I had an issue in my last drive (sweihan) with lead @Asif Hussainwhere my car started withloud exhaust leak noise along with loosing power as it wouldn’t go beyond 5k rpm.
Turns out that the catalytic convertor had broken substrate which created back pressure on engine forcing it to cut power ( smart engine!)
On researching, I found info on how straight pipe exhausts allow for more engine power while
1. Introducing backfire noise ( gunshot sound)
2. more pollution
https://mechanicbase.com/cars/straight-pipe-exhaust/
As an alternative ,its is also suggested to go for high flow cat from a reputable brand.
any insights into this Mod. @Frederic @Gaurav @Vanessa8580
FYI , I drive the 2014 3.8 LWB PAJERO with 160k on the run.