Loud humming sound within first mile of first drive du jour
 

I drive my (Vitesse) 951 at minimum every third day, usually once per day.
On that initial drive of the day, after it's gone about 1/4 mile I've recently heard a loud continuous humming sound.
About 50% of the time if I quickly clutch down it will stop, the other 50% of the time I can cluth down and it won't matter.
It doesn't reoccur after I've gone about a mile and won't reoccur the rest of the day.
It doesn't affect the drive, any ideas what this could be?

My initial thought was the turbo water pump is getting noisy...but reading further makes me doubt that initial prognosis.

Can you provide more info on car and on the noise?
Specifics like recent service dates (clutch, trans, cvs etc) as well as your best guess on where the noise is coming from would help significantly.
Answers to questions like "RPM Specific?" "Speed Specific?" "Straight or turning?" and things like that will also seriously help narrow down the possibilities of what it might be.

Ethan

My fuel pump used to do that sometimes, mostly when it's really hot out.

Best guess is middle-bottom of the car.
RPMs <=3500 since I don't up the RPMS until the car is at operating temp.
Speed is <=35 mph since I'm making my way out of the 'hood towards the highway.
Always straight.

This is from the service log I keep, this started roughly around the time the Dealer performed the alignment on 9/23:
10/31/2014 174000 Transmission fluid change Mobil1-75W-90
9/23/2014 174000 Removed uncabled parking brake on passenger's side
9/23/2014 174000 4 wheel alignment Dealer
9/15/2014 174000 Short Shift kit only944
9/15/2014 174000 Changed both front lower control arms and (Weltmeister) bushings 944online
8/15/2014 174000 Oil change, lucas oil stabilizer Dealer
8/6/2014 173000 Fuel injector cleaner Lucas
8/6/2014 173000 Tail light seals
8/6/2014 173000 A/C recharge, selant
8/6/2014 173000 Temperature sensor, wire, water temp gauge Autometer

The sound comes on irrepsective of temperature and cuts off within a mile. The only thing that makes it stop (aside from time) is taking out of gear. Not letting off the gas and not pushing in the clutch ... doesn't affect performance, just want to make sure it's not indicative of anything serious

I let the car warm up for 10-15 minutes until the water temperature is between 160 and 180F before I take off. The humming sound doesn't occur when I do that

if taking it out of gear stops sound while holding RPM constant, I'd drain and refill the trans and look at the fluid - metal particles in the fluid suggest a bearing having issues. if it's coming from the middle of the car, a failing torque tube bearing may be indicated.