I'm trying to I.D. a strange sound coming from my car.

Its a 'humming' sound that matches engine speed. I recently swapped from LG4 to TPI and the sound remains the same before and after the swap.

The car has a new alternator, a different a/c compressor, a different water pump and a different power steering pump.

Its a manual tranny car (t-5) and I'm wondering if its the clutch (works ok)? Perhaps it has something to do with that 'valve' thing on the pass side exhaust manifold (headers/exhaust work to be done in near future).

Any thoughts on what it may be?

 

Where is the hum coming from (do you hear it more in the passanger compartment etc.). Best bet is a stethescope. That many things changed... too damn hard (well, easy) to guess. Does it change if the car is in different gears, clutch in, partially in, etc.?