K04 flutter issues since shop install

[eiresgaus]

Since I had my K03 swapped for a K04, I've been having fluttering noises like pigeons at low boost and the full-on 'stututu' noise at full throttle.

There is also a point on about half throttle where it flutters around 2500-3000rpm, which is about the same point where on the K03 at APR Stage 2+, it sounded like the diverter valve opens (?) and releases some pressure. This is not happening and causes a sort of hiccup and drop in boost under acceleration.

I've brought it back to the shop twice that did the turbo install, and both times they've said it's normal for a K04 and these cars with the way diverter valves work.

Now, I've never heard of anyone living with flutter with their K04. The shop also told me that they don't like the CTS Turbo K04 kits and the way the diverter valve is used with it.

My questions are first of all, should the diverter valve not be relocated towards the front of the engine in the CTS DV relocation kit that the turbo kit came with?

Could these simply be symptoms of a bad DV?

Troubleshooting is not a problem for me but I am not mechanically inclined enough for things like turbo swaps and rather leave it to professionals. These guys are a renowned VW/Audi workshop in my area, and their answer that it's just a lot easier to use the APR K04 seems odd when many other people have used the S3 K04 from CTS without issues.

 

[gti2slow]

Its semi common, I have a rev D dv and a APR K04 and have similar issues.

 

[eiresgaus]

Its semi common, I have a rev D dv and a APR K04 and have similar issues.

Is it just something to live with? The flutter at high boost isn't much of an issue, it's the hesitation and small flutter in the lower RPM (where with the K03 it would hiss as if air was being released) that I find annoying.

The boost completely drops for a second and then builds back up. It really feels like it shouldn't be normal.

 

[TypeR_126]

Sounds like your'e getting surge, but it shouldn't be bad enough to cause the dip in acceleration you're mentioning unless you're giving it a lot of throttle at very low RPM. The K04 flows a lot more than the K03, so some surge is not uncommon until the VE of the engine catches up.

 

[ROH ECHT]

Too much internal wastegate preload on the actuator rod...needs adjusting so there is less.

 

[gti2slow]

I would avoid touching the wastegate at all costs, it's not something that can be accurately set on the car.

 

[clockwise33]

I would avoid touching the wastegate at all costs, it's not something that can be accurately set on the car.

I have experimented with lots of different settings on my K04 wastegate to arrive at a good medium between limiting boost spike and holding requested boost at high rpm. I'm currently at 2 turns less preload.

As long as you keep careful notes on your adjustments, you can always reset it back to factory if need be. Also a good idea to make adjustments in 1/2 turn increments.

 

[eiresgaus]

Sounds like your'e getting surge, but it shouldn't be bad enough to cause the dip in acceleration you're mentioning unless you're giving it a lot of throttle at very low RPM. The K04 flows a lot more than the K03, so some surge is not uncommon until the VE of the engine catches up.

It's a complete drop in boost and happens at about 1/2 throttle, any less and you can kind of feel it but there's less of a dip I assume because there's less boost.

Perhaps it is the wastegate? As the timing of the dip is the exact same as when I could hear the noise of the intake switch to more of a hiss which I would guess is a release of pressure?

 

[MattCHS]

If you hear it though the intake, it sounds like a diverter valve issue, not waste gate. Even when my waste gate blew wide open, it never dumped all the boost. I don't think it has enough flow to completely bypass the exhaust around.

What revision DV do you have? I had a rev C blow out ( I actually liked the C, it was a little quicker and had a totally different tone) and it was kinda the same. Shit throttle response but still would build 17psi.

Is your valve relocation kit close to the turbo? If its like mine (Revo) you can put it in backwards to where the boost pressure is pushing from the back side of the DV, not from the front of it. It's hard to explain but I had to do a double take on mine when I installed it.

 

[eiresgaus]

If you hear it though the intake, it sounds like a diverter valve issue, not waste gate. Even when my waste gate blew wide open, it never dumped all the boost. I don't think it has enough flow to completely bypass the exhaust around.

What revision DV do you have? I had a rev C blow out ( I actually liked the C, it was a little quicker and had a totally different tone) and it was kinda the same. Shit throttle response but still would build 17psi.

Is your valve relocation kit close to the turbo? If its like mine (Revo) you can put it in backwards to where the boost pressure is pushing from the back side of the DV, not from the front of it. It's hard to explain but I had to do a double take on mine when I installed it.

I might have to try that. I haven't changed the DV since I've had the car (4 years) and so might just do that first to a rev D and see how it goes. If there's no change I'll try your idea of putting it in backwards, it is a relocation kit that keeps it close to the turbo, not the one that brings the DV to the front of the engine