exhaust diagnostic question (restriction?)

[DavidT]

welp... I finally got the 2 bolts at the ypipe and catback OFF. (impact air wrench couldn't do it, so I resorted to kicking the arm of the socket with my foot thumbs_u ... it worked!) Now what? I remember Scott P. saying to put a leaf blower up to it to HEAR if there is restriction. I did it but not sure what I need to listen for. Also, I am going to test drive it (with it disconnected). What should I expect in performance (if it is restricted vs. if it is NOT restricted)?
My whole purpose is to see why she doesn't run like she can.
It is now catless (temporarily). I noticed NO sound OR performance changes when they were removed This is why I am checking for further restriction. Thanks.

 

[sdpatt]

If you reduce the flow by restricting the outlet of a centrifugal pump (the fan in the leaf blower), you will hear the pump increase its speed because it is flowing less mass and working less. If the pipes are free flowing and you funnel (with tape or a tight fit) all of the output from the blower into them, you should not hear the pitch of the blower change much at all. If the blower sounds like you just covered its outlet with your hand, your pipes are very restrictive.

 

[DavidT]

OK, but we are talking about, what, 10 foot of exhaust pipe? Wouldn't it have to be stopped up in the first 3-4 feet to hear the restriction? Shining a flashlight in, it looks clear for the first couple of feet.