[Kilser]

So to give some context last summer I pulled the engine, did a bunch of maintenance and went full bolt on. So intercooler, inlets, downpipes and so forth. I finally got the chance to drive it and I have a new issue im not sure to think about. I have a theory on why it happened but it still shouldnt be a issue I think.

So first things first I have a video of the noise. The noise only happens on WOT once the JB4 chip is activated. I have a mhdbackend flash stacked ontop of the jb4. When the jb4 is not activated it doesnt have the issue.

Attached is sound of noise.

Video:

Now at first I thought it was the BOV but upon inspection the BOV is closed when this noise happens. I took the air intake off to check and I saw after letting off the gas I have back-pressure come out of the inlet. Not sure if this is normal or not so maybe you guys can shine some light on that.

Now heres where I think I screwed up. When I pulled the turbos I decided to throw some new CHRA's in (Vargas Turbos) and rebuild the wastegates. When I rebuilt the wastegates 1 of the flaps was welded slightly off. I cut the actuator arm to allow it to fit and work and I positioned it so it does open and close with function. Im guessing I shouldnt have screwed with the actuator arm because it opens and closes using vaccum and certain vaccum pressure opens and closes the wastegate to a extent, meaning that its not ON or OFF but it can be opened slightly correct?

Its weird though because when the jb4 isnt activated there is no issue and the car runs fine, keep in mind the car runs fine either way but once JB4 is activated it has the issue of the weird sound.

Am I missing something here? Or should I be pulling the turbos and getting new wastegates / actuator arms and re doing them.

[Jaronbwall]

This sounded like a big project. The fact that you had to cut and re-weld the turbo exhaust actuator is crazy. The length of the rod (changes the angle it opens), duration it's open, and durability is all critical to the performance. I'm pretty sure it's designed to shut 100% or open 100%. I would never DIY any part of a turbo but that's just my opinion.

The only way to tell if you have a boost leak to run some logs and look for codes. The performance of the car may feel "off" but just looking or listening for sounds doesn't tell you much.

[Kilser]

Originally Posted by Jaronbwall

This sounded like a big project. The fact that you had to cut and re-weld the turbo exhaust actuator is crazy. The length of the rod (changes the angle it opens), duration it's open, and durability is all critical to the performance. I'm pretty sure it's designed to shut 100% or open 100%. I would never DIY any part of a turbo but that's just my opinion.

The only way to tell if you have a boost leak to run some logs and look for codes. The performance of the car may feel "off" but just looking or listening for sounds doesn't tell you much.

I cut off the waste gate arm and took out the bushing and put in new ones and welded them back together. The actuator arm was slightly off so I couldn't connect it unless I cut it off and then it would connect. It still was in the correct position and like I said it has zero issues unless the jb4 is connected. Doing some more thinking I have a slight feeling the silicon lines replacing the factory ones going to the inter cooler and into the charge pipe might be leaking. Only happens when jb4 activates and my guess is the few extra lbs in the lines allow the silicon to expand and thus it leaks out under high boost.

I am going to use the jb4 tomorrow and move the wastegate arms around via off the dash and if it doesnt react my guess is its a boost leak from a line somewhere. Any other ideas or what I could be missing?

[Jaronbwall]

I would for sure replace the lines! They crack and leak all over the place after 100K miles. My car is at 103K now. Did you do the intake vacuum line mod?? It helps with the boost flow from the intake to the BOV/charge pipe. It's a restriction point.
You break off the nipple, drill it out, tap threads, and install a 1/4'' metal hose barb.

[Kilser]

Originally Posted by Jaronbwall

I would for sure replace the lines! They crack and leak all over the place after 100K miles. My car is at 103K now. Did you do the intake vacuum line mod?? It helps with the boost flow from the intake to the BOV/charge pipe. It's a restriction point.
You break off the nipple, drill it out, tap threads, and install a 1/4'' metal hose barb.

Have done that already 😂.
Also replaced all the vaccum lines with nice blue high temp lines.

[mifesto]

sounds like you have a massive boost leak. mine sounded like that until i found a leak with pressurized smoke test.

[Kilser]

Originally Posted by mifesto

sounds like you have a massive boost leak. mine sounded like that until i found a leak with pressurized smoke test.

Found the boost leak, like my hypothesis a hose clamp hacked itself off slightly and would only leak under high boost. Swapped to VBand Clamp and it’s now fixed. Thanks for the suggestions!