by Warkton Tornado No.1 » Sat Oct 09, 2021 12:10 pm
Not tried any exhaust with small tailpipes on any of my engine builds of over 200cc with performance enhancements since the 1970's, except on track. I made an exhaust that was fantastic with it's torque on tight, twisty tracks for a Group Four. But it was dire on faster tracks as it wouldn't allow over rev @ places like Cadwell Park. That was 7/8" (22 mm) bore.
It seems that some exhaust manufacturers are now cottoning on to the fact that small tailpipes will create issues, notably: loss of power due to 'back up', heat build up, resistance to rev, lack of over-rev etc.
That's the risk you face. A replacement tailpipe of one inch bore will transform it, but you'll likely need to add a supplementary silencer.....