Hey all.

This is lifted from a thread I wrote a few weeks back about a tune-up I did on my car and how the exhaust sounds different afterwards.

The long story short is, I did a tune up on my car:

New OEM drop-in air filters, OEM Denso spark plugs, MAF cleaning, TB cleaning, engine oil change, etc...

After all of this, my exhaust now sounds different. The previous owner put on a Magnaflow exhaust, stock cats but new piping from there and it sounds great. Sounds tuned like a G35 should, just a little louder.

After doing this tune-up, once my car hits operating temperature, around 5 minutes of driving or so, the exhaust will become raspy. I can literally hear the tone change to a slightly louder one mid drive, and when I come to a stop and take off the sound is deeper, raspy, and less tuned.

Does this make sense to anyone?

I have driven about 400 miles since I did this tune up. I did have the battery disconnected for about an hour but I did the idle air relearn and ECU reset (which I believe the disconnected battery did anyways) and it has not gone back to that tuned sound. The car runs better than before, stronger, way more stable idle, so I can't imagine its a bad spark plug or something.

I find it weird that when I cold start the car, it sounds fine, sounds like it did the day I bought it, but after it warms up, it just changes.

Any input is appreciated on this, thanks!

 

Maybe that is how it was supposed to sound? I'm curious as to why it changes though. You should post a video of the sound when you start driving and after the sound changes.

 

The consensus is just that, that maybe this is what it is going to sound like.

I have a hard time believing that tho because it never sounded like this before. Also, the fact that it sounds normal during the cold starts is quite odd to me.

It's by no means a bad sound, if anything it made it unique since it lost the typical tuned G35 350Z sound and assumes a more American muscle car sound.

But I would prefer the former.

My only thought is that a new ECU mapping takes over once the car warms up, and in doing the +/- on the air/fuel, or timing, whatever, it has this affect on the exhaust.

The odd thing is, no one has ever heard of this before. If the car was running bad, or if it made this new sound at all times, I could say, something is wrong, I coincidentally broke during the tune, etc... but that is not true. The car runs fantastic, but only changes the sound of the exhaust after it warms up.

I may try to get a sound clip, although we all know how sound clips go.

 

Sounds to me that is the sound of a clean engine. Would love to hear a video to see what your talking about.

 

I will try my best and grab a sound clip. If they sound different I will definitely post it.

My last thought it to either just get used to it, or take it to Infiniti.

This car has had computer issues and I think that is what is causing this so I they would be my last option.

I'll post back later.

_Michael