François Badoux wrote:

Paul,

I send you in attachment a picture of the new (and final design) air
intake manifold which Gordon designed and which we just finished
testing.  We are going with this design in production.  It will be
cast in magnesium alloy. We found its advantages to be:

- 6% higher VE over the previous design which converted into 6
additional hp
- more compact profile
- cleaner, more elegant design
- Lighter
- considerably simpler and less expnsive to manufacture.

To give you a "historical" comparison of Mistral's manifolds, I send
you another picture showing 3 discarded designs.  From bottom to top:

1. Mistral's first fabricated manifold.  Way too labour intensive to
go into production.

2. Mistral's first cast Mg manifold:  worked fine (the Arrow is still
flying with the same one) but was not optimized for power and was very
difficult and expensive to cast (it was designed before I joined the
project by a young engineer with no industrial experience).  It was
also with that manifold that we found out that the location of the
injector "yards" away from the intakes simply does not work well at
all (bad transients, bad BSFC, exterior AND interior icing of the
intake runners on the N/A engine, etc). I know you are going to say
that locating the injectors on the "hot" side of the engine creates a
fire danger.  That is true and we are addressing the issue by
enclosing the injectors and fuel rail into a closed metal box and
sucking any potential fuel or fuel vapour into the air manifold (see
third picture).  We are also protecting this box with a good heat
shield.

3. The T2 manifold which Gordon designed and built over the holidays
with T1.  It works better than manfold 2 above but is 1-2% less
efficient than T1 over most (but not all) of the RPM range, it is also
bulkier and less esthetically pleasing, don't you think.

Best regards,

Francois

I like your new manifold. Inline everything is good. Be just great cast in
magnesium.

Get rid of the SCAT flex hose and use a smooth bore feed pipe with a ram air
scoop and you will pick up ten HP .... one to two inches of manifold
pressure at high speed.

The butterfly throttle looks of adequate size.

What is the long cylindrical thing on the left with the white wire attached?
Sensor of some sort?

It appears the new hot side is designed for the 2nd gen four port. You will
pick up a lot of port area if you go to the 3rd gen four porting. That may
require a new end housing pattern. If so forget it for
awhile and sell what you have. Here is a shot of a 3rd gen gasket
superimposed on a 2nd gen manifold casting.

Paul Lamar

We measured power without the SCAT flex hose and it makes hardly any
difference at all.  But, obviously, we haven't simulated 1-2" of additional
MAP from ram air effect,that will be the icing on the cake.

The long cylindrical thing is a MAP sensor for our LabView data acquisition
system... Only lab instrumentation...

Francois

 
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