One not is the normal Z sound, just a little more growl because I have a TurboXS catback.

The other is the z growl but much deeper and throatier.

Somedays the car will be one note, another day it will be the other.

Alot of the time if i bring her up to around 6k in gear when shes throatier sounding, the exhaust note will then switch over to the less loud note.

Its really strange and thought it was all in my head, until my girlfriend commented on it to me one day, saying my car is louder somedays then others.

So I'm lost, haha..

btw, '07 base w/ 6700 miles. no codes. no stuttering.

 

I know exactly what you mean! My Injen sounds louder some days than it does on others as well. Perhaps it has something to do with the difference in atmospheric conditions from one day to the next.

 

I know what you mean also. One day my hks sounds close to stock, then the next it sounds louder. Maybe air temp has something to do with it. Maybe we are all just nuts.

 

i get that sometimes too, and i'm on a stock exhaust :X

 

so its not just me! haha

 

Its the ECU changing engine operation parameters around.

 

do that means its faster on the louder days, right?

 

"Sorry man I dont want to run today, my car isnt loud today" lol

 

I don't know if louder is more powerfull, but I do know the ECU is constantly playing games with the timing, fuel and cam maps.

Cam maps probably have the largest effect on sound.

 

^
Not to get too OT, but would a piggyback or reflash minimize/eliminate this?
[e.g. Utec]

I've never really noticed much of a tone difference [probably more evident with louder aftermarket exhausts], but actual day to day performance seems to vary significantly with my Z. This sounds like a probable cause.

 

I have noticed a difference in day to day performance; even with similar ambient temperatures+/-3 degrees. I think the ECU is causing this based on driver input and conditions. it seems a bit of spirited driving brings her up to speed.

 

I have noticed that some days my car is alot faster than others as well... Sometimes I'll pull out of my development and go.. whoa! I havn't noticed a different tone to the exhaust, I have a custom cat back w/ hi flows and headers it's just really loud all the freaking time.

 

My car switches sounds at 4k rpm. from 1k-4k its deep and clear, from 4k-7k its raspy and higher pitched..

 

same here, i have hks btw

 

Same hear With My Greddy EVO2

 

I thought i was the only crazy one. Yup Injen exhaust louder on somedays

 

Exactly.

 

haha, everyone seems to be coming out of the woodwork on this one, well im happy to know its not just me!

 

Does this ECU adjustment apply to the VQ35DE as well?

 

I do not believe the DE has adjustable cam maps, which are apparently the primary cause of the note difference.