The blower is making what sounds to be a front bearing noise. It only happens when the trans is in Drive or Reverse and the L isn't moving Like foot on brake at a light). The RPM's are low (like 750 or so). If I start to coast or put it in Neutral, the revs raise a little and the blower stops making noise. (I know, increase the idle and it won't happen anymore)

I put a 4# lower pulley on about a month ago. Upper pulley has never been off. Has anybody had problems like this before??? Lightning is an ' 01.

Mods are 4#, chip, TB, VB, cold air, stock exhaust 12.89@107.8 on F1's

 

I remember someone saying that the blower at idle is cavitating. It's not really cavitation, it's just running in a higher vacuum than normal.

https://www.f150online.com/forums/sh...threadid=86958

 

Cavitation?! The prop on my boat cavitates when the drive is up too far and is caused by the water boiling on the prop. I don't think so in this case. Plus, it only happens at idle.

 

Have your chip reburned, the blower's cavitating (sp?) which can be solved by an idle adjustment. Call whoever burned your chip.

 

Hmmm....check out this thread....

https://www.f150online.com/forums/sh...threadid=58984

 

My truck has done the same thing since I installed a 4# pulley, its nothing to worry about, your just hearing the super charger a little more because its spinning faster.

Larry.

 

Crazy (Loco), thanks for the link. There are so many ideas on that thread about what may be happening. I am not entirely convinced that any one of them is correct, but a few seem logical.

Sal's view seems like it may be the closest to what is happening. The vibration and rumbling kills me dead every time I hear/feel it. Really does sound like bad bearings or bearings not getting oil or something (Which I know is not the case).

 

This 'might' help....................

http://198.65.157.241/forums/showthr...=pulley+grease

Dan

 

Thanks Dan. I just had a client in my office who happens to be a gear head and an expert on turbos and superchargers. I took him for a ride in the L (he was impressed). He heard the noise and said pretty much what Sal said in the other thread. The rotors are not loaded so they are not fully seated so they may be moving around a bit. As Sal stated, the rubber piece in the stock pulley dampens the vibration. Shouldn't be a problem, but get used to it.