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Dramamine is for DramaQueens
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Discussion Starter #1
IN reading the rules for NASA, are only Supercharged engines required to have inlet restrictors?

3.2.4.3 Supercharger Restrictions for Grand Touring and Super Stock Class
a. Turbocharger and supercharger units must remain as supplied by
the vehicle manufacturer on that model.

b. Intercoolers may in no way be modified, moved or added.

c. All supercharged cars must be fitted with a restrictor fixed to the
compressor housing unless the compressor air inlet internal diameter
is equal to or smaller then the required restrictor internal diameter.

d. If a restrictor is required by (i) above then all air necessary for
feeding the engine must pass through this restrictor but in all cases
must respect the following:

e. The maximum internal diameter of the restrictor is 32 mm and;

f. Be maintained for a minimum distance of 3 mm measured
downstream of a plane perpendicular to the rotational axis situated at
a maximum of 50 mm upstream of a plane passing through the most
upstream extremities of the wheel blades (see Appendix B drawing
254-4).

g. This diameter must be complied with, regardless of the temperature
conditions. The external diameter of the restrictor at its narrowest
point must be less than 38 mm, and must be maintained over a
distance of 5 mm to each side. The mounting of the restrictor onto
the turbocharger must be carried out in such a way that two screws
have to be entirely removed from the body of the compressor, or
from the restrictor, in order to detach the restrictor from the
compressor. Attachment by means of a needle screw is not
authorized. For the installation of this restrictor, it is permitted to remove material from the compressor housing, and to add it, for the sole purpose of attaching the restrictor onto the compressor housing.
The heads of the screws must be pierced so that they can be sealed.
The restrictor must be made from a single material and may be
pierced solely for the purpose of mounting and sealing, which must
be carried out between the mounting screws, between the restrictor
(or the restrictor/compressor housing attachment), the compressor
housing (or the housing/flange attachment) and the turbine housing
(or the housing/flange attachment) (see Appendix B drawing 254-4).
In case of an engine with two parallel compressors, each
compressor must be limited to a maximum intake diameter of 22.6
mm. - Diesel engine: For vehicles with Diesel engines, the restrictor
must have a maximum internal diameter of 35 mm and an external
diameter of 41 mm, in the conditions set out above.
 
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RE: NASA restrictors?

>IN reading the rules for NASA, are only Supercharged engines
>required to have inlet restrictors?

All forced induction engines are required to have compressor
inlet restrictors.

Ivan Orisek
 

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RE: NASA restrictors?

The generally accepted definition for "Supercharging", from the FIA:

"2.3.2) Supercharging:
Increasing the weight of the charge of the fuel-air mixture in the
combustion chamber (over the weight induced by normal
atmospheric pressure, ram effect and dynamic effects in the intake
and/or exhaust systems) by any means whatsoever."

Whether the supercharger is driven by mechnaical means, or exhaust, it's still a supercharger.
 

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Dramamine is for DramaQueens
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Discussion Starter #4
RE: NASA restrictors?

Thanks ...
Using 'forced induction' would be clearer - perhaps
 

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RE: NASA restrictors?

The term 'supercharge' being used to refer to all forced induction systems comes from the FIA rules.

From FIA Article 251, the definition of 'supercharge' is "Increasing the weight of the charge of the fuel-air mixture in the combustion chamber (over the weight induced by normal atmospheric pressure, ram effect and dynamic effects in the intake and/or exhaust systems) by any means whatsoever."

The FIA rules are pretty consistent in their use of the term. Unfortunately, the NASA rules are not so consistent. Sometimes the NASA rules use it in the FIA sense and sometimes their rules use it in the sense of a turbine driven off of the engine (distinct from turbocharge). I think that this can lead to some confusion and NASA may want to clean this up in next year's rulebook.

alan
 
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