is done to get the exact exhaust system you want.