broken belt tensioner

[pae9132]

I have tried a search but couldn't find an answer to my question. I have a 2003 automatic G35 sedan. I had an UR under drive pulley set installed yesterday and today my car broke the "belt tensioner". That's what the mechanic called it. I also have headers, catback exhaust, hyper GT grounding kit, kinetix intake plenum, and a stillen intake w/z tube. Would the increased torque cause this to brake? My car is all motor. When my pulleys were put on I also had new belts installed. I was told that the new belts might need to be broken in more before I start driving spiritedly. I am spending over $500 today on the tensioner, and fan assembly which was busted by the tensioner pulley when it broke off plus maintenance fees. So basically my question is if I can keep the new pulleys on without worry of breaking another tensioner? Thanks for the help.

[Q451990]

This is a new one to me. Maybe the belt was massively overtightened? Hopefully someone else will have some insight here.

Heath