A few years ago I visited Chas Windridge of Mogsport fame to get some AVO shocks for my +4 T16, and he suggested that to get much better breathing I should remove the restrictor plate that's spot-welded about half way along the internal pipe of the silencer. (This plate has an approx 1/2inch hole in it, so reducing the effective diameter of the exhaust pipe considerably).
The method he suggested sounded rather brutal – knock seven bells out of it with a long, hefty steel bar – but I tried it, and it worked! It's made a big difference, too. The engine is much more willing to rev, and the exhaust note has a bit more of a burble. And all this for zero cost!
Makes you wonder just what a 'sports' silencer is, though...?
