[s-cars] where's my intake whine?

[Jerry Scott]

Mike
Depending on the mileage of your car, this could be the bearings in the 
turbo going bad and starting to get noisy.  You can test this by 
removing the intake hose and moving the turbine with your finger.  Check 
to see if it has any axial or radial slop.  There should be practically 
none.  The turbo can go a long time with this condition before it stops 
turning.  They are rebuildable as I recall for around $335.

Others I'm sure will pipe in on this noise which could be totally 
something else other than the turbo.
Jerry

Mike Fitton wrote:

>Okay, I'll go ahead and admit that I've been lazy and haven't even 
>attempted to pressurize the intake and see what's up.
>
>With that out of the way, here are the symptoms.  When the engine's cold 
>there's a very noticeable whine whenever the boost gauge reads to the 
>right of about 5inHg.  I don't usually boost it at all when it's cold, 
>but in the interest of science I decided to a few times.  It makes the 
>whine under light vacuum, light boost, and dead in the middle as far as 
>I can tell.  The noise mostly goes away when the engine's fully warm.
>
>I don't seem to be having any trouble achieving my usual max boost in 
>the low 20s.  It's possible that I'm imagining it, but it might be 
>taking slightly longer to get there.  If it is, I wonder if that could 
>just be climate change (seasonal kind, not Soylent Green kind).
>
>I could very well be mistaken, as this one has only happened once.  I 
>think I once heard the diverter valve activate momentarily while I was 
>full throttle on an on-ramp.  I glanced at the gauge and didn't see it 
>moving, so either I imagined it or didn't look in time.  I haven't 
>noticed any other strange noises that sound like a failing DV.  It's a 
>metal Forge valve, so maybe it makes different sounds than the 
>well-documented failing stock DVs.
>
>I've been itching to buy the Apikol IC kit, but I don't want to spend 
>the money now if I don't have to...especially if the problem is with a 
>part that kit doesn't include.  I've gone through and tightened/replaced 
>as many of the intake clamps as I can easily reach, but to no apparent 
>avail.  Visually, everything appears to be in order.
>
>Any thoughts?  Make a pressure tester?
>
>-Cheers!
>Mike
>
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