Equipment of good quality and good looking, the cheapest market, but is not satisfactory: it is impossible to increase the diameter of a cold steel exhaust pipe. By replacing the O-rings with metallic rods, by heating the tube with a small torch I obtained a slightly conical increase of a few tenths of a millimeter at the inlet of the tube (I used the average tool). I think it is necessary to heat the tube "red" on a 100 mm long with a small forge to get a result. Soon, I built a small forge with an old cast iron grill to validate my solution.
