Intake manifold construction, intercoolers

[Bruce]

From: "Rausch, Bernd" <br at rnt.de>
Subject: AW: Intake manifold construction, intercoolers
> thanks for your response. Your input (and that of others, of course)is
> really welcome. But I disagree in several points:
> I want to use one Spearco air/liquid intercooler per side (V-engine),
> this IC is 4.5"x4.5"x10" and rated for 700cfm each. The engine will need
> about 800-850cfm for 650hp.
> With the IC in the plenum, I will actually cool the plenum and gain IC
> area this way (normally with a hot plenum and runners you heat your
> intake charge). I thought about building carbon intake runners, to
> insulate the runners and the plenum from the heat of the cylinder head.

You going to use a total of 4.5x9x10 for cooling an engine of 650 HP?.
Is this a dragster, or just for really short bursts of speed?.
what are your plans for cooling the liquid?.
CF for a large ehough plenum to hold all this is going to need some serious
ribbing to prevent a sneeze from rupturing it.

> I want to make big plenums, about 1,5L *after* the core (displacement of
> the engine is 3L total). So the core will not straighten the flow to
> much.

Your going to have the air going thru a 4.5 core and then want it to bend
immediately?.  Ugh, OK, I don't see it happening that way, but it's your
decision.

> Think of it this way: If I use the same IC (of which I assume that it is
> the right size for the application) with a "classic" setup
> (IC->TB->plenum), all I am doing is to avoid the transition form the
> intercooler core to a 2,5" pipe and the transition from the pipe to the
> manifold (and a 90deg bend, since my TB is mounted on the side of the
> plenum)!

Me thinks your toooo concerned about an elbow.  Is it some really small
radius?.
Again, I think your thinking in N/A terms, not T/C
Bruce

> Best regards,
> Bernd
>
> -----Ursprüngliche Nachricht-----
> Von: Bruce [mailto:nacelp at bright.net]
> Betreff: Re: Intake manifold construction, intercoolers
> Any intercooler that you use in the plenum, would either be too small to
> be effective, or need fluids that are really cold.  you'll also be losing
> the surface area of the piping for heat transfer.  With the in plenum
> cooler, you also be exposing it to the heat of the manifold, thru all it
mounts,
> and you libel to losing alot  of cooling effect to cooling the manifold.
> For a plenum to be effective the opening intake valve must be able to draw
> against the plenum, having the finning in the plenum is going to
**straighten**
> the air flow, and so the opening valve is going to have to *try* and have
> this air change direction, rather then drawing against a rather turbulent
> chamber of waves, and air movement.  BTW, this is the same set up as
> International Harvester uses on some of it's deisel applications, but they
are
> extremely low rpm motors.  They also have an area above the I/C that is
about
> equal to the area below it.  I think you'd have to have a really huge
plenum for
> any kind of free reving motor to really work,  in the IH version they use
> coolant in the I/C so as to just reduce the high peaks of air temp..
>   I think it's a stop gap measure, and limited in practical application.
> For a diesel tractor working in the fields it's OK.
>   I had choices of 2.5 and 3.0" piping for the front mount I/C in my GN,
> and after some investigation think my original thoughts of using the 3"
> are best.  Trading a little off idle / low rpm response for cooler
ultimate
> flow should be worth while.  I'm lucky in so far as mine is an automatic
> trannied car, so I can tolerate the lack of really down low torque since
> converter slippage with be absorbing that loss anyway, or rather allowing
the
> engine to rev thru that zone in a lightly loaded state.
>   Huge preturbo plumbing, large post turbo, as much I/C as can be
> fitted, and calibrate as necessary.   then finalize the hardware to best
use the
> above.  At least that's the way I'm headed.
> Bruce

> From: "Rausch, Bernd" br at rnt.de
> Subject: Intake manifold construction, intercoolers

> > Thanks for the responses I got, I have some additional questions:
> > At the moment, I have an air/air intercooler per side (twinturbo V
> > engine). I have per side: three 90deg bends, about 2m piping, two
> > intercooler mandifolds with 90deg bends and four silicone hoses.
> > I am thinking of welding an air/liquid intercooler core from Spearco
> > directly in the intake plenum. The throttle body will be upstream of
> the intercooler. With this construction I can exit the turbo in a straigt
> > line, with an expanding pipe of about 0.4m to the throttle body. I
> will only need one hose (turbo has a flange at the outlet). This setup
will
> > save me five 90deg bends, 1.6m piping, three silicone hoses and two
> > manifolds at the intercooler per side.
> >
> >       TB   IC     intake runners
> >        |---------|------------|
> >        |   ||    |------------|
> > -------|   ||    |
> >  ->    /   ||    |------------|
> > -------|   ||    |------------|
> >        |   ||    |
> >        |   ||    |------------|
> >        |---------|------------|
> >
> > -Is there any downside of this setup ?
> > -How do I calculate intake plenum volume ? Only the volume on the
> > downstream side of the intercooler or the complete plenum including
> > intercooler ?
> > Any help would be appreciated.
> > Bernd
> >
> ------------------------------------------------------------------------


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