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Wastegate flutter while accelerating.. (I think)

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24K views 41 replies 21 participants last post by  Vince 
#1 ·
okay guys so just installed an injen short ram intake and i have the factory BOV venting to atmosphere. when I am accelerating and holding about 3/4 throttle at a steady speed I hear a bit of a flutter. keep in mind throttle is open so I don't think it's compression surge. I will include a video I recorded today. I am new to the turbo world so go easy on me lol thanks guys

2013 Kia Optima SXL wastegate flutter - YouTube
 
#2 ·
I don't hear anything......I think you are just hearing suction noise from the aftermarket intake.
 
#6 ·
That noise you hear is the bov. If you look at it you will notice there are 2 hoses connected to the bov. I pressure tested my oe bov and when i put a small amount of pressure it fluttered open frequently. Above 13lbs no flutter. . I think the factory location of the vacuum line should have been better engineered because it is influenced on venturi effect vacuum rather than actual vacuum and i believe this is what causes the issue. All in all, poor design.
 
#9 ·
Use the search bar and see how many topics on "flutter" have been discussed in the past 2 years...
 
#11 · (Edited)
What you are talking about is normal, you hear it around the 26 sec mark?

Here is an explanation already posted:
""BOV fluttter is basically leaking off boost when fluttering. In my Subaru I had, I installed a 18lb actuator that took care of that. But, the Optima sees boost near 18lbs, so something heavier would be in order. They actually make adjustable actuator bars, but doing so would throw off the volts for the ECM, causing a CEL. This would be necessary or achievable whenever there is a company that makes tuning software for the Optima.

The only option you have at the moment is TSB 115 I believe? It has to do with the fluttering and no power at cold starts. My vehicle is in the shop for the second time with this no power at any time now. A boost solenoid will be replaced tomorrow for it. Hope that will be the fix for good.

But, in short a little flutter is normal. A lot of flutter is not.""

You will hear more flutter with an intake, alot of flutter WITHOUT an intake would be the problem the above paragraph is referring to
 
#13 ·
Funny stuff. Everybody just reposts things they read.


Go do testing yourself. Thats what i did, and guess what. I fixed the problem like i said by changing the bov. The dealer is going to give you the runaround, anybody who is just reposting is easily manipulated, and those wyo go and figure out what is going on, and how to fix it are the ones to listen to. Good luck
 
#15 ·
It does sound like wastegate flutter to me. You dont hear it until you put on a open element intake and I have it too. We tried a different source for the bov (completly bypassed the bov solenoid) and it didnt change, then installed a tial bov didnt change, monitored a boost graph while on the dyno and saw no change while it was happening. Its quite common too on the 19t. If you want to get rid of it, weld the internal wastegate shut and weld an external wastegate to your manifold :)

A bov leaking will make the same type of noise, however there is a really easy way to diagnose which you have. The way we figured out it was wastegate flutter and not bov flutter was to leave the bov vta and put the intake back on (with the hole in intake for bov plugged). The flutter was gone because we couldnt hear it through the intake anymore, and the bov was still vta so if it was the bov leaking we would still have heard it.

Hope this helps!
 
#24 ·
I think you guys need my videos to hear the flutter... this is of nilvrod's car

with eco mode and traction on


with traction and eco off
*note* no flutter like in the first video
 
#28 ·
Evil, fyi venturi effect occurs without fluid as well. I see problems with truckers messing with things all the time. There is no throttle plate on a diesel engine, therefor vacuum is difficult if not impossible, and dangerous to measure, but during high boost and no boost conditions(technically no boost would be in vacuum) if a pressure sensor is not clocked correctly, or a boost tube, or egr tube becomes bent at an angle not intended by the engineers a venturi can be created. The swirl action creates a significant rise in pressure for a split second, causing the ecm to believe that boost just went through the roof. This causes a fuel cut, loss of power, and poor fuel mileage because the driver feels the need to throttle through the problem. Many times this occurs because people want to add gauges and decide to tee off of existing sensor locations rather than doing the job right. If the port where our vacuum/boost source came from was at an angle closer to 65 degrees i believe this issue would be completely gone. I had seen the same issue on my 700hp lexus and solved it by using a factory port that was in an area where any type of intrusion didnt effect airflow. Then we installed 1/2 inch aluminum line, mounted a remote vacuum supply canister under the intake, and any additional sensors needed ran off that. It had a total of three lines going to it to ensure it had accurate vacuum/boost at all times.
 
#30 ·
OH MAN, lol, now that there as like 50 Injen short ram intakes sold in a group buy EVERYONE is going to be hearing this for the first time. lmao.

1st, in physics/engineering air is considered a fluid. Everything else EvilMechanic said I agree with though.

Dieseltech, its cool you have experience with poor vacuums on other platforms etc and now you say you fixed it on the Optima, but I do not understand how. You said you simply changed the BOV to an aftermarket and it fixed the problem? If so, then you didn't change the vacuum? and therefore the vacuum wasn't the problem was it? What exactly was done beside bolting on the nameless charge pipe with synapse?

Here's my thoughts & experience. You'll see they fall in line with Evil was saying:
-I have had my BOV in Vent to Atmosphere every since this thread existed over 1 year ago: http://www.optimaforums.com/forum/6...ussion/2765-diy-vent-bov-atmosphere-pics.html
-I also have the Nameless intake pipe connected to the stock air box. This is how they recommend, the gains are all in better flow through the tube, not filter gains etc.... ANYWAY Key thing here is that 1) still running stock BOV vented to atmosphere, 2) still have the airbox to limit intake noise
-I never heard flutter after doing this, EVER....over 1 year
-UNTIL literally 1 week ago... I hadn't touched the silicone coupler connecting the intake pipe to air box in who knows how long and it had come loose. I immediately knew because the intake had sounded very near stock, BUT now all of a sudden I heard spool and air rush annoyingly loud!...
-Paired with hearing this loud spooling noises, when i'd go hard accels i could now hear the flutter!
-Sure enough, I pop open the hood, see a slight separation/gap between the silicone coupler & air box...It was breathing unfiltered, unrestricted..whoops. I fix the connection, go for a drive and all is back to normal. NO NOISE. all that changed was adding back the airbox's noise & airflow restrictions.
-Also like evil mentioned, no driveablilty or boost etc was any different compared to when I heard the flutter Vs. not hearing the flutter. The performance is the same, the boost levels are the same. The only difference 1 way I could hear it, the other I couldn't. Thats my experience driving on the street, he saw and logged the same on a dyno apparently, per his post.

Now, again this happens in WOT or a "hard" partial throttle, almost WOT... Therefore the BOV is closed or at least should be. If you remove the vaccum to the BOV altogether or use a blocker plate, the flutter noise should still occur. Has anyone actually done this? If so, then that'll put the nail in the BOV-being-the-issue coffin....if it magically goes away, then you know the BOV's vacuum plumbing was the issue all along. That test will point you 1 way or the other, not throwing on another BOV to test, etc....Problem is i'm not making my bpv dysfunctional on purpose for this test, lol (surge?)...AND I think i've proved its not the BOV to myself (and evil to himself) by not hearing the flutter on a vent to atmosphere Valves.

So, to be clear theres an off chance it could be the stock BPV vacuum porting that's creating false vacuum with venturi, BUT you'd hear it with the BPV vented to atmosphere and stock intake left alone. You don't though.

SO whats left? 1) compressor surge or 2) wastegate flutter.. I personally think its ECU controlled flutter with our "high-tech" Electronic Wastegate Actuator...The reason is to avoid #1.

This td04hl-19t can spool pretty **** fast. In lower RPM's a 2.0L engine does not have the airflow capacity to "Accept" past a certain amount of CFM. If a small turbo is spooling so early and creating too much CFM for the engine to handle/pass-though (at that specific RPM) then you get compressor surge. (The other way surge occurs is of course when the throttle plate closes on shifts,etc and air bounces back to the turbo compressor, the reason we have BPV/BOVs)....Theres only 2-3 ways to avoid "too much air" type of surge.
You can improve the Volumetic Efficiency of the engine, basically porting, cams, larger exhaust to minimize turbo backpressures...
Or you can reduce boost/air CFM in the lower engine RPMs...
And/Or you flutter the wastegate on purpose with an electric actuator by command of the ECU, to avoid overshooting the boost in the lower RPMs.

So if you're adding an open filter intake be prepared to hear it unless you a) free up exhaust and/or porting, b) wait til 3k and higher RPM to really gun it, c) get a tune with less boost at lower RPMs, tapering up once beyond 3k rpm....and/or d)go get your 19t compressor housing machined for anti-surge vents

and if you can't/won't do any of that & can't take the flutter noise then go back to the stock airbox, with its air & noise restrictions.
 
#36 ·
Total newb to turbos..I have this issue too when i really get on the throttle and let off. I dont mind the flutter. I read all 4 pages of this thread and still dont know if Im ok leaving it be and letting it flutter when I really get on it and then let off, or if I need to go and get someone to look at. Remember class, theres no such thing as a stupid question..lol
 
#32 ·
if its actually surge occurring from too much air verses engine VE at low RPM, then yes. If its just EWGA fluttering, then no.

here watch this video at 1:40 in, you'll hear the EWGA flutter once it hits peak boost, watch the boost gauge needle as it stay where its supposed to be (its the tuned run...1.5 bar = ~21-22 psi)..thats alll good, its what you want to be happening. Its not from the actuator being weak, its being done on purpose by the ECU.

 
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