Dear AndréD,

Hope you're well. As you do your own repairs - and can weld - I offer another suggestion. As the difference between EGR and non-EGR catalytic converters (cats) may turn on flow-rate - and no one seems to know what, if any, difference there may be between EGR and non-EGR units - why not install a cat made for a turbo?

A cat made for a turbo will certainly have an adequate flow-rate. The only "wrinkle": a turbo cat's intake and outflow pipe diameter will be wider than that for a non-turbo car. Therefore, you'll need to use short sections of pipe to build-up the in-place pipes, to the diameter of the cat's pipes.

Making "collars" to build-up the in-place pipes should not be very hard. An exhaust pipe expander should be adequate to the purpose.

The only folks, who can explain why there's a difference between EGR and non-EGR cats are Volvo's engineers. They'll simply tell you to buy the part your car requires, as cats have no user-serviceable parts inside. Thus, even if you knew - to fine detail - what were the differences, that info would be of little use, as the after-market makers either won't divulge their data, or do not have any data to divulge.

Hope this helps.

Yours faithfully,

Spook