Paul, If you have it handy, how many holes are in the inner tube, and what size?? I realize it is probably not that important, but it just saves me trying to work out something I know nothing about. Now sending my tangential muffler back to plan exhaust which will give then the measurements so that the new pipes will fit exactly . Yes I have heard that too, but should be close enough and they can reuse a lot of the original fittings, so cost will be greatly reduced.

 Neil.

I am guessing but the first 1/3rd   on the inner pipe drill  three 1/4 inch dia holes every 2 inches.


Next 1/3 3/8 inch dia holes every 2 inches.


Last 1/3 1/2 inch dia holes every 2 inches.

This is based on a guesstimate of the pressures in the inner pipe.

Start about a foot back from the start of the outer pipe.

In theory this is a jet engine so It should develop a slight  amount of thrust.

Another way of using some of the vast amount of waste energy in the exhaust.


Paul Lamar