2000darkZ

I have a 2000 Z28 m6. It's a heads/cam car (patriot 243's, comp 224 cam). Made 389 on a conservative tune. I'm getting this weird "rattle" like noise when I'm under load around 3-3500k rpm's. I've noticed it in 2nd, 3rd, and 4th. It does not make this noise if I rev it in neutral or if I push the clutch in. It's a really weird/hard noise to explain. Like I said only does it under load. And it's pretty load, I can hear it echo off walls/cars on the highway. And help as to what this could be would be appreciated, thanks.

joecar

Are you sure it's not spark knock (pre-ignition, detonation)...?

JC316

iTrader: (1)

Really need a video of the noise. Does it get worse when you turn? I am having a similar issue to you and I think I have it narrowed down to the power steering pump. Mine sounds very much like an idler pulley when it starts going bad.

2000darkZ

See I'm not sure. It has ran through my mind though. How exactly would I narrow it down to that?

2000darkZ

It's hard to get a video. Only think you can hear in video is all exhaust at 3k rpm's accelerating. Haha

joecar

Does it sound like popcorn popping...?

2000darkZ

Not exactly, more of a clatter almost.

2000darkZ

I should also say it doesn't make the noise under half throttle either. Half throttle or more, yes it's there. Like I said around 3-3500

2000darkZ

Anyone...

gagliano7

Did you check and make sure your exhaust isn't touching somewhere under load?

joecar

Loose flywheel bolts or pressure plate bolts.

HappySalesman

iTrader: (3)

Sounds like knock to me. Best way to see if its knock is check the knock sensor from a scanner.

2000darkZ

Yes it's not exhaust. That's first thing I checked.

2000darkZ

Hmm didn't think about that. Have you experienced this before?