Flat four?

[SPman]

I've just fitted a Motad 4-2 collector on the old XJR 13. Now, it sounds like a VW Kombi (or Subaru WRX if you have pretensions....). Fair enough, it's not that bad actually, and according to others, the Motad collector does this, but, Why?

[Taz]

It just does.

[Latte]

so there...

[steve_t]

The boxer burble is most pronounced when you have unequal length headers

[Jay GTI]

Wot he said...

Down the the header length and the point (timing) of when the exhaust gas pulses reach the end of the exhaust. Modern WRXs (and most other Scooby boxers) use equal length headers and sound much more like an inline 4 these days.