With the volute removed, Greg...
With the volute removed, Greg checks the index mark on our Novi's impeller to see if it has spun abnormally or the shaft has twisted.
If you haven't figured it out yet, we're talking about supercharger maintenance. Keeping tabs on a blower's mechanical condition is something we suspect many of you don't give much thought until the 'charger no longer functions as it should (decreased boost, leaking, abnormal noise) or experiences a catastrophic failure of some sort, which could possibly lead to engine damage as well. So, with our blower already at Paxton for the volute transformation, there's no better time than the present to also have the unit gone over (thoroughly inspected, cleaned, and rejuvenated with new seals, bearings, and shims, as well as gears or other hard parts if necessary) by the company's factory-trained supercharger specialists. When you consider the extreme heat and high-rpm duress that superchargers endure when you're really getting after it in your Pony-on the street and especially at the track-we think it's critical that you pay attention to the blower and follow our lead by having it serviced before the worst happens.
We often talk about projects and upgrades that are easy enough for do-it-yourself-minded enthusiasts. Contrary to what you may think, servicing a blower is not among those easy tasks: It should be left to the experts at Paxton/Vortech.
Greg Dawley is the supercharger guru helping us. Greg is one of two technicians at Paxton who are responsible for all of the supercharger inspections and by-hand rebuilds performed once a blower is received.
Once trueness is verified,...
Once trueness is verified, the impeller is removed from its base.
Our Novi wasn't critical, but thanks to the 65,000-rpm impeller speed it sees on the dyno, Greg noticed that the lower bearing on its impeller shaft was a bit rougher than it should be, and we also had some minor leakage at the impeller seal. We use a 3-inch race pulley to achieve 20 psi of boost and this type of impeller speed at 6,800-7,000 engine rpm. An 8-psi, street Novi 2000's normal rev limit is about 55,000 rpm.
The following photos and captions take you inside the blower, if you will, and detail the factory maintenance process for our Novi 2000. We shadowed Greg's every move, and learned quite a few interesting things about the type of damage a supercharger can incur-and more importantly, things to look or listen for to determine whether your blower is damaged.
This steel seal pulls double duty in the supercharger's operation by retaining the impeller's rubber seal (and completing the overall mechanical seal between the transmission and impeller's mating ring) and also creating clearance between the back of the impeller and the volute. A blower won't function properly if this spacer is not in place or is the wrong size.
Greg lifts the Novi's transmission cover off its base for access to the gears inside. Note that the cover must be removed evenly, and special tools are required for its extraction to prevent damage to either mating surface or their locating dowels. This is why we think it's best that you send your blower to Paxton for service or repair before trying such work on your own.
The transmission represents ground zero in a centrifugal supercharger. Greg removes our blower's pulley and impeller gearsets by pulling them straight up and out of the case simultaneously to avoid damaging teeth on either gear. Paxton shaft and gear combinations are machined as one piece as opposed to gears pressed onto the shafts separately, as they are done with Vortech superchargers.