[Aussie Mike]

Hi Peter and welcome to the forum.

Is your car injected? Are you running the pump in the tank? What was your fuel level like?

I've found with some regular (non Cobra) cars I've had with in tank fuel pumps that the lower the fuel level gets the louder the pump gets. With the tank in the Cobra being right behind you and the 3/4 empty tank acting like a sounding board it can get quite loud. Also as you are cornering and accelerating the pump isn't always covered by the sound deadening fuel so you get more noise. When you stoped and then re started all the sloshing fuel settled down and the pump was submerged again keeping it quiet.

I guess if you think of it how an acoustic guitar works. If you twang a guitar string in the free air it doesn't make much noise but if you put a hollow box behind it it pumps the volume up dramatically.

The other noise I've noticed that becomes more aparent is the fuel return line squirting fuel back into the tank. As the fuel level drops this seems to make more noise too.

It's just a theory and I could easily be wrong. It would be interesting to try it again with a full tank.

Cheers