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

Francois, I am very glad you are making these, and I am sure you will sell
many to those doing their own engines.  I take it that you are going to
re-locate the turbo as this latest manifold will not fit with the stock
turbo or most of the aftermarket manifolds.

Looks great though.

Dave Leonard

 
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