Recently my car has been making more and more spool noise, I know I know, talk about a good problem to have. It started as one corner that at low speeds in second gear I could really hear the spool noise from the passenger side (mostly because it echoed off a retaining wall on my way home from work).

Now its progressed to the point where I can hear very noticeable spooling noise (or what sounds like spooling noise) as low as 2k RPM on the open road.

The car has what I've been told are stage 5 UMW ZC turbos and a militek exhaust w/ cats, headers, stock airbox, upgraded turbo hoses / intake tract, and 74MM IPD plenum. Its running a custom MAFless tune from Sam that yields 1.2bar.

The car still pulls like a freight train and beyond the excessive spool noise from what seems like the passenger side there are no other issues. It does smoke a little bit on startup if its been sitting for a while (what car doesn't?). I'm just wondering if this is indicative of an imminent failure of some kind or normal and it was previously not working normal. Going to pull it apart this weekend to see if any hoses came loose / do a pressure test. I also have a new set of DVs to swap in.

This video does a good job of capturing the noise, in person the spool noise is even more pronounced.

 

1.2 bar of Boost isnt that much, so i guess your turbos can overpump a leak. Check your Car for boost leaks First.

 

That's what I was thinking, and besides higher IATs I don't know that I would notice it. Like maybe a pin hole in one of the hoses could cause that noise.

one area that seems prone to this is the hose that connects from the turbo outlet to the intercooler inlet, comes dangerously close to the screw that holds on the end of the bumper cover.

 

Sounds like turbo intake noise, not boost leak (air escaping) noise.

My bet is that something (likely the wheel/tire) on the passenger side has rubbed a hole in your turbo inlet tubing.

 

Lol mines even louder than that normally. With stock turbos. Whistles like a dump truck driving around.

 

Could be air density changes that you are noticing. Hot weather really thins out the air and the turbos have to spin up more to meet boost levels. Are you in the desert or mountains?

 

Check the headers too. If they're cheaper ones that may crack it would accentuate that noise.

 

Just replace the Turbo badge with a Kenworth logo, and call it a normal sound....
But, I agree from your video that it does sound unusual for our cars.

 

Southern CA, it was quite hot that day.

I'll have to check this out, the car does have headers that came with it when I bought it.

I'm at a standstill so far but I will update this thread with what I find. Other projects are distracting me atm.