Stage 2, Cobb Big SF intake - 2 questions

So I've finally reached my modding checkpoint for awhile...

3" Downpipe installed
Cobb Accessport and stage 2 tune
Big SF Cobb intake
Southbend stage 3 drop in clutch

as well as recent intake manifold replacement (under TSB)
and valve cleaning by dealership (the walnut spray or whatever)

Car is running strong, but I've noticed 2 things...

1. There is a very prevalent whistle / howl / beep (like the flatline sound) from under the hood at about 4 through 5k rpm WOT. Not gonna lie, it sounds kind of awesome but not sure if thats normal with this intake?

Video of sound: https://drive.google.com/open?id=1EI7UyHStqJpGNowLo_x5gPPcD7MFwNe3

2. It seems to have a LITTLE surge here and there especially at around 3k rpm light to medium throttle. It's not huge but It feels like it can't decide if it should be in boost or not. (first TC car - not familiar with behavior of a turbo)

Feedback would be awesome.

Thanks

My Unitronic intake and stage 2 tune whistles way louder than that.
It’s normal for these turbo beasties

Are you talking about the turbo spooling up?

Sounds like the typical resonance whine you get from some full length intakes. Some people have said a gfb DV+ solves it but I guess it depends on your setup.

I've got basically the same setup sans the clutch disc. I also get the surging around 3k, I think it's just the tune. I'm going to be going stratified once I get my clutch/LSD and other parts installed. If you already have the accessport there is no reason not to really.

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snidehockey said:

So I've finally reached my modding checkpoint for awhile...

3" Downpipe installed
Cobb Accessport and stage 2 tune
Big SF Cobb intake
Southbend stage 3 drop in clutch

as well as recent intake manifold replacement (under TSB)
and valve cleaning by dealership (the walnut spray or whatever)

Car is running strong, but I've noticed 2 things...

1. There is a very prevalent whistle / howl / beep (like the flatline sound) from under the hood at about 4 through 5k rpm WOT. Not gonna lie, it sounds kind of awesome but not sure if thats normal with this intake?

Video of sound: https://drive.google.com/open?id=1EI7UyHStqJpGNowLo_x5gPPcD7MFwNe3

2. It seems to have a LITTLE surge here and there especially at around 3k rpm light to medium throttle. It's not huge but It feels like it can't decide if it should be in boost or not. (first TC car - not familiar with behavior of a turbo)

Feedback would be awesome.

Thanks

Click to expand...

Did you ever fix this? That whistling would drive me absolutely nuts!

no. I've read that it might be the bypass valve but haven't been daily driving it enough to really get too annoyed by the sound.

As for the surging, that was 100% fixed by the "air flow straightener"

snidehockey said:

no. I've read that it might be the bypass valve but haven't been daily driving it enough to really get too annoyed by the sound.

As for the surging, that was 100% fixed by the "air flow straightener"

Click to expand...

What "airflow straightener?" Can you send me a link?

Since I have the same COBB SF/Downpipe setup, I think I know where the stupid whistling is coming from. Note that I was Stage 1 before with NO whistles. Now I get whistles...

Were you able to insert the PVC valve plug COMPLETELY into the intake pipe? I cannot since the COBB intake pips bung is smaller than stock!!! I am only partially in and you can still see the rubber o-ring. I was racking my brain trying to figure out why it would not go in. Finally, I put a digital caliper to good use. The COBB intake pipe bung is roughly 1.5mm SMALLER than the stock pipe bung. I will be calling COBB about this as I thought their hardware was "flawless" which is why I went with them in the first place...

I'm a wee bit surprised that this stupid pipe installation gave me MORE fitment issues than the COBB downpipe installation!

Air flow Straightener

http://www.treadstoneperformance.co...yComb+MAF+Mass+Air+Meter+Airflow+Straightener

I have same noise, COBB SF/Downpipe setup, and also the Treadestone air straightener. I am calling COBB today about the noise and wondered what COBB said when you called them a year ago. I've heard a few people have gotten replacement intakes, but can't verify.

I'm wondering if the pipe bung size is causing the problem with my setup as well. If COBB isn't helpful, then I'm going to buy a new intake and hope it's not too loud and fixes the problem.

GFB DV+ here, that was the cause of the boost leak, wondering if I should replace that, but it holds 21 pounds of boost just fine. Hope an airbox swap will do the trick.