Hey guys I was wondering if someone can chime in on this.
Any help would be appreciated as there are only a few more things I can think of.
Everything was fine with the car before I changed the clutch.

So this past summer, I changed my clutch out to an Exedy Stage 1 Clutch with an Exedy Chromoly Flywheel. After putting the car back together, Ive had compression surge at peak boost going WOT and found out I had a massive boost leak. I did a BLT and found out the throttle body seals were bad, so I changed those out. Since I had the UICP off to get to the throttle body, I took the opportunity to install an ETS Stock Route ICP kit and an oil catch can. After putting it all together, I did another BLT and found out that I had a leak in the fuel injector seals. I needed my car to get to work and school so for a week I drove my car around and noticed there was a flutter noise everytime there was pressure in the system. Whether it was at low or high RPM, everytime I let off the throttle and there was pressure in the system, there would be a flutter noise. I then changed the fuel injector seals and after doing another BLT, I was able to hold 30PSI with no leaks. However, the flutter still remains.

I havent changed out the BOV yet. Its the stock one and I havent suspected it since it was fine before I changed my clutch out and now the car has a flutter sound. Also there has been a lifter tick noise after I did the last BLT. I did remember to remove the oil cap before doing a BLT.

So does anyone have an idea of what could be causing this flutter noise? Ive searched the forum and found a thread with a similar problem, but there wasnt a posted solution. Car is a Lancer Evolution IX and its pretty much stock. Stock block and turbo and Im pretty sure the cams are stock as well. Stock BOV. Upgrades are an exhaust system leaving the exhaust manifold stock, AEM Intake, oil catch can, ETS Stock Route Intercooler Piping Kit, unknown MCB, and a tune from the previous owner. The last time I checked, there was no shaft play. I didnt check for shaft play on my last BLT. I forgot to do so. I also havent been driving the car. Just starting it up from time to time and around the neighborhood but thats it as I am afraid Ill damage the turbo or something else.

Once again, any help would be most appreciated and Happy New Years guys!

 

Any vacuum leaks?

 

I thought there might be one, so I tested for vacuum leaks with carburetor cleaner and I didnt get any leaks as a result. I followed the vacuum diagram in the service manual. I tried to use a smoke machine too, but the one I borrowed mightve been out of smoke since the smoke wasnt too dense. So I kinda did one with no leaks as a result. Im gonna do another once the shop I go to gets a new machine in.

 

And I had a BLT for lunch.

I promise you it's not the new C l U t C h, what else did you change? Use real words not frickin acronyms please. I don't think I'm the only one that's going to give up on reading that entire post of yours.

 

I'm sure he meant boost leak test= blt?

 

The stock BOV is known to leak at 26+ psi. You should consider crushing your BOV or swapping for one with a higher spring rate to handle your 30psi. If nothing else appears to be leaking, you should definitely rule out the BOV.

 

Thats another thing that made me wonder. Ive read many times that the stock BOV starts to leak when introduced to pressure around 26PSI and up. Before changing out the clutch or having a boost leak, the car ran fine and the BOV was able to hold the pressure with no problems. It didnt leak and its a stock BOV thats not crushed. The BOV was able to hold 30PSI with no problems during my last BLT so thats what made me want to rule out the BOV. Another thing that makes me want to rule out the stock BOV is that the flutter happens even when letting off the throttle at around 3k RPM. So if it was the BOV, its slightly stuck open? Thats what I was thinking anyway.

 

Since the OEM BOV uses a spring to regulate boost pressure, going over 26psi may stretch that spring and weaken the force it has to hold boost. Flutter when going off throttle usually indicates a spring with the wrong amount of pressure in the BOV. The excess boost is getting blown off and the spring is either too weak or too strong to release the boost in one burst.

 

just tossing this out there....have you verified that the bov was reinstalled in the proper orientation, not backwards?

 

Makes sense. I dont know much about the operation of the OEM BOV, but if I have to theorize something, I want to think that if there is too much pressure for the OEM BOV to handle. itll just start leaking air under load. If there is too little pressure in the system, then there wouldnt be enough pressure to fully open the BOV and air would slowly have to come out of the BOV causing the system to flutter. Thats what I would like to think anyway.

Unless I always had some kind of leak from my BOV. If so, its weird that it would only be noticeable now.

Lol yeah I made sure the BOV was installed correctly. Thanks for throwing that out there.

 

Hi,

Only way flutter could be remotely related to the clutch would be if the clutch was slipping pretty bad to where it would not make enough load to build boost, but then this would mean that the car would really go no where. Now since there would be a working clutch now, load would change and you would have part throttle flutter from the bov not opening fast enough. This case is very unlikely.

Most likely you just forgot to install the vacuum source for the dv or are getting an incorrect source for the dv.

 

Oh no I never once did think that the clutch was ever related to the problem. I just stated that this all happened after changing the clutch because its something that happened out of the blue. I was thinking how this could happen when all I did was change the clutch, which didnt really have anything to do with the clutch. Well, besides me removing the ICP and intake system to get to the transmission. Thats all I could think of thats related to the clutch change, but yeah, never once did think it was the clutch.