Scraping sound only between 4000 and 4500 RPM

It's a 1995 Acura Integra LS with the B18B1 engine, when I'm driving and hit pretty much exactly 4000 RPM, I can hear a light scraping noise, sounds like two metal objects lightly rubbing at high speed. It ends when I drop back down below 4k or get past 4500 rpm the sound ends, and it doesn't fade in and out, it's a sudden start and stop with the sound. Do you guys have any ideas? Google thought it might be something in the exhaust rattling at a specific exhaust frequency, but I haven't been able to text yet.