Hi, first of all i will explain as much as i can. I was out for a spirited drive in my 51 bugeye wrx on saturday. I hit a bump in the road and damaged the front splitter (tore it off). Since then every so often there seems to be a strange sound.
From inside the car it sounds like something clunking underneath, under boot type area. But when you open the window it sounds like something is draggin underneath, as if the exhaust was catching the road slightly.

This can happen in any gear, at any speed and in neutral. It can happen every few seconds for about ten minutes, or not at all for half hour / forty minutes??

Ive had it up on ramps and there is absolutely no sign of damage underneath, nothing hanging down.....

And we turned the wheels while it was on the ramps and couldnt replicate the noise?

Any advice greatly appreciated as I havent got a clue where to look now.

Thanks

 

Although not an impreza, i was out with a friend in his clio a year or so ago when the same thing happened. Hit a bump on the entrance to the 25 and not long after kept hearing a scraping noise and clonking. It was only when we were being overtaken by people carriers and everyone including the drivers were glued to the window pointing at maties car we decided to pull over but there was nothing so we carried on. After this pointing kept on while on the motorway and we could still hear the noise we pulled over again.

Turned out to be a section of fairing or bumper at the front that was broken and when driving the wind pushed it down to the road causing it to scrape, obviously this couldn't seen when stationary.

check underneath again for any body work cracks etc, if i remember it was a sheet of black plastic dirt shield that was the offending part.

@dam

 

thanks for the suggestion.
Finally found the problem and thankfully it was a free fix :-)

A chipping had got stuck between the rear of the disc and the metal case that surrounds the back of the disk. It was sat at the bottom of the case, so obviously only scraped when it was pulled back up around the disk.

Just glad it was nice and easy fix. But wonder how two garages failed to find it....