Exhaust leak Options

[scorp28]

This may sound like a newbie question but could you all give me a list of all of the problems that you can think of that would be caused by a quite substantial exhaust leak where the DP and the flex section meet. I am trying to make sure I cover all my bases and trying to determine exactly how close my car is to being ready for SCDC to see if I am going to be able to make it.

Right now it doesn't idle at 4K consistantly anymore but I am having a tough time getting the idle high enough and consistant. It is very erratic everywhere between not high enough to run and about 2500 but usually it is below 600.

Any help on either topic or both would be great. Thanks

[The Iron Goat]

Aside from fumes in the car, the exhaust leak shouldn't really be a concern, although some may argue that the leak causes additional turbulence in the system, introducing a slight backpressure. But it shouldn't make a big difference unless you're on that "ragged edge" of performance.

As far as the idle is concerned, make sure your EGR valve is sealed, and preferably blocked off. This gave me a rash of crap for a while. Also, do a boost leak check and focus on the TB to head section to give you an idea of where it may be coming from. Granted, you're checking for boost leaks, but when the system is under vacuum, the air flows the opposite way, and that will raise your idle.