Icegod87

2014 Evo X, 12500 miles on it. No mods except for a new stage 3 ceramic competition clutch installed at 11500 miles. Im going to bring it in to the dealer to check it out just to be safe but maybe someone can help me out in the mean time.

In the past 2-3 days ive been hearing this whirring/almost whistle like noise when accelerating in boost during 4th and 5th gear. Doing research its similar to the T-Case sound of death issues that some people have had or the ACD going out. Ive had 0 performance loss, car pulls hard, everything works as it should except for this damn noise. Idle seems to be fine as well, and the noise is there from cold start to fully warmed up, never seems to go away.

I seem to only hear it during acceleration in 4th/5th gear and i think its only happening during spool as i dont think ive heard it under 3k rpms, or when boost is tapering off around 5.5k+ rpms. It does not make this noise that i can tell in 1-3 gears. Or revving it in neutral. And it does not make this noise when i take my foot off the gas, decelerate, or push the clutch in, and it doesnt do it in reverse. it only sounds when i push the gas peddle in 4th/5th.

Link to the video i took this morning at the bottom of this post, its not the best but hopefully someone can identify the issue. For most of the video im in 5th gear, then near the mid/end i downshift to 4th for a small pull or 2. You can hear it perfectly right at about the 13-15 second part of the video.

----Video----
https://www.youtube.com/watch?v=rvfn...ature=youtu.be

ikt

iTrader: (18)

Sounds like a hiss, def not ACD or T-Case. It's probably the factory boost solenoid. At 3,000 RPM in 4th gear under load you'd be like 32psi, but the factory boost solenoid will release pressure over 19psi. It does this by releasing the pressure through a vacuum line that goes to the intake tract. So it's probably that.

Icegod87

Well thats what i was hoping, something intake/vacuum related like a loose hose. However today it seems the noise is getting worse. I think i can hear it now in 3rd gear, and now when i push the clutch in and let the car roll to a stop i can hear this noise all the way to a stop, its not as loud as when accelerating in 4th/5th. But im starting to think it very well may be Tcase or ACD... :/

ikt

iTrader: (18)

i think you just never noticed it before

PSUfan1

iTrader: (2)

I listened to the video several times and honestly I don't really hear anything out of the ordinary (but it's been a while since I've had stock intake/exhaust on). It could be the diverted pressurized air from the boost solenoid I guess - but with a stock air box I'm not sure that you really would hear that.

In any case, sounds like a pretty normal spool to me.

ikt

iTrader: (18)

the OEM solenoid actually dumps right up there just before the turbo

PSUfan1

iTrader: (2)

Yeah I know where it dumps - but I'm not sure that I've ever heard it over the turbo. Given the volume of air that is moving through the intake to the turbo compared to the very small amount that is bled off of the waste gate control line to the intake through the solenoids (and pills), I'm not sure that you can hear that (but as I said it's been a long time since I had the stock airbox). Still worth checking out those hoses to make sure there are no obvious rips or tares though.

I'm gonna listen a few more times.

Edit 1: okay I do hear it now at the 13-15 second part and later in higher gear around 43 seconds. Doesn't sound like air to me.

OP:

Can you take a video with the camera microphone down low in the passenger foot well towards the center stack? Not really sure if this would help... but hey it is the internet.

How much throttle are you giving it?

Did you replace the clutch due to the first one failing / being worn out - or was it just an upgrade? When?

Edit 2: kinda sounds like t-case. Might be worth sending an e-mail to jacks or shep for a listen.