[s-cars] What constitutes a leak?

[chris chambers]

Tony,

That "big hose" splits into a still big hose and a smaller hose that
enters the ISV and then passes to the intake manifold.

But simply, air can't exit the engine if it never enters it. And the
only way it can enter it is through the intake manifold.


I agree you should consider looking for your problem elsewhere.

Regards
Chris



--- Tony Guttmann <T.Guttmann at ms.unimelb.edu.au> wrote:

> Dear Dave,
> 
> s noted in my original message, I also plugged the big hose that
> enters
> the throttle body housing (i.e. the intake manifold an the opposite
> side
> of the block to the exhaust manifold). Thus, as far as I'm aware I'm
> not
> allowing the air to go down each intake runner.
> 
> Does this change your response?
> 
> Thanks,
> 
> Tony
> On Wed, Aug 17, 2005 at 02:18:13PM -0400, djdawson2 at aol.com wrote:
> > Tony,
> > Your expectations for a "leak proof" system are unrealistic.  You
> are expecting to pressurize the intake tract, and have zero leaks...
> is what it sounds like from your description.  When you put a plastic
> bag over the exhaust pipe, you were on the right track, but drawing
> the wrong conclusion.
> >  
> > When you pressurize the intake, where does that air go?  Well,
> first through the turbo compressor housing, then the plumbing (BPV,
> and IC), and finally the intake manifold.  At that point, the
> pressure goes down each intake runner.  If that particular cylinder's
> intake valve is open, the cylinder will fill.  BUT, if it isn't open,
> that cylinder will NOT fill... or fill very slowly.
> >  
> > Suffice it to say that air under pressure WILL (not yelling, just
> declaring the certainty on this fact) go into some cylinders. 
> Likewise, some cylinders WILL have exhaust valves open, or partially
> open.  As a result, you WILL certainly create a path for the air used
> for pressurizing the intake to eventually escape through the exhaust
> system.  This is not a fault, but simply a reality of testing in this
> fashion.  You could be super anal and remove both the intake and
> exhaust camshafts, thereby closing all valves, and reducing (not
> eliminating) all possible paths for air to "leak" past the cylinder
> head.  OR, you could remove your downpipe, and seal the output flange
> on the turbine housing.  Then you would  be able to expect zero, or
> very nearly zero pressure loss.  Bottom line... if the space shuttle
> were powered by a reciprocating engine, the test results would be the
> same... it would "leak"... or more accurately, simply have a path for
> pressure to escape the system.
> _______________________________________________
> S-CAR-List mailing list
> S-CAR-List at audifans.com
> http://www.audifans.com/mailman/listinfo/s-car-list
> 


AUDI - Accelerates Under Demonic Influence.

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com