Intake manifold construction, intercoolers

[James Montebello]

This is true, but with one big caveat, already mentioned several times:
throttle response with one "big-arsed" plenum and one throttle will be
pretty awful.  The entire volume must change before each intake valve
"sees" the change being demanded by the driver.  An IR setup with a
throttle per cylinder, however, will have excellent throttle response,
simply because the volume between the throttle and the valve(s) will be
small.  However, a multi-throttle setup is more complicated to put
together and keep operating than one with only one or two throttles. So,
the compromise is two plenums, each relatively small, and two throttle
bodies.  Reasonably good throttle response, and reasonably good flow.  
Not as good as an IR setup, but a lot less complicated.

james montebello

On Wed, 5 Dec 2001, Bruce wrote:

> 
> I was trying to find it, but there is a net site where they get into
> Hemholtz and manifolding.  On the V6s they contend that two groups of 3 are
> the best answer.
>    Needless to say, I'm of the single plenum thought pattern.
> The closer the runners face an volume of air approaching atmospheric, the
> better they will flow.   Of all the manifolding available which generates
> both the best torque and HP numbers?.   The lowly Independent Runner.
> There are several jillion theories as to why, but IMO, it's just a matter of
> the air not having to snake around at all to get to the intake valve.  I got
> to work with alot of IR manifolds, and engines, and have yet to see anything
> approach them.  Now, they use individual butterflies, but the answer to why
> is that they have too.  Now how would one try to approximate an IR with
> Simplicity in mind? (No Correction Needed).   Use your runners and tie them
> to a big arsed plenum, and single butterfly.  the large plenum will
> approximate the atmosphere, or in this case, be the atmosphere, and with the
> single butterfly the entering air will have the least inertia, and so will
> be able to bend around to  best fill the plenum.
> Bruce
> 
>      Note:  The sender is not responsible for your interest or lack thereof
> in the contents of this posting.  This Warning is included as part of to
> ensure that people who ARE NOT LIKE ME are in no way offended or
> disadvantaged.
> 
> 
> 
> > Additionally, why two plenums and two TBs?  I can see it if you're doing
> > twin turbo but otherwise I don't see it.  I'd just go for the most direct
> > means of delivering the air to the cylinder, trying to line up the port in
> > the head with the runner as well as possible.
> > Craig Dotson
> 
> ----------------------------------------------------------------------------
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
> 
> 

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org