SN 93 Impeller Spacing

[02_872]

Hi guys, I have a SN 93 that we rebuilt over summer. While recently at the tuners it wasn't making any boost but the impeller was spinning. After taking it apart again the backside of the impeller was contacting the housing. There is about .002 in. for space between the two and we are thinking that when the super charger heats up there is enough expansion to allow contact. Is there a spec for how much space is supposed to be behind the back of the impeller and the housing?

Thanks

[64wagon]

take the back housing cover lay it down on a flat table and drop your impeler in. then lay a strat edge across the back of the housing and measure the space from the strat edge to the impeler. now take this measurement and subtract .014" this sum should be your spacing between the main pump and the impeller.

[02_872]

Thanks bromigo, is there somewhere that has this sort of information compiled or is that measurement something you just found that works by messing with these things?

[64wagon]

yes, here read 12 years worth of threads. LOL I talked to Craig with Paradise Wheels last month and and he walked me throuth it.

[02_872]

LOL, I have mine set with .021" on the backside of the impeller and .015" on the intake side, i measured only .006" on the backside the way it was before, no wonder it wasn't working right