Sportfish

I tried the search feature and read lots of responses, but couldn't find one for my question. Two days ago I finished the installation of a Magnacharger Radix on my 2003 Silverado 5.3L. That day I did a few test drives and gradually worked up to a few brief full throttle operations as the instruction manual recommends. All was well, however I was quite surprised at the howl under even partial throttle. It drowned out my Flowmaster exhaust. Under no load and idle it was as quiet as it was when stock. The second day, I drove it to work and it sounded the same. However, on the drive home, I began to hear noise at constant throttle and idle. When I got home, I left it running and when I got out, I could hear the noise quite well. I popped the hood and the noise was definitely coming from the supercharger. It sounds like a bad water pump bearing. I'm surprised at this because all of Magnacharger's information indicates their system is quiet due to technical advances in rotor constuction, improved machining, and better bearings.

I don't mind the open throttle howl, if that's normal, but the low speed and idle noise concerns me. I sure don't want anything coming apart and getting sucked into my engine. For those of you with Magnachargers, are these normal sounds?

Sportfish

The response I received from the vendor:

"It is hard to gauge the sound without not being physically there. If it is a whine noise or a "whoooo" noise then that might be a normal sound. The supercharger creates a vortex which normally makes a whine noise which is very common on all superchargers.

Now if the noise is more of a grinding noise OR if you are hearing a loud high pitch sound then there might be something else wrong. Normally when it is an issue like this the noise gets worst over time. So weekly you will hear the noise increase."

Not much help and why I hope someone here can give me a better evaluation based on personal experience. I'm certainly not going to drive it until it "gets worst over time".

Jontall

First check the oil in it. If it has oil, remove the serpentine belt and turn it by hand. It should be very easy to turn and silent with no slack/drag/grinding. Call Magna Charger's tech support line-- they're excellent.
Magna Charger, Inc.
1990 Knoll Drive
Ventura, CA 93003
(805) 642-8833 - Phone
(805) 677-4897 - Fax
Hours: M-F 8:30AM-5:00PM (PST)

old motorhead

iTrader: (10)

I have an MP122 and TVS2300. Both are fairly quiet out of boost. The TVS being a little quieter. I did have an idler bearing go out on my MP122 setup that did make a lot of noise. Easy to find by taking the belt off and spinning each idler. Easily fixed by knocking the bad bearing out and replacing with a commonly available bearing from my local NAPA. Both my current MP122 and the MP112 before it had a little slack internally in the blowers. As long as the motors were running smoothly, there was little noise. I had a fairly aggressive cam in my 5.3L with MP112 and you could hear a little rotor knock whenever the engine was running rough. Mainly during cold starts.

Something doesn't sound quite rite. I've never had as much noise as you are describing out of any of my three Magnuson blowers. Did you buy a used MP112? What size pulley do you have on the snout? Front drive? If you can get ahold of a mechanic's stethascope, you might be able to determine from where the noise is originating.

Sportfish

Thanks. This is a brand new kit, shipped straight from Magnesun. Shouldn't have any lubrication or bearing issues. After I told the vendor that I wasn't satisfied with his response, he offered a bit more information:

"If the "gear or bearing noise" is at very low idle up to around 1,000 RPM, then that might be the common gear noise that all superchargers make. To me I consider it a grinding noise, similar to the noise that grinding coffee beans sounds like. This grinding noise normally will eliminate as you increase the throttle and that is when the supercharger whine noise will come into play. In all honestly to me it almost sounds like you are explaining the common gear noise it makes at idle.

On a side note too, the supercharger rotors are covered in a Teflon coating, which normally requires a break in time. The Teflon coating acts like a sealing agent which over times fills in the gaps and provides a smooth finish to help absorb sound. So it is also very common that during the break in time the Teflon coating will fill in the gaps to help soften some sounds."

That makes me a little more comfortable. I guess I'll drive it a few more days and see if the noise changes.

old motorhead

iTrader: (10)

Yes, it sounds like you need to go out and "enjoy" it a little. I bet the maggie makes that stepside feel 1500 lbs lighter.

Sportfish

Yesterday on the drive home from work, the noise got progressively louder. When I got home, I opened the hood and used the long screwdriver stethoscope method and isolated the noise to the new tensioner assembly plate. I removed the serpentine belt and turned each pulley by hand. The original idler pulley that was removed and transferred to the new tensioner assembly would hardly turn. I took it off and found a groove worn into the new tensioner assembly plate behind the idler pulley. I noticed that the idler pulley bearing was about 1/8" in from the outer edge of the pulley. It should be flush with the edge. This offset caused the pulley to be positioned too close to the mounting plate and the thermal expansion from the higher afternoon ambient temperature and engine temperature was causing the pulley lip to contact the tensioner assembly plate and cause the noise. After I pressed the pulley into its proper position and reinstalled it, the noise was gone. All is well, and yes, time to enjoy it...more than a little!

old motorhead

iTrader: (10)

Glad it was something simple....and cheap