Compressor Surge? Flutter? 16t Hybrids

[Zbottoroff]

Hey ya'll i have a 2010 e92 n54... has 121xxx miles on it. Just recently went fbo and upgraded the turbos & now i am having a surge/flutter and air coming out of inlets.
mods list includes...
~Ebay 16t Hybrids w/tdo4
~5" ARM FMIC
~Catless DP
~Tial Q BOV w/ VS Tmap Bov line adapter
~BMS DCI
93 octane w/ MHD custom tune running 20psi boost
If i am on throttle at 1k-3k rpm it will make air noises from the inlet and from the bov.
If i use MHD wastegate fix and go all the way to the left for less rattle then my wastegates rattle like crazy and i still have the same noises.
There are a few forums that i have read with the same problems but they are all a dead end from 2013 and no one will respond to let me know if & how the resolved the problem.
Maybe afr or bad wastegates? Maybe bad turbos? I have no issues hitting boost target. Although my boost does oscillate from time to time.

 

[Slowagon54]

Make sure you have the correct BOV spring installed first.

 

[Zbottoroff]

right now i am running the white spring and the bov is open at idle, and the black spring is on order and should be here soon... but i honestly think it could be something other than the spring.

 

[doublespaces]

I've seen/heard of people having strange symptoms which appeared to be a tuning issue so if you don't have a boost/vacuum leak then perhaps have the tune checked? Can you upload and share a datalog: https://datalogs.spoolstreet.com

 

[e30gentry]

right now i am running the white spring and the bov is open at idle, and the black spring is on order and should be here soon... but i honestly think it could be something other than the spring.

Why would the BOV be closed at idle?

Like mentioned, check all vacuum lines, do vacuum test, pull vacuum and check actuators

 

[Zbottoroff]

Log-09-12-2020-04-01-25

Uploaded by API.

datalogs.spoolstreet.com

 

[doublespaces]

Log-09-12-2020-04-01-25

Uploaded by API.

datalogs.spoolstreet.com

Nice, you can also copy the BB code from the bottom and embed it:
View graph 43911

 

[doublespaces]

I'm surprised your tuner hasn't mentioned you're logging five timing channels for potentially no reason? You just need to log cylinder 1 as far as I know, and then log all six timing "correction" channels. Perhaps that is out dated or bad information, I could be wrong.

Anyway here are a couple of guesses:
I see throttle closures. If the throttle closes and creates a pressure imbalance between the charge pipe and manifold, if it's bad and fast enough the bov can open prematurely. That is actually the entire function of a bov, to prevent pressure from building up in the charge pipe with a closed throttle blade, creating surge situations.

Something to point out, MHD doesn't have a separate gauge for the manifold MAP sensor and the chargepipe TMAP sensor. Only the manifold sensor will ever see vacuum, and with the throttle blade closed, you could actually have boost in the chargepipe and engine vacuum on the other side simultaneously. So despite there being boost displayed during that throttle closure, that is only an indicator of the chargepipe side of the blade. If there is vacuum building up on the manifold side, that will pull the bov plunger up and it may not even register as vacuum in the log.

Another thing to mention, boost is a calculated value, some sort of model. I don't actually know how it's calculated so I don't know that it can be taken as a literal value. Not a tuner, someone else would need to chime in.

I'd start by fixing those throttle closures and checking with your tuner, that shouldn't be happening unless it's a work in progress.

 

[ShocknAwe]

How do you fix throttle closures?

 

[doublespaces]

Looks like he is over boosting if you look at boost target

 

[Slowagon54]

Like Spoolstreet said, boost is a calculated value. If you are overboosting throttle will close to hit target boost. If you have many TC you should adapt the tune... and the description of the shared map says "16T Base Map..." so i guess its still a map in progress? You should ask your tuner.

 

[Jeffman]

A couple of things:
- The air sounds are likely the spooling of the turbos, possibly air pissing out of the BOV.
-A custom tune can adjust the spooling limit rpm which is typically set between 2500 and 3000 rpm. You are building boost over 3000 and achieving target boost just fine so probably not a boost leak.
- I now recall similar behavior with my stockers. The white spring is 8 psi. if the black spring (6 psi) doesn’t solve it then actually try the plain spring (10 psi) which for some reason works better for me than the white spring.

Also:
- Do your engine a favor and allow oil temps to come up to at least 210F before going WOT. Your oil temp is only 156F, not even moving the gauge on the dash.
- Make sure DTC is off - pressed for three seconds
- WOT is best with the accelerator pressed down 100%

 

[Zbottoroff]

Yes I deff should have let my oil temps rise a bit before getting in the throttle. This is my second tune because I was over boosting in the first tune.
- On cold start I have air coming back through the cones.
- At 1500-2000 rpm I have the same thing happening. Small pshhh pshh pshh pshhhh pshhhh noises coming from the cone as if there is some sort of constant back pressure. I have been told by several friends that they think it could just be bad turbos or turbo. Appreciate the help.. I’ll reset adaptations tonight and look over everything including my o2 sensors and make sure they are all connected correctly.

 

[fmorelli]

This is my second tune.

Note that custom tunes are rarely done in a couple passes. You could do quite a number of revisions before you settle in with a good setup. And as things start to get turned up, we start to run into the performance limits of all the various components. From quality of gasoline to carbon deposits to .... Every motor is different, and I'd expect improvements with further revisions. You may not have an issue to address. TBD.

Filippo

 

[Jeffman]

Zach, just to be sure - the psshh pssh sounds aren’t the air getting sucked into the DCIs? If this is the first time you’re driving with the stock air box removed, that’s the sound the DCIs make and one easily hears when spooling at low rpm

 

[Zbottoroff]

Edit: First video is from today. Second video is from two weeks ago. in the first video if you listen close enough you may be able to hear the noise I’m talking about.

 

[Slowagon54]

Gotta say it again, check your BOV setup. Sounds wierd.

 

[langsbr]

The second video sounds like your BOV might not be opening and causing surge? It sounds like it happens when you let off the throttle. I would get a mighty vac and test your BOV, you want it to be open at 20" of vacuum (10 psi). I think I have mine to open even a tad earlier. You don't even need a new/different spring. If you have a vacuum gauge, just start trimming off of your current spring (very small at a time) until it opens where you want.

 

[Zbottoroff]

I will try that with the spring, when I first did the turbo install I had a Cobb cp with stock dv and it did the same. Just maybe not as bad. I’ll trim my spring and report back with the results. Thanks

 

[Zbottoroff]

This is cold start