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turbo flutter?


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I just went stage two, and I noticed a tiny flutter noise when building boost to about 5 psi, then it flattens out and sounds completely normal. Still holds boost great throughout the entire range, though. Should I be worried about this? Could it be an exhaust leak of some sort? I'm just seeing if anyone else has had the same issue
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Your other thread:

http://legacygt.com/forums/showthread.php/stage-2-questions-215142.html?t=215142

 

Pull a log already. I explained the reasons why to you. If you think the jump from stock to stage 1 was a greater jump than from stage 1 to 2, that doesn't seem right.

 

And do what with the log?

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For next time try logging:

- The air fuel sensor instead of the air fuel learning, sensor actually tells you the AFR ratio.

- Ignition total timing

 

Your boost error looks to be oscillating a heap during WOT. Not too many changes in the WGDC but boost error is jumping between-0.5 and 2.5 psi a few times in the space of 5 seconds. Sure you're holding steady boost?

 

(ITT is your ignition timing and AFR sensor is your AFR learning)

Capture.thumb.PNG.c9ebec85a768bdba83185cd82f72e346.PNG

Capture2.thumb.PNG.a0a9563f97beddb9bf845f3bbe36b976.PNG

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Did it sound like the clip I posted? How exactly did you tune it out?

 

Honestly I couldn't hear your clip very well. My clip is posted above, you could give it a listen and see if it sounds similar.

 

The Cobb XLE BPV I ran with my FMIC had an adjustable spring, I loosened it almost all the way out to tune out my flutter. Did not get rid of it fully, but for the most part it took care of it.

 

Now I have a PW TMIC and a Forge BPV (Cobb wouldn't fit). Have flutter/surge at certain RPMs/throttle positions. I've just learned to live with it at this point.

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Hey, I see your log, but I have a few questions:

 

1) What gear did you do this in?

2) Start your pull in 3rd gear 2KRPM, and pull to redline. Stay in 3rd.

3) Get rid of Dynamic Advance (degrees), MAF Volt. It should help with the logging resolution a teeny tiny bit. You can probably also get rid of FBKC and FLKC right now and instead use Knock Sum only.

 

The AP has crappy logging resolution so when you log, you really have to select parameters based on what you're trying to get out of the log.

 

Also, I tried listening and I really couldn't hear a thing...

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Are you able to take a learning view screenshot? Your AF learnings are +10% (adding 10% more fuel) at low loads which indicates that the engine is seeing more air than the MAF is reading.

 

Firstly try cleaning your MAF, then check the pre-turbo intake for vacuum leaks where air could be sucked into the intake between MAF and compressor. If that's happening then that could explain the flutter.

 

Your log shows you losing boost twice at WOT within 5 seconds so you're losing pressure somewhere but not consistently as it builds boost a little. No AF learnings at high load though...

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