Do You Have Blower Rattle?

[Rizzo]

As long as the rattle is at idle, it is considered "normal" by GM

http://www.camaro5.com/forums/showth...r+supercharger

[rextremeak]

4500 miles. No rattle. Only rattle I have is when my clutch is depressed and I'm rolling down a bumpy street. Anyone know what that is?

[jsd]

What you mean with rattle, which kind of rattle?

I have some noise when i depress my clutch, but just in the 1 gear.

I have 5500 km on it. Its from the beginning and its no louder then before

[VegasZL1]

I thought I had blower rattle. It was driving me crazy. I finally took it to the dealer and after two days of diagnosis it turns out that the rattle was the lines for the diff cooler rattling on the exhaust.

[BlemsBumble]

Nothin' yet but I'm expecting it to happen. Pretty common with the LSA, I hear.

[rextremeak]

Originally Posted by jsd

What you mean with rattle, which kind of rattle?

I have some noise when i depress my clutch, but just in the 1 gear.

I have 5500 km on it. Its from the beginning and its no louder then before

Mine sounds like a rattle/clunking in the driveline somewhere. Only hear it when rolling with clutch in and on a bumpy road. As soon as I re-engage the clutch the rattle stops.

Anyone else have that problem?

[morgnstern]

Just went over 500 miles yesterday, I have noticied it since day two at idle and low RPM. I think I just can't hear it when moving but it is likely still there, however it isn't always there, just usually. I thought it was lifter tap before reading all of this.

[Chevrolet Customer Svc]

Originally Posted by rextremeak

4500 miles. No rattle. Only rattle I have is when my clutch is depressed and I'm rolling down a bumpy street. Anyone know what that is?

If you feel this may be an issue, the best thing to do is to get a diagnosis at a dealership as they are our eyes and ears, so to speak. Please let me know any outcomes or updates.

Brandon
Chevrolet Customer Service

[SlingShot]

Originally Posted by rextremeak

Mine sounds like a rattle/clunking in the driveline somewhere. Only hear it when rolling with clutch in and on a bumpy road. As soon as I re-engage the clutch the rattle stops.

Anyone else have that problem?

That's from the throw out bearing and slop in the drive train, the SS is the same way ... Normal so no worries there

[Mr. Wyndham]

I found this a while back on LS1tech...and together with a brief conversation with Al O about it all...I'm not worried. I don't hear the noise unless my hood is open and I'm darn near resting my head on the engine cover...

I don't think it's much of a secret that I have a profound respect for OE engineering. It's not always perfect, but they manage to achieve that "balance" that I value so much. I think this is a perfect example of that.

The nuts and bolts of the below is pretty simple: If you can't hear it with the hood down, then it's normal operation. Yes, it's designed to do that, because in actuality, testing proved that a solid coupler made more noise. So my .02 is that this is more an annoyance than anything.

Post on LS1tech.com
November 23rd, 2009

"I’m Ed Piatek and I’m the Program Engineering Manager on the CTS-V. I recognize that this forum represents the thoughts and experiences of some very passionate owners and enthusiasts, and appropriately many of us on the engineering team periodically review this and other forums to keep our finger on the pulse of this important group.

While we cannot respond or comment on every post or question, the number of comments and degree of inaccurate information around supercharger shaft wear on LSA and LS9 merits an engineering response to set the record straight, and assuage any concerns of our owners. Here is the response from our engine experts:

The torsional isolator is used in the CTSv LSA and ZR-1 LS9 engine to isolate potential gear rattle noise during idle. The isolator contains a torsional spring that fits over the shaft. Purpose of the shaft is to distribute the stresses in the torsional spring. As the spring goes thru its travel, the inside of the coils can contact the shaft. The spring material is intentionally harder than the shaft which by design results in visual witness marks and/or limited wear on the shaft. The witness marks and/or limited wear is expected and has been observed on all the Eaton component durability tests, GM engine and vehicle durability tests and on customer vehicles with no impact on the functionality of the spring and isolator. The shaft and isolator are in a sealed cavity, separate from the rest of the supercharger and engine.


Q: Will this shaft wear harm my engine?
A: No. The visible wear will not damage the engine. The supercharger and the engine were tested and successfully validated to meet all GM durability requirements…which are much more severe than any customer usage.

Q: What causes this wear?
A: The isolator contains a torsional spring that fits over the shaft. The purpose of the shaft is to better distribute the stresses in the torsional spring and prolong its life. As the spring goes thru its travel, the inside of the coils can contact the shaft. The spring is a harder material than the shaft…so that when there is contact, the spring will not potentially break. If the spring breaks, then the torsional isolator function is lost.

Q: Can the shaft wear all the way thru and broken pieces get into my engine?
A: No. The travel on the spring that is contacting the shaft is limited. It cannot wear all the way thru the shaft. The shaft and isolator are in a sealed cavity, separate from the rest of the supercharger and engine. It cannot be ingested into the engine.

Q: Can worn bits or wear debris from the shaft get into my engine?
A: No. Again, the torsional isolator is in a SEALED cavity inside the supercharger. The seals on the bearings have not been compromised and wear debris is fully contained in this cavity.

Q: Why is the isolator design better than a solid coupling?
A: The torsional isolator does precisely that – it isolates an even more objectionable gear rattle noise that was being heard inside the vehicle cabin at all times during idle. The solid coupling will not eliminate this noise.

Q: My car is now quiet after I replaced the isolator w/ a solid coupling…how do you explain that?
A: If the ONLY modification was the replacement of the isolator w/ solid coupling…then it’s unlikely that it’s completely quiet. Most likely, you WILL have the timing gear rattle noise inside the cabin. Initially, it may sound better because the random “knocking” noise outside the vehicle is reduced…but you’ve now traded that noise for the gear rattle noise. Now…if you also replaced the induction system and exhaust system w/ louder aftermarket/performance parts…then it’s no longer an accurate comparison because you may not hear gear rattle over the increased exhaust and other noises in the cabin at idle. By the way, the torsional isolator is not a serviceable part…and removing the front inlet to replace with another part has warranty implications.

Q: Will GM be releasing a service fix for the shaft wear?
A: No. The current torsional isolator design does not diminish or compromise the durability or longevity of the supercharger or the engine. It has been fully validated to that effect. It also provides a benefit to the customer in terms of reduced noise at idle inside the vehicle…where the driver and passengers will be located during vehicle operation."

[SlugWound]

1300 miles, no rattle yet.

[CAM....ZL1]

5300 mi. on mine have listened several times over several months and as of the last check have not noticed any rattle or abnormal noise. I do however have a problem with my ac - heat - heated seats, and the controls for them. some days they work and some they don't....leaning on
more of the don't side. If car has been modded will it still be covered ?
Yes it did it before the mods. atleast once in the summer, but now its
from one start up to another.

[Mr. Wyndham]

Originally Posted by CAM....ZL1

5300 mi. on mine have listened several times over several months and as of the last check have not noticed any rattle or abnormal noise. I do however have a problem with my ac - heat - heated seats, and the controls for them. some days they work and some they don't....leaning on
more of the don't side. If car has been modded will it still be covered ?
Yes it did it before the mods. atleast once in the summer, but now its
from one start up to another.

If they want to make an issue out of the mods, the fact it occurred before they were installed won't matter because it wasn't brought in to check out.

But...unless you did some major reprogramming, or adjusting the thermostat/heating-cooling components...I can't see how they'd easily relate any performance mod to that.

[ZL1ster]

...only when the hood is up.

But isn't this a question of 'when' not 'if' we hear the noise because of progressive wear.

AND we're suppose to drink the Kool-Aid of it's okay because we might be able to get a replacement SC...?

Love the car...but not that noise or the fact that hopefully we'll be able to convince swap-out of SC.

In regards to the "noise"...see, "blower snout wear and noise" thread.