TalkRotary

First of all I have an S4 TII and when I drive my car in first, second and third gear, I get this knock or pop coming from the rear when I first put it in gear and start to take off in each gear. My suspension is crap so could it just be my springs squatting and adjusting that would cause this noise? I also think it might be coming from the LSD, but I did a quick burn out and had two solid black marks (working lsd), so could it be the half-shafts or something?

Now for my next question, I have a weapon R intake with a custom adapter on the AFM. Well, when I installed it, I put everything back on and I noticed the vacuum hose coming off of the air bypass valve was not connected to anything and for the longest time I didn't know where it came off of. Well I found where to put it and before it was connected it I would experience a loud BOV type sound when off the throttle, now it is no longer making that sound. Could I have been experiencing a vacuum leak from this? I had drove the car for about a month with this hose disconnected and I felt that performance was lacking and I was idling at 1k or higher as where it used to idle at 750-800 before the intake. Now the car is back to normal idle, and I just wanted to know if there is any side effects to having this hose disconnected? Any help?

No7Yet

Your front differential mount is toast. Replace it soon, or it could potentially damage your diff, driveshaft and transmission. Until then, drive very carefully, try to avoid jerky throttle changes and make your starts very smooth.

About the second part, it sounds like someone disconnected the BOV outlet so it would sound "cool", but didn't attach a check valve - they only raised the idle so the car wouldn't die. Yes, it was a vacuum leak. Things are better now it most probably didn't do any damage.

Brandon