Thread: supercharger rattling at low rpm

Hey all. I have a 98 GTP and it makes a rattling sound when it's stopped and in gear. It doesn't make that noise when at higher RPM (1000+). At first we thought it was the steering pump that was causing this problem because the rattling increased when turning the wheel, but today we took off the supercharger belt and the rattling was gone.

We did notice the SC pulley was a little loose when turned on either direction. Does anyone know if this might be a SC problem for sure? We did check the tension pulley spring and it was fine. I'm new to the L67 and have seen that the couplers get worn off and need replacement. Could this be the case?


Thanks,

+1 for the coupler, if you search around there are a few writeup's with pictures showing how to replace it.

jaja thanks guys, I'll ask tomorrow at the local autozone if they have the coupler and the supercharger oil, i bet it's never been changed before.

Originally Posted by Rather B Blown

autozone probably wont have the coupler. Even GM says they cant get them, that you have to get a whole new blower haha. Best bet would be to order one off one of the vendors. I've had no problems with mine, and its a pretty simple install too

Yeah I know what you mean. I went today there and to another autoparts vendor and it was like if I was asking for alien technology when I mentioned a supercharger coupler. I could try GM or another specialized turbo and supercharger vendor here, but they mostly do trucks. I'll just order the oil and the coupler from ZZperformance.

Originally Posted by vsl67

Im going to hope everyone is right and it is the coupler but what you are describing is also the same as stuffed rotor bearings especially if its really loud at idle heres some video of mine with before I replaced the rotor block bearings

YouTube - Eaton M90 rattle

YouTube - Eaton m90 supercharger rattle no 2

Thanks for your input, I think it's a little bit different in my case. It doesn't do it in neutral and when the RPM goes a bit higher, it goes away. I ordered the coupler and the oil from ZZP a few days back, but I don't expect to receive it until a couple more days due to the holidays and the distance. I'll find out once I put in the new coupler.

Also just as a side note, I just did the dog bone flip thing on the engine and the rattling is less now, atleast 50%. It used to annoy me enough at the stoplights that I used to put it in neutral just to make it stop. Now is not loud enough to bother me.

Does anyone know if there's another purpose or effect to flipping the dog bone mounts other than preventing the engine to move so much? I only did it for this reason, but was wondering if there was something else to it.

I'll take a video of my rattling tomorrow and upload it too.

Originally Posted by vsl67

Im going to hope everyone is right and it is the coupler but what you are describing is also the same as stuffed rotor bearings especially if its really loud at idle heres some videos of mine with the rattle before I replaced the rotor block bearings

YouTube - Eaton M90 rattle

YouTube - Eaton m90 supercharger rattle no 2

I know this thread is old, but I am trying to figure out my noise. That actually sounds a little more like the noise I am having. I took the belt off and the noise is a little less, but not gone. Did you just replace all the bearings to fix it? Is this a DIY job or does it require special tools?

So that a holden you are driving? Love the whine of your blower. Do you have it ported or have you done anything to make it sound like that?

The pulley feels tight, so I am guessing it is not the coupler as I originally thought. I do notice that the pulley spins while the engine is running, I guess just the air flowing from the intake turning the guts of the blower. It is fairly strong if I snap the throttle. Is this not enough to cause the bearings to make noise? I can try taking off the other belt and see if the noise goes away. It does seem to be quieter, but did not go away with taking the SC belt off.

Originally Posted by 40th GP

I know this thread is old, but I am trying to figure out my noise. That actually sounds a little more like the noise I am having. I took the belt off and the noise is a little less, but not gone. Did you just replace all the bearings to fix it? Is this a DIY job or does it require special tools?

So that a holden you are driving? Love the whine of your blower. Do you have it ported or have you done anything to make it sound like that?

Thanks Im not entirely sure why mine whine it way its does,But its has a ported TB & supercharger ,4inch tubing and pod and a custom billet rotor block with the recesses in front of the rotors elinimated ,I dont think I have any videos with the last mod yet it made a bit more whine
As for your charger if you disconnect the belt try and stop it from spinning ,I once had a supercharger rattle that kept going even after the belt was disconnect just from the motor spinning the rotors by sucking air through them while driving ,but if its rattling this bad generally you will hear or feel it when you spin the pulley by hand

You can get the coupler here for cheaper, $20 free shipping. I buy them here all the time and they ship quick.

Eaton supercharger coupler M90 Thunderbird Etc S:eBay Motors (item 140369271486 end time Dec-29-09 10:26:27 PST)