Trilogy rattle?

[Blackened300a]

On the way back from the track I noticed a slight rattle coming from under the hood around 2500 rpms just before the blower would start to whine. I pulled over and working the throttle by hand I was able replicate the sound which seems to be inside of the blower. It also wasn't constant and seemed to be gone by the time I got home and didn't affect the performance.

Is this a normal harmonic of the blower or is a bearing on the way out? At idle it's quiet and below 2500rpms it is also quiet. Plus the whine and power delivery are the same as it was.

[boatmangc]

Is it ported?

[RacerX]

Coupler. There's a phenolic/plastic coupler in between the drive rotor and the snout drive shaft. There's slight vibration (which is why we have harmonic balancers) that slowly wears the circles into ovals. Pretty easy to replace. ZZ performance has them.

http://rollingperformance.com/sccouplertemp.jpg

http://i240.photobucket.com/albums/ff27/karmag3/coupler%20change/IMGP0511.jpg

http://photos1.blogger.com/blogger/3808/1845/320/CouplerAssembly.jpg

[Blackened300a]

Is it ported?

Yeah. Posi ported.

I was thinking about pulling the belt off and checking for play. I was guessing coupler and then upgrading.

[babbage]

Coupler. There's a phenolic/plastic coupler in between the drive rotor and the snout drive shaft. There's slight vibration (which is why we have harmonic balancers) that slowly wears the circles into ovals. Pretty easy to replace. ZZ performance has them.

http://rollingperformance.com/sccouplertemp.jpg

http://i240.photobucket.com/albums/ff27/karmag3/coupler%20change/IMGP0511.jpg

http://photos1.blogger.com/blogger/3808/1845/320/CouplerAssembly.jpg

^^
Always great info from this guy!

Looks like a pretty easy job, do you loose the blower oil changing that?

Time to tear it apart - nbd right paul?! :D Nice timeslip too.

[RacerX]

ZZperformance sells the kits pretty cheap which includes the sc oil. May as well change it out while you're in there. A big ole syringe comes in the kit to make it less messy to slurp the old oil out before you pull it apart.
http://www.ebay.com/itm/Eaton-GM-Ford-OEM-Supercharger-Coupler-Repair-Kit-Combo-w-2-GM-oil-/110882711243?pt=Motors_Car_Tru ck_Parts_Accessories&hash=item19d11fe6cb&vxp=mtr

[Blown3.8]

Paul's blower still has the spring coupler. Definatly pull the belt and check for excess play. And its and easy job once the blower is off the car. Unfortunatly the trilogy's sit down in the blower plate and you can't get the snout off on the car.

[Blackened300a]

Here's a example of what I'm hearing. If I remove the line from the bypass and it puts air into the engine, since the engine isn't using that air it will bounce it back. That's how I can replicate the sound I'm hearing around 2k-2500 rpm.
The bypass has plenty of pressure in it and its working fine when I work the throttle by hand.
Could it be hooked up wrong and it's not seeing boost and vacuum? I wanted to pull the cowl off the situate the lines behind the blower to see what it looks like.
t9n6BK59c7I

[Blown3.8]

That blower sounds normal when you pull the vac line. It may be closing the bypass early when you are driving.What does the boost gauge do when driving? Does it go smoothly thru vacuum to boost or is there an abrupt switch from vac to boost?

Check the bypass with the car off. Pull the vac hose push the arm all the way n then put your finger over the nipple and see if the arm stays in for at least 10 seconds. The arm will come back out a little after you let it go, just make sure it doesn't move all the way out. If it won't hold the vacuum then the bypass is not sealing so that could make it close early and give you that sound. If it holds open then check your vacuum lines.

[Blackened300a]

That blower sounds normal when you pull the vac line. It may be closing the bypass early when you are driving.What does the boost gauge do when driving? Does it go smoothly thru vacuum to boost or is there an abrupt switch from vac to boost?

Check the bypass with the car off. Pull the vac hose push the arm all the way n then put your finger over the nipple and see if the arm stays in for at least 10 seconds. The arm will come back out a little after you let it go, just make sure it doesn't move all the way out. If it won't hold the vacuum then the bypass is not sealing so that could make it close early and give you that sound. If it holds open then check your vacuum lines.

I don't have a boost gauge hooked up to check if it's dropping back. I will check the bypass this morning and see if it's holding pressure. I only noticed this after my second run at the track pulling back around to the parking area so it's possible something came loose behind the blower.

Thanks Chris.

[Blackened300a]

Bypass is good, holding pressure as long as I held the port closed. I wanna pull the cowl and go through the vacuum routing. Perhaps something came loose or rubbed through.
I plan on attacking this tomorrow.

[Joe Walsh]

I'm sorry Paul, but I couldn't see what you were doing on your engine in that video because of all that reflection and glare!

P.S.
Hope that you find the rattle, as I know how odd engine sounds drive me crazy.

[Blackened300a]

Took the wiper cowl off today and didnt see anything that stood out. I rerouted a few things, made adjustments and found the hose to the brake booster out the back of the blower was a little loose. Installed a clamp, and took it for a ride with the cowl still off. The noise was pronounced as it was before but everything feels and drives normal. Get home, reinstalled the cowl and go for another ride. Now it sounds normal with no rattles or abnormal sounds. I still hear the blower mechanical noise , but its nothing like it was before. I wonder if I moved something that was echoing through the cabin or its quiet now and will make noise the next time I take it out?

Being overly tuned into the sounds of this car gets real irritating!

[justbob]

Being overly tuned into the sounds of this car gets real irritating!


Then you best stop modding. Like, now. :) I don't even know why I installed so much stereo crap? I listen, feel, smell, touch, and look at the damn car more than I actually drive it! Normally fine, just always on guard.

Plus I drive by my vacuum gauge as I only get around 11. (You think you hear blower sounds..) Not by what gear I'm in, or RPM's. Thanks cams. Haven't looked at the speedo since last time I got lit up. :D

Modding can take its toll on ya.




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