[s-cars] "Negative Boost", Oh yes Martha its that dreaded

[djdawson2 at aol.com]

 Yeah... the one I used on my S4 was about 12 inches long, had a diameter of 8 inches, and had a 4 inch inlet.  It was quite large.

It didn't show any signs of collapse.

 


 

 

-----Original Message-----
From: Jared Robinson <chapel976 at gmail.com>
To: Ben Swann <benswann at verizon.net>
Cc: s-car-list at audifans.com
Sent: Wed, Oct 6, 2010 2:58 pm
Subject: Re: [s-cars] "Negative Boost", Oh yes Martha its that dreaded


The filter I had to run on my 9-5 Aero was over 10" long and 5" in diameter
at the base...

On Tue, Oct 5, 2010 at 3:04 PM, Ben Swann <benswann at verizon.net> wrote:

> Do the math - just sticking to basic algebra to get the idea, since a
> calculus version
> would be more involved..
>
> Let's say you are running a measly 25 PSI of positive pressure - so that is
> only 25
> pounds per square inch of surface area - multiplied by how much surface
> area?
>
> Lets see - that FilterHosen looks like it is at least 3" in inside diameter
>  and about
> 5" long  in the deformable area - so pi * Sq.diam is the cross section
> gives about 706
> pounds of force on just the cross-section area of the tube - multiply by
> your length and
> we have a force equivalent of a hand crushing around the pipe of some 2800
> lb.
> Uniformly distributed, so not as bad as it sounds, but enough to do that
> sort of damage
> - if it were a normal rubber boost hose it would have blown out.  In this
> case, the
> force was more of a Bernoulli suction inward, and the outside air pressure
> as an
> equalizer, but you get the idea.
>
> This is why the filter intake needs to be so much larger than the rest of
> the induction
> piping.
>
> Ben
>
> [Date: Mon, 4 Oct 2010 19:30:47 -0600
> From: Hap Maguire <captmagu at gmail.com>
> Subject: [s-cars] "Negative Boost",     Oh yes Martha its that dreaded
>        subject once again
> To: s-car-list <s-car-list at audifans.com>
> Message-ID: <5ABAD6D1-16DC-48B5-95AB-D2913B3C17B0 at gmail.com>
> Content-Type: text/plain; charset=us-ascii
>
> S-Heads
>
> A sporadic boost issue has been driving Tufty Jones, Brendan Rudak and
> yours truly very
> crazy for the last several months. Last week Brendan and I set about
> logging runs on da
> computer to see if there was a software issue and everything checked out
> perfectly. We
> even tried swapping out the Tial 44mm wastegate for a plug and play
> Turbosmart WG with a
> minor change invloving a slightly laggier but still inconsistent boost
> between 10-15 lbs
> due to a 7 lb vs 1 bar spring in the Turbosmart WG. Tufty and I finally
> decided to do an
> intake tract leak check even though we knew it couldn't be that as this car
> has
> basically a full hard pipe tract with the only silicon pieces at the joints
> for engine
> flex. This would also eliminate the BOV as a potential source. Well as the
> pressure
> built upwards of 30 lbs the only leak we found was from the test valve. The
> intake was
> solid. To do the test though, we had to remove the 4" elbow that runs from
> the air
> cleaner to the turbo inlet. As Tufty was  scratching his head yet again he
> took a good
> look at the cleaner and Voila, we had found our "Negative Boostie".
>
> As you can see from this inside view, the plastic frame has broken down.
> This allowed
> the cleaner to shrink in on itself as Da BEEG Comp turbo literally sucked
> the life from
> its veins. You can also see the crease lines on the outside of the cleaner
> and visualize
> what was going on.
>
> http://i935.photobucket.com/albums/ad199/hapster47/a-1-3.jpg
>
> http://i935.photobucket.com/albums/ad199/hapster47/a-3-1.jpg
>
> This air cleaner was mounted to a 4" aluminum pipe that had a 90 degree
> bend and the
> cleaner just hung from the pipe without touching anything else. You can
> just see the
> pipe here in this shot.
>
> http://i935.photobucket.com/albums/ad199/hapster47/dm-63.jpg
>
> Well mucho thanks to Tufty and Brendan for their continuing help in
> perfecting this
> beast. Something tells me this is gonna be a long story. Throughout this
> all, the car
> still ran beautifully if somewhat muffled because of the cleaner. I gotta
> see if I can
> get a refund or do you think AEM will just laugh???
>
> Hap, wit dakine "Negative Boost" nomoh not(and yes Mr Baloney that's 3
> negatives) from
> Evahboost, Maguire]
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>



-- 
Jared Robinson
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