Hi guys, I got a strange (loud rumbling, exhhaust system banging against the undercarriage) type of noise while driving in the rain the past two days. I sounds so loud as if you didn't have a muffler. You only hear it if there is at least 1-2 inches of water on the road, speed can be anything north of 25mph. The only mod is a cobb tuning exhaust.

Once you are aout of the standing water, no more loud exhaust droning and rattling.

I had the same noise on my Integra with a Greddy exhaust, a few years ago.

Any ideas as to what is causing this? Thanks.