Housing on the back of blowers

[Ghoste]

Looking at a Pro Mod car last week I was left with two questions.  First, what is in the housing on the back of the case?  It extends well past the portion of the blower that is located over the manifold and doesn't appear like it has anything to do with the pressurizing of air.
Secondly, on part of the throttle linkage to the thing, there was an electric solenoid that didn't appear to act on anything.  What was the purpose of that?

[John_Kunkel]

Most of those rigs run a 14-71 blower on a manifold that's designed for the 6-71, since the 14-71 is much longer than the 6-71 the rear of the blower case extends out over the back of the manifold.

Most solenoids are for use with nitrous oxide but that's not allowed on NHRA supercharged Pro Mod cars, the deactived solenoid might be there for nitrous use on non-NHRA sancioned events. 

[Ghoste]

I should have taken a picture to better ask this question. The solenoid was attached to the linkage itself and was just hanging there like a dashpot on a carb but with nothing for it to act against.  Thanks John.