GMC SKI

How smooth does the unit run at idle mine tends to make a rattle/high pitched grindee noise but smooths out under boost should i be worried it has 100 miles on it ?
in my 2002 gmc sierra 5.3l short cab sporside
i did i few dyno pulls and got up too 366rwhp
and 364rwtq
what are everyone air fuels running at ?

Black LS1 T/A

Sounds normal to me! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Enjoy your Batmobile. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Todd2001SS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by GMC SKI:
<strong>How smooth does the unit run at idle mine tends to make a rattle/high pitched grindee noise but smooths out under boost should i be worried it has 100 miles on it ?
in my 2002 gmc sierra 5.3l short cab sporside
i did i few dyno pulls and got up too 366rwhp
and 364rwtq
what are everyone air fuels running at ?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Mine has the exact same sound. You could not have described it better.

I have around 100-200 mi on mine also. When you get to 900-1000 rpms it is a sweet whinning noise, at dead idle I hear the same noise as you described.

I even loosened my belt thinking it was to tight, same noise. That grinding noise bothers me a little. The blower really sounds sweet though.

My a/f is at 11.5 till 6g then 12.1.

Todd

GMC SKI

I wonder why they sound grindee like that hhmm worth a phone call to jeremy the tech guy at procharger let you know if he says there something to worry about

MA_sadsaudasjk

They all do it at idle. ATI says that it is gear lash and is normal.It's to bad, as it sounds like a bad power steering pump at idle.

John

Black LS1 T/A

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by MA WS6:
<strong>They all do it at idle. ATI says that it is gear lash and is normal.It's to bad, as it sounds like a bad power steering pump at idle.

John</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ha... that's the way a mechanic described mine when I had the 4.10" Pulley, and I agreed. Most people said it sounded like a jet when i ran it, though. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Funny... the smaller pulley makes it sound more like a whine/whistle sound rather than the sound we've just described here.

Todd2001SS

As long as everyone has the same sound, I think we are fine. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

I can see the thought behind the smaller pulley eliminating that sound. When I just touch the gas it's gone.

I really like the whinning sound of the supercharger, I can't believe folks want that sound to be quiet. It's awesome!

Todd

MelloYellow

So with a smaller 3.40 or 3.20 pulley and a higher idle around 900rpm, the clashing/rattling gears shouldn't be as bad?

You could bump up the idle with the bigger pulleys then. Like people do to smooth out cams, eh?

Black LS1 T/A

Definitely... the smaller pulley got rid of the rattly, bearing noise. It went to a more whistly, slightly screeching noise.

It really DOES remind you of the batmobile screaming by. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Try to check out the video I posted if you can download the .MPG file, you will hear what I mean.

http://www.mlbuie.com/BlackLS1TA/wav...-40_120-23.mpg

<small>[ May 06, 2002, 03:18 PM: Message edited by: Black LS1 T/A ]</small>

Rock

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Black LS1 T/A:
<strong>Definitely... the smaller pulley got rid of the rattly, bearing noise. It went to a more whistly, slightly screeching noise.

It really DOES remind you of the batmobile screaming by. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Try to check out the video I posted if you can download the .MPG file, you will hear what I mean.

http://www.mlbuie.com/BlackLS1TA/wav...-40_120-23.mpg</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Of course.. the blower is spinning faster. The internals don't have a chance to rattle as the load of spinning faster keeps them quiet.

That is why the noise goes away.

Though excessive knocking can be the crank pulley loosening up.