My blower was quiet

scbird1

Registered User
Well after doing some porting on the blower I cleaned everthing up and got it back to gether and had this strange knocking at idle. I assumed I put the spring in wrong or something but anyway I decided to use a solid plastic coupler. After installing this now the dam thing rattles no knocking now. Its only at idle and the noise is from the bottom of the blower case. It sounds like the bearings are all shot. I only have 87k on the 94 car and the oil in the blower has been changed 3 times. I dont care about the noise but my wife drives this thing half the time and you guys know when they make noise so dose the wife. I just hate takeing the blower off with the EGR its a real pain. Anyone else have this problem?:confused:
 
blower was quiet

Replacing the bearings is your only option to get rid of the noise. Its to bad you didn't replace them when you had it out, now you need a new seal as well. Good luck
 
Well its not the bearings. Just found out from a reliable sorce that the sound im hearing is the rotors chattering together because the motor at a idle pulses and the spring take these pulses out. Now with epoxy coated rotors guess what happends after awhile, yep it wears out and causes the blower to produce less boost. Im going back to the spring coupler if I can figure out which side the orange side goes to. anybody know? and where can I buy a new one. Any part #s? Thanks, Mark
 
Absolutely not. The rotors will ever come in contact with each other. The GEARS provide the isolation not the coupler. The coupler is there to couple the drive pins from the blower shaft to the drive pins on one gear, the gears time the rotors. Unless the bearings in the cartridge, or rear of the case are worn out or the gears have play in them you won’t wear anything on the rotors.

The chattering is from the solid coupler you put in there and is normal. Early blowers with the solid coupling chatter at idle that gets worse as the pins elongate the holes in the coupler.

Jeff
 
But the coupler itself couldnt cause the chatter maybe the gears? When I had the thing apart all was good to my eye and I checked for play in everthing. I guess it wouldnt be so bad if everyone knew the car had a blower but it just sounds like a beater with some worn parts. Now if it was a whine at a stop light that would be cool but the rattles gots to go.
 
No the coupler itself is a great idea and a well made part but on a older blower such as mine and im so dam fussy im just looking for ways to get rid of the rattles. I dont mind if I need to buy a new blower at this point. I just want to know if I can make this one quiet befor I spend the hard cash for a new one.
 
Brand new blower on a 92SC, it rattles at idle. The idle is rough as hell due to the huge cam, but the Supercharger is loud as hell at idle as far as rattles are concerned. Don't assume a new blower will help you at all in that aspect. Rough idle will make even a brand new blower rattle. And it is the coupler, not the rotors rattling. The rotors are timed by the gears, and can not (or certainly should not) touch each other.

Chris
 
me too.....

My blower rattles at idle also, I've had it taken apart a few times by a reputable source, and it still won't go away. I've used the solid and the spring coupler, even had some machining done on the case as well as swapping rotors. Still there at idle.
 
If reinstalling the spring coupler,

3 holes = pulley side
3 slots = blower side

From this post:

post

I had the rattles after a 95 blower snout rebuild and used a solid coupler. I replaced it back with the spring coupler and all is quiet now. Maybe the coated rotors don't like the solid couplers, just a guess.
 
Last edited:
Blower noise

When you guys with noisy blowers hear the noise, how are you listening to it? If you're just standing it front of the engine, that's not good enough. You have to get a stethiscope or something similar and touch it to various parts of the engine while its running. Or, take off the SC belt and run the engine to see if the noise goes away. The water pump and belt tensioners are know to make rattling noises but anything that spins has the potential, so listen carefully to everything you can. I've rebuilt several SC snouts and replacing the bearings & seal is all I've had to do to get rid of the blower rattling noise and I've only encountered the solid coupler. Good luck
 
Are you sure that your tensioners are not shot? Because they will make you think that the blower is making noise.

Kardoctor what keeps your coupler from making noise?

Jeff
 
rattle rattle or

knock knock...same thing did some porting ..and put back together ...knock knock .at idle..that was with a spring loaded coupler..thought I put it in back wards ..apart it comes again ..turn coupler around ....still knocks though different sounding
..decide to try solid coupler.. but it had about a 1/8 inch of play on the pulley picking up the rotors ...and it rattles on idle..and sounds better than knock knock ..conclusion...need new coupler ... since I cut out more of the inlet on the supercharger ..and exposed more of the blade of the rotor there's more pressure placed on all ready stressed out spring ..that's my story and i'm sticking to it ...but the sound does drive me nuts ...
 
Mine rattles too. The nose cone was swapped about 10 months back and a new solid nylon ESM coupler was installed....now that it's got about 5,000 miles on the new coupler the rattle is coming back.

KarDoktor, I would also be interested in hearing about your non-rattle coupler.

David
 
I sent the blower on my 95 to Magnuson Products to be S-modeld about six years ago. When I got it back and installed it, it rattled when the engine idled after it warmed up. I called Magnuson's to see what the problem was and they said send it back and we'll check it out. I sent it back, got a call about a week later from Magnuson's and was told they couldn't find any problems with it at all but that some rattling my be normal depending on application. Got it back, but it back on and it still rattled. Six years later the same blower is in and I haven't had any problems with it but it still rattles. Not so much on start up but after it's warmed up. During this six years it hasn't gotten any better or worse and I havn't noticed any loss of boost. I just learned to live with it. :D
 
Last edited:
My coupler is solid no spring. The holes are interferance fit. When installed there is no paly between the drive and driven dowls.
 
hope this helps

I don't know if this will help, but when i ported the inlet and outlet of my blower case i grinded down some metal off the internal geometry on the bottom of the case- just that sharp point in the middle/front of the case. i grinded it down to form a larger triangular shape blending with the inlet. the reason i did that was to increase the sweep area allowing the rotors sweep up more air attempting to make it more efficient. i think this had a positive effect on my blower in two ways. first it reduced the rotor chatter somewhat (the scraping/knock sound), and it may have reduced the internal temperature the thing develops.

It did make my blower much quieter at idle (hardly makes any noise), before i did this my blower was talking to me like everyone elses, and i'm still using the spring coupler. whines much louder when i put my foot in it though. no boost losses that i can see- i'm hitting 16 psi peak.
 
Last edited:
Back
Top