View Single Post
      07-08-2021, 04:19 AM   #129
05cobra
New Member
14
Rep
11
Posts

Drives: bmw x5 m50i and bmw x3 m40i
Join Date: Dec 2020
Location: NSW

iTrader: (0)

Quote:
Originally Posted by speedyman View Post
What is OPF? Same as GPF? I guess I am the only person here who does not know 150 of these damn acronyms.
I believe the OPF is the same as what you're calling a GPF @[speedyman]

On a side note, I had a Catback system installed on my X5 with a H pipe. I have 2 mufflers (1 into 2) on each side and kept the factory valves. I'm currently experiencing horrible drone between 1100-1600 rpm with even partial throttle applications.

Also, I personally feel like the valves aren't doing much at all - I can't feel any airflow changes between sport and comfort by putting my hand next to the tail pipe.

Does anyone know what might help reduce that drone down? It's difficult to drive the car now

Also - the exhaust isn't that loud even with the new system if anyone was interested. My X3 M40i (2019) had a louder cold start.
Appreciate 0