SN, what is it?

[Sponge]

Hello,

What does mean SN? Are they the old superchargers that need an oil line?

Thank you


Dylan

[JPJP]

SN: SNUB NOSED

Self contained supercharger units...

[speedytang]

The early units('V' Series) had a long front shaft nose to reach the belts and also had a two speed transmission built into them.

[Michael]

SN: SNUB NOSED

Yup! The 'SN' stood for 'Snub Nose' or 'Short Nose'

As per Speedytang's post, when Robert McCulloch began producing superchargers back in the 50s, they had a 2-speed transmission mounted on the front of the supercharger which would vary the impeller speed and engage/disengage the supercharger based on engine load/vacuum. These superchargers were known as the 'Variable Speed' or 'VS' series (ie. VS57).

In later years, this transmission was eliminated in favor of a simpler direct connection. As such, the housing (or nose) which contained all the transmission internals was drastically reduced in size leading to it's description as a short nose supercharger, or 'SN'.

There were a number of SN variants over the years too, from SN67, SN89, SN93, and SN2000. The SN2000 was the last, true SN before Paxton switched their attention to the newly developed NOVI series of superchargers. There were also two other derivatives to the SN that fit within this timeframe: the GSS and the VR4. I don't know much about the GSS supercharger, but the VR4 is THE SN series supercharger to have. It had an improved impeller and larger rear scroll which allowed it to produce twice the CFM and boost pressure compared to all the other SN series superchargers. The good news is that any SN series supercharger can be converted to a VR4 by means of a kit, although finding a VR4 kit nowadays is not easy.

There is a nice website that outlines most of the history of Paxton/McCulloch superchargers called www.vs57.com. Unfortunately, the last time I checked this website was down; hopefully it's just temporary.

As for the SN requiring an oil line, the SN units have a self-contained oil reservoir and a separate oil line is not mandatory. But if you want to extend the length of time between rebuilds or if you plan on using an SN for any type of racing, a oil line and cooler is an absolute must.

Or you can beg speedytang to sell you some of his "secret" red sauce, but nobody here has had much luck in that regard... LOL!!!

Hope that helps.