A couple of days ago I installed an Agency Power short ram intake and turbo suction pipe. The suction pipe has a slightly larger diameter and the BOV recirc bung is at more of a "with flow" angle into the pipe. I still have the OEM BOV. Since this install I have noticed that when I let off the gas there is a flutter sometimes. Almost sounds like the BOV is opening and closing rapidly and weakly. I am hoping this isn't compressor surge. It seems like it does it at lower RPMS like when I am inching forward at a stop light or something.

When I rev it up pretty good you can hear a good whoosh like the BOV opens proper and strong. Maybe, because the turbo is spooled up more and has a higher discharge pressure when the throttle closes.

Anyway, do you think this is just the BOV opening at a lower discharge pressure or something like that due to the lower RPMS when it occurs?

 

i had the same problem after i installed my AEM intake. its not the BOV because i purchased a turbosmart bov and still does it. I completely redid the install, sounds like something came loose and sound went away. the same day i had a tune so the tune might have fix it also. if that made sense.

 

its normal, fluttering happens even in stock form, it is just less pronounce since the intake is box type. It shouldn't hurt your turbo...I wouldn't stress about it, but a tune should get rid of it.

 

Part throttle compressor surge. Totally normal, completely harmless.

 

Same sound with the AMS Intake.

 

Surge is the situation when the compressor "spits out" more air than the engine can swallow, which causes a backup of air at the intake and it actually creates reverse-flowing pressure waves that can be very damaging to the turbo. You want to avoid surge at all costs.

 

Thank you all for your help! I appreciate your replies. I find more and more for a newbie to this stuff like me, this community is an invaluable resource. This is in thanks to the community members for being obliging to a person like me who probably asks pretty basic stuff compared to most off ya'll's knowledge. Thanks again.

I reinstalled my OEM intake system and removed the air filter and left open the "box" so I could hear any noises. I found that the "flutter" did persist. I then wrapped some plastic around the opening where the slip in filter goes and observed the plastic when creating the "flutter" occurance. The bag indicated a back flow from the turbo WITH the factory intake pipe and MAF housing, etc.

This tells me that even with the factory systems there is a "surge" in these lower RPM (partially open throttle then closed) situations.

Is this an observation that others concur (I'm not sure how to spell "concur") with? If so, does Mitsubishi have any communications about the problem? I talked with my dealership and they "have not heard or observed this" problem. I also looked on Mitsubishi's various sites and found nothing.

In a side note, the only other issue I have with my AP intake is that the BOV ends up pressed against the upper intercooler pipe. It's not a big deal, but eventually I want to upgrade this line. I am afraid this BOV positioning will cause problems for fit. I was thinking of repositioning it to be near the front of the engine compartment where the outlet is horizontal instead of vertical and down. So I would have to get a different hose for the BOV outlet so that it curves down into the bung on the intake. Any suggestions on vendors would be great. Also, any advice on if this would negatively affect integrity or performance.

Thanks.

 

^^^^
I have the agency intake as well as agency bov and uicp. I originally did what you are talking about and moved my bov to the front below the intake... bad idea. I had to move it back because in order to get a good custom tune I had to recirculate. The only way for this is to keep it where the stock one sits. I had to buy a new bov return hose from agency to fix my bad mistake.... So if I were you I would leave it. I will get a picture of mine up and so you can see it.

 

That would be cool. I would like to check it out.

If I did move it, i was thinking of finding someone who could manufacture a return hose so that I can recirc. the BOV vent even if I move it.

 

A little flutter/surge at part throttle is normal. Surge at WOT is when you start to have problems.

 

The bov return I bought from agency