710n and n75j fitted = resonance

[chrisa4quat]

after fitting my n75j and 710n, i am haveing a vibration/resonance noise, sounds like my car is breaking wind, happens about 2500-3500 rpm, has anyone had this problem, could the valves be fitted incorrectly, the car is running better than ever!

 

[PhilR]

Mine does this on slight throttle at the same rev range, i have an adjustable wastegate actuator and the spring i have in it is too stong i need to change it , so i have put the noise down the the car not been able to regulate boost properly as the spring wont allow the actuator to open at all untill after 9psi so pressure is building in the intake system, that allied with the slight vacuum being applied to the 710n on partial throttle is causing it to open slightly and bleed back into the air filter making a brrrrrrr noise.

I would check all your pipes, make sure you have the n75 the right way round ( which is different orientation to the original) check that the pipe to the actuator is on and not nipped.