The exhaust has def. been getting deeper and deeper the more i drive it...around 2,000 miles i started to notice the backfire but only after maybe 30 miles of driving...now it gets very deep just a cpl mins after driving....i finally got a clip of it thanks to my friend (also on the forums, (g356spd06)..my car is auto (ya i know ) and he has the same year, '05 but the 6spd..he drove my car for a little today and said the exhaust is way louder and is much deeper..the clip doesnt do the car justice...(its better when driving with the windows down, and not listening to it thru a camera phone)...anyways what im gettin to is, does anyones stock exhaust sound like this/backfire?

 

lol that either not stock... or something is wrong... since you say it IS stock, i would say something is definatly wrong...

 

Check for a hole somewhere in your exhaust...

 

Sounds like a Stillen exhaust on that sedan. Did you buy it used??

 

I think it sounds sweet! What's the problem?

 

I drove an auto once and it did sound a bit louder than my 6MT. I, for one, don't hear anything out of the ordinary on that vid. Backfire is normal after hard driving too.

 

Revving in neutral or letting off the gas under load at a high rpm can cause mild backfires, especially on 05+ G35 sedans since they have very small resonators compared to previous 03/04 G35 sedans. Most likely the reason the exhaust sounds louder in your auto is because the 05+ autos have completely differently intake manifolds than the 05+ 6MTs. The 05+ autos have longer intake runners therefore the induction noise (and exhaust) will naturally be louder.

 

That sounds just like my G sedan. Every time a friend would ride with me for first time they would always ask if I changed to aftermarket exhaust system. I actually like how it sounds.

 

wow, mine was getting deeper by the mile but nowhere near that loud...dont get me wrong it sounds good, almost like my HKS.....but not as deep.

 

lol no ive had it since mile 13...

thanks for the input guys...the car does backfire but not after hard driving..just maybe 5 mins of driving...

daveB...what you said makes a lot of sense..but sometimes im not even revving and just driving and it will backfire when it goes from 1->2nd gear...also if i rev just to 2.5 k it will backfire too..but what you said about the intake does make sense..my friend with the 6spd said mine does have a better throttle response...its nuts..anyways im not complaining at all..i LOVE it lol..esp considering its completely stock and def louder than a coupe...i should get a video of me driving too..maybe better quality this time...the thing is i dont know how much deeper it will get/is it natural to be this deep?