Problem with a new header on a CRX

I agree with grippgoat that it may be a resonance problem. Long-primary 4-1 headers have a lower resonance frequency than do either short-primary 4-1 headers or the typical 4-2-1 headers. Try posting this on Endyne's board and see what light they can shed on this, he may be able to help you...

grippgoat:
If we remove the exhaust system, and just run the primaries, the same thing occurs.