Can a cracked header cause false and/or real KR???

[FTC]

well i was just wondering if a cracked header will cause knock weather it be false or real??? also does the lowest O2 reading always indicate when the car will knock??? cause my lowest O2 is at a lower MPH than my highest knock count MPH, if that makes any sense. does that mean its false knock??? its always below 3* about the middle of 3rd at 65-75 MPH. tia

 

[UNGN]

Originally posted by FTC
well i was just wondering if a cracked header will cause knock weather it be false or real??? also does the lowest O2 reading always indicate when the car will knock??? cause my lowest O2 is at a lower MPH than my highest knock count MPH, if that makes any sense. does that mean its false knock??? its always below 3* about the middle of 3rd at 65-75 MPH. tia

A cracked header will sooner cause real knock, as it will mess with the o2 numbers which will mess with your fueling, but I don't think thats your knock problem. (you need to fix it, though)

The lowest O2 does not always correspond with knock. You can have a low O2 and low load and it won't knock, or a higher O2 with a high load and it will.

Your Knock appears to be happening on the 2-3 shift. This can be false (downpipe hitting frame) or real (the extra load causes knock).

This is very easy to diagnose. If you get knock on the 2-3 shift, Buy one gallon of Race gas and pour it in. If the knock goes away or is reduced, it was real knock. If the knock stays the same, it is most likely false.