AW: Intake manifold construction, intercoolers

[Rausch, Bernd]

Hello Bruce,

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.

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.

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)!

Best regards,
Bernd

-----Ursprüngliche Nachricht-----
Von: Bruce [mailto:nacelp at bright.net]
Gesendet: Dienstag, 4. Dezember 2001 14:15
An: diy_efi at diy-efi.org
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




----- Original Message -----
From: "Rausch, Bernd" <br at rnt.de>
To: "Rausch, Bernd" <br at rnt.de>; <diy_efi at diy-efi.org>
Sent: Tuesday, December 04, 2001 3:04 AM
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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