I have had my 6 MT for about 1600 miles. Engine seems very strong but seems a bit rough, especially after 3500 RPM.
Gas mileage is pretty good.
Is this something that will get better with breaking-in?
Would switch to synthetic oil help?
How about a ECU reset?

 

Ask dealer to drive another car for comparison.

 

It's just a rough engine. It'll continue to break in and will start to smooth itself out around $10K miles and above. Still won't ever be whipser quiet though. ECU reset is primarily for auto drivers.

I bought a hoodliner to quiet down the screaming a bit, and it definitely helped curb the whailing down when shifting over 3500 rpms.

 

1. The ECU in the 5AT and the 6MT are different, so the characteristics of the engines are different. The 5MT also has components that changed for '05, and the 5AT has a holdover engine. Apples and Oranges.

2. The hood has a liner. What did you add?

3. IMO, the engine sounds so sweet, why would anyone want to hide it?

Lou

 

The VQ motor is not the smoothest running or sounding motor out there. If the car runs good and gets good mileage then I doubt there is a problem unless it's really rough. The best bet is to compare it to another G35 to see if it's normal.

 

The OEM hoodliner is just a piece of cardboard basically. This is a noise-reducing hoodliner from www.b-quiet.com and it does a nice job of quieting things down ... just a little bit. Learned about this stuff when I was researching dynamat to quell the road and tire noise. It also has insulation qualities, so keeps the hood from getting too hot, which I guess is a bonus? Not really sure.

 

I gotta get my hearing checked, my 05 6 spd makes the sweetest hum when I shift over 3500 rpms, in fact that the engine sound is one of my favorite things about the car. I hear screaming and whailing out of my wife but not my engine.

 

Good one. I'm suprised you have not tuned that out already.

 

Noise when being driven at high speed is normal. This is true of G35 and, um... other things as well.