Exhaust Vibration Sound While Engine Under Load

[Doost]

Hi Y'all,

I recently installed new Fabspeed headers and a used Active Autowerkes axle back section 3. Sections one and two are still stock. Additionally, I added an Evolve tune. A local shop will be adding in (2) 200 cell cats to section one next week. Things sound great nearly all the way through the rev range while in neutral. However, when the engine is under heavy load, pedal down, I can hear (but not feel) a metallic vibration through the whole rev range while accelerating. I put the car up on a lift, and engine revved several times while one of us were underneath and we could not find any rubbing of exhaust components/heat shield. However, while driving, to me the noise sounds light/tinny like a vibrating heat shield.

So I'm wondering:

• Is something changing in resonance while the engine is under load that could be creating this noise?
• Is it possible that additional back pressure from adding the cats could solve this?
• Could the used muffler, while under load be the culprit (loose baffle/etc?)
• What else could I be missing?

I'd like to isolate the problem before adding another component (cats) if possible, and just wanted to check if anyone has experienced a similar problem after headers install.

Thanks!

Dustin

[Doost]

Took off muffler and took quick spin with out one. Same vibration noise. 99% sure it’s a heat shield problem somewhere. I had assumed that any heat shield noises made while accelerating in motion could also be heard while parked in neutral

[Cubieman]

So the heatshield above the headers is 100% not touching?

[Doost]

Cubieman its possible- the first thing I did was check to make sure the two heat shields above headers weren’t touching each other- but I didn’t confirm if lower one was touching headers. The sound seems to be coming from behind me, but it could be transmitting. I’ll definitely double check this first tomorrow before climbing under the car again

[Dr23]

Doost did you resolve this rattle?? I have very similar noise coming from my M3