How-To: Magnuson Blower Rebuild

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photos by Jeremy Stanton, Stephen Brooks and the author

A Magnuson Radix Revamp — Straight from the Source!

After 110,000 trouble-free miles, the Magnuson supercharger on our regular cab, stepside (RCSS) 2003 Silverado show- and tow-truck started making a faint noise we’d never heard before. Although it was faint, we mean, really faint, we thought it best to pull the polished M112 Radix blower off and visit Magnuson Superchargers in sunny Ventura, California for a full rebuild on our trusty supercharger.

That’s right; Magnuson doesn’t just sell new world-class supercharger systems, they also have a complete in-house service facility that rebuilds and refinishes just about any Eaton supercharger, including those from OEM applications like TRD, Ford and Chevrolet. If that’s not cool enough, service time on a supercharger rebuild is typically less than a week and every rebuilt blower is tested on a high-tech supercharger dyno to ensure it’s ready for big boost and many more miles.

The MP112 blower and our RCSS Chevrolet Silverado

Long before the current TVS line of blowers, the Eaton M- and MP-series of superchargers were the hot ticket. After a long run of successful blowers found in OEM applications like the Terminator Cobra (M112) and Ford Lightning and Cadillac STS-V and XLR-V (M122), Eaton took the legendary pair of three-lobe rotors and made them high-helix units (adding the “P” to the “M” and creating the MP112 and MP122) with 60-degrees of overall twist for greater efficiency and cooler discharge temperatures.

The fifth-generation Eaton supercharger rotors displace 112-cubic inches per revolution for great flow potential and efficiency, but Magnuson took it one step further when it slid them into a high-flow proprietary case and then augmented it with S Port technology that utilizes an integral bypass valve to keep fuel efficiency high during partial-throttle cruising where the blower can “free-spin,” and power potential up thanks to a claimed 90% volumetrically efficiency. When added to Magnuson’s legendary supercharger kit components, like the air-to-water intercooler systems that keep inlet temps at bay, that are known for their extreme completeness, power production and emissions compliancy, it’s easy to see why we had well over 100,000 trouble free miles.

At approximately 30,000 miles, our Dark Carmine Red Metallic RCSS Silverado received a polished Magnuson Radix supercharger kit along with Belltech suspension and ultra rare polished Halibrand 6-bean rims. In one hit, the truck went from a stock cruiser to a low 13-second show, go, and tow-truck that served as a daily driver and a tow-rig pulling around project cars for the past decade.

After 10 trouble-free years, as we mentioned earlier, the blower started making a faint noise we’d never heard before, so a quick call to Magnusson revealed they had a full service facility and we could ship them the blower, bring them the blower, or bring them the truck—we popped the blower off, threw it in the trunk of a rental and bombed down to the Magnusson headquarters for a blower overhaul and a full facilities tour.

The Rebuild Process

As mentioned, Magnuson’s in-house service center can rebuild or refurbish a supercharger from components to complete in just a few days, which means your supercharged race car, weekend warrior or daily driver will be back on the road in no-time.

Although we previously had no idea that Magnuson had such a service, we were obviously in the minority since there was an entire shelf of different blowers waiting for a refurbish, a rebuild, or just some parts.

Follow along with the captions as we take you inside the world-class facilities for a Maggie revamp straight from the factory itself. To put it into perspective; it’s like taking your Camaro back to GM for a factory resto and refresh. How’s that for legit?

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Mike, a senior tech at Magnuson, manages the service facility at the headquarters made quick work of our Radix 112 supercharger rebuild by immediately taking it down to the bare parts.


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Mike started the teardown by splitting the upper and lower intake manifold apart. He carefully inspected every nut, bolt and inch of the parts in search of any problem areas.


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After the intercooler is removed and the blower is separated from the plenum, the snout of the supercharger comes off next. Behind the cover you’ll find the torsional isolator, which we thought might be the culprit of our additional noise, and while it appeared to be worn, it was still within spec.


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Mike then removed the rotor pack to inspect for any blemishes or damage. In our case, even after 110,000 miles, the blades still looked good–a true testament to the quality of the Magnuson blower.


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The blower gears are then inspected statically and while being rotated to make sure nothing is out of the norm.


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The front pulley, bearing and the internal components of the blower snout are next on the list to leave the building.


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The front supercharger bearings are inspected to make sure nothing is notched or out of spec.



Mike even checked the blower snout case for roundness to insure nothing was going to be a problem after the rebuild.


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Now the bypass valve and its associated components can be inspected and then removed.


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There are two bearings pressed into the supercharger case. Mike heats them to aide in the removal process.



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Way down inside the case are the two aforementioned bearings that must be removed before the case can be thoroughly inspected and cleaned.



After a quick hone, the blower case is inspected and then it’s ready to be properly cleaned.


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Off to the cleaners they go; Magnuson literally rebuilds and refurbishes the superchargers back to like-new condition.



After the supercharger is disassembled down to the bare components, Mike heads into the warehouse to get all of the necessary parts for the rebuild. Magnuson keeps thousands of parts on hand so turn-around time on a blower rebuild is just a few days.


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Now it’s time for everything to come back together after a thorough inspection and new fittings and bearings. The main snout shaft is greased and mated to new bearings before it will be pressed into place.



The original pulley is put back in place and torqued to the factory specs.


Remember the two small bearings mounted inside the case? Here they can be seen mounted to Magnuson’s tooling that will press them in place.

Remember the two small bearings mounted inside the case? Here they can be seen mounted to Magnuson’s tooling that will press them in place.



Here the press and the proprietary tooling come together to press the bearings into the case.


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All new bypass valve support hardware is installed to make sure the blower is as good as new.


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Magnuson is beyond choosy, and uses all different types of sealers and thread lockers to ensure supercharged success.



After the supercharger innards have been put back inside the case, the blower snout is then mounted to the case.



The manifold is placed in an ultrasonic cleaner and comes out as good as new.


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Mike even replaces all of the original O-rings with new versions for a leak-free fit.


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Magnuson also uses all sorts of high-tech sealant to ensure no boost will be lost.


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They’re also adamant about torqueing everything in sequence and to the appropriate specs.


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Finally, it’s time for the supercharger and the upper part of the manifold to sandwich the intercooler and the inner components between the lower manifold.


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Have we mentioned that Magnuson is thorough? They even replace all of the fuel injector O-rings.


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Next up is some supercharger oil and then it’s time to hear this blower whine.


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Magnuson tests all rebuilt or refurbished superchargers on their high-tech supercharger dyno. It was a treat to hear the blower run up and down through it’s operating RPM range and through a myriad of tests to ensure it was ready for big boost.


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After a complete overhaul, the superchargers are then packed up and shipped back to happy customers.

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