ThunderDent

After about a month of driving with the much increased boost pressure from the APR K04 upgrade (and next to nil in the turbo whining sound), I started noticing a really high pitched noise that was still kind of quiet at the time. It really only happened between about 2200-2500 rpms and mostly when I was in a higher gear and pushing down on the throttle just a little bit.

I attributed this to the possibility of the turbo breaking itself in and didn't think anything too much of it at the time.

Well, it has gotten a lot louder lately (it's been a few months now that I've had the K04 on). My dad was riding with me the other day and he asked what was wrong. I told him I thought it was the turbo breaking in, but it was getting louder and I didn't think it was sounding right. He said, that's definetly not the turbo.

I don't yet have a boost pressure gauge (it's coming soon hopefully), but I can tell that I am loosing some boost pressure. Not all, but some.

It sounds like a cross between a squeaky belt in an old car and a locust (cicada) chirping. It is loud, but soft sounding and only happens when the throttle is pushed just a little bit in a high gear. It feels as if I'm loosing the full boost pressure I used to have.

The engine runs fine, the car throws no codes, everything is good. No seizeing of the turbo or anything like that.

With all the early data out there suggesting Audi/VW diverter valves have a horrible history of failing, especially after ECU upgrades and bigger turbos/more boost, I really think this is what is failing.

It is probably some boost pressure escaping the diaphragm that is not keeping it sealed when it needs to be.

So my question is, for those who have crossed this bridge already... What is the best DV to get. Electronic or Vacuum? Piston or Diaphragm?

There are several out there. The APR R1 looks great and touts that the diaphragm is waaaaay better than a piston, as the piston ones have to be taken off yearly and greased. But they don't make one that I've seen for the 2.0T. Pretty sure the OEM is electronic, but not sure. I know it's diaphragm.

Here is what I've found. Suggestions are welcomed! Thanks.

This one is electronic/piston and is priced very well.
http://www.ecstuning.com/Audi-Q5-Qua...alve/ES263879/

This one is found on Porche's and is rated to 750+ hp. It is Vacuum/Diaphragm, and requires a boost tap to use it.
http://www.awe-tuning.com/products/a...awe-b8-dv.html

This one is electronic/piston or diaphragm???
http://www.drivtechonline.com/Forge_...m-fmfsitvr.htm

Not sure this even fits... because it doesn't say.
http://www.lltek.com/DBOV_turbo_divertor_blowoff.htm

AudiQ5sleeper

Get the first link you posted. i need one as well for stock boost.if you end up getting a BOV which is similar to the diverter valve. a friend of mine upgraded the turbo. He needed a new diverter valve. thats alot to do for boosting and it gets very expensive lol

ThunderDent

Is the ECS tuning one basically the same DV that all the upgraded Audi/VWs have? It seems like it reads that way.

I've heard really good things about the Forge valves.

Not sure which I'm going to do.

AudiQ5sleeper

get the DV from ECS tuning, the stock DV will divert the boost back into the intake instead of the atmosphere. but if your willing to spend the money on the BOV, it will sound sick. But then you will need to purchase the boost tap.

http://www.ecstuning.com/Audi-Q5-Qua...ake/ES1832412/

ThunderDent

Sick as in awesome or sick as in cough cough?

If I add the Forge BOV, and it is metal, would it not work better with the Forge DV?

I dont know really what to look for. I need to get it checked out.

I took some vid this morning so others can hear what I'm talking about. I'll try to get i up soon. It may very well just be the turbo, but it doesn't do it throughout the range, so idk.

Edit: Vid is no good. Too much background squeal and I can't hear the actual problem on it.

AudiQ5sleeper

sick as in awesome. Forge BOV would work the best if you got money. Forge DV will work but you wont get the BOV sound. ill ask my friend about it.

place your camera on a tripod and leave it outside. should give you a better chance to record the sound.

ThunderDent

The more I watch vids of cars with the BOV's, the more I'm not a fan of that sound. So maybe the DV only would be my choice if that is actually what's wrong. Those videos on the ECS tuning site are great for learning what is out there and what they do. Thanks for that link.

My favorite sounds in a car are engine & exhaust, and that's about it. Well, save for really good stereo of course.

Here is a second vid I made on the way home. It is a bit better.

Hell, this may just be the turbo, but if it is, I don't know why it doesn't do it throughout the range of driving/gears/boost. I can drive in lower gears and get boost pushing me back in my seat and get on it really quick with just great sounding engine noise in the cabin. I know the turbo is spooling, but there is no noise.

When I'm in higher gears (6, 7, 8) like on the interstate and the car is coasting, and I lightly get on the accelerator, just lightly, then the chirping comes out. If I get on it harder in the pedal, then it goes away. Again, I know the turbo is spooling throughout that range, so if it was the turbo's impeller causing the noise, it would do it more than just on the light touch of the accelerator.

ThunderDent

After watching another vid online about BOVs they said that the cause of chirping is from back pressure on the turbo.

I wonder if maybe the problem is the DV piston is getting stuck when the boost is low, and as it increases significantly when the throttle is pressed in farther that it enough to unstick the piston.

ThunderDent

If I can figure out for sure it's the DV, then I'm basically down to one of these 2 kits.

Forge DV (Diaphragm/Metal/Pressure)
http://www.ecstuning.com/Volkswagen-...lve/ES1832057/

Stock Replacement (Piston Valve/Plastic/Electronic)
http://www.ecstuning.com/Audi-Q5-Qua...alve/ES263879/

I'm leaning a bit more toward the Forge kit, plus since the kit comes with the boost tap already with 3 nipples on it, when I (hopefully) get my boost gauge, all I will need to do is run a line for the gauge. Also the Forge DV comes with the yellow spring that is made for running higher boost.

I read another article a minute ago stating that running a BOV on a closed system (MAF system) is not good. It will cause the engine to run rich as the MAF does not know it lost that extra boost. So I will be going just straight DV.


Anyone have any thoughts on the sound from the video? I couldn't hurt to change out the DV I suppose and see if that helps.

AudiQ5sleeper

def need a BOV and a boost gauge