Loud Knocking noise recorded at high speeds - Help needed please

[Arjuanamo]

I was coming back from Stansted the other day on the M11 and the roads were empty . Once i reached a pretty high speed i noticed this loud knocking vibrating sound that seemed to be coming in front and below from me . It disappeared once i dropped the speed slightly and then reappeared as soon as i went up in speed again . I have gone above this speed numerous times in my life and have never noticed it before .

During the last week i has my Bilstein B-12 kit fitted and rang the garage who installed it . They told me it was unlikely that changing the suspension would cause a noise that is quite central in the car . I have uploaded a audio clip of the noise . it disappears in the middle as i drop the speed and then reappears when i reach the speed again .

Any advice would be great before i go to a garage to investigate further.

 

[Sayam]

Botton engine cover flapping because it hasn't been inserted/screwed to the front bumper properly?

 

[audismart]

Botton engine cover flapping because it hasn't been inserted/screwed to the front bumper properly?

Same.
It sounds like a flapping sound, not a knocking noise.

 

[Arjuanamo]

Thanks for the input. I will take it back to elite direct as they are the only people who have worked with my car so maybe they loosened something by mistake.

Sorry for my inaccurate description too


Sent from my iPad using Tapatalk

 

[Sayam]

Park 2 wheels on the kerb and get underneath, you'll be able to tell straight away.