New Rev G DV failed within 50 miles?

[breeze]

I replaced a failed Rev C with a new Rev G from the dealer and my Stage 1 boost jumped back up to around 20 PSI.

After no more than a few hours driving, peak boost has dropped down to 10 PSI.

I looked at the boost hoses and couldn’t see anything obvious but have ordered the two o-rings for the intercooler boost pipe, which was leaking a little oil. To be fair, the pipe has been leaking for a while. It was still fitted when I removed it, albeit a little loose.

My research points to a failed DV. Is that possible so quickly? The fact that it gets to 10 PSI makes me think it is a part failing under boost (like the DV diaphragm) rather than an obvious hole.

As you all know, a DV swap on a K03 car is’t fun…

[Clarkj93]

Mine seemed to go within about 1000 miles, looked fine but kept letting go off boost at peak torque randomly, changing it to a new one solved this. I heard that the spring in the DV could play a part in it, as I guess if its not holding it tightly closed enough it could let boost seep past. Its definitely worth seeing if changing the o rings for that pipe fixes it first though.

If you do need to change it though I've changed my DV enough times over the last 3 months that I've got it sussed, if you get your head in the wheel arch enough until you are looking at the DV and your facing the front of the car you can see the trickiest to find bolt clearly ( the top one) and you can slide a small quarter inch ratchet and hex bit in there and get access to each bolt without having to constantly move around and using various wobble joints and extensions.

[mjmallia]

I relocated my K03 DV to the K04 location for ease of access....works well and is a cooler working environment for it.

[breeze]

Mine seemed to go within about 1000 miles, looked fine but kept letting go off boost at peak torque randomly, changing it to a new one solved this. I heard that the spring in the DV could play a part in it, as I guess if its not holding it tightly closed enough it could let boost seep past. Its definitely worth seeing if changing the o rings for that pipe fixes it first though.

If you do need to change it though I've changed my DV enough times over the last 3 months that I've got it sussed, if you get your head in the wheel arch enough until you are looking at the DV and your facing the front of the car you can see the trickiest to find bolt clearly ( the top one) and you can slide a small quarter inch ratchet and hex bit in there and get access to each bolt without having to constantly move around and using various wobble joints and extensions.

Which version did you have an or which version did you move to? Also, we’re you mapped?

I was hoping that there would be a way from under the car. Last time was wheel off and liner off, doing it on ramps (the kind used by a home mechanic) would be much easier I think.

[breeze]

I relocated my K03 DV to the K04 location for ease of access....works well and is a cooler working environment for it.

That is interesting. Can you say a bit more? What did you buy - a kit or just the parts?

[pudding]

I doubt a genuine one has failed after 50 miles unless it its defective. Not impossible, but pretty unusual.

I'd say it's the boost pipe O rings.  Weeping oil is the clue there as it's being pushed past the seal along with the boost pressure. Chances are a new O ring won't fix it for long as the engine movement down there causes the pipe to ovalise. No amount a new O rings will seal it up again.  A new pipe is the only fix, but try a ring first and see.

Relocating the DV is a good idea and easy, although not particularly cheap if sourcing the parts new.

[breeze]

I doubt a genuine one has failed after 50 miles unless it its defective. Not impossible, but pretty unusual.

I'd say it's the boost pipe O rings.  Weeping oil is the clue there as it's being pushed past the seal along with the boost pressure. Chances are a new O ring won't fix it for long as the engine movement down there causes the pipe to ovalise. No amount a new O rings will seal it up again.  A new pipe is the only fix, but try a ring first and see.

Relocating the DV is a good idea and easy, although not particularly cheap if sourcing the parts new.

Could the pipe seals lose 10 PSI? I lifted up the car, hoping that the pipe would be hanging off but wasn’t.

I have just replaced all of my mounts (engine, gearbox and dogbone). Subframe unchanged but I did fit an insert - the engine is much more solidly located now.

[pudding]

If that pipe falls off, the car literally won't run.  It happened to me when I didn't fit the bayonet clip quite securely enough.  It blew off at literally 2-3psi, so yep, it's very possible a worn seal can allow 10psi to escape, but it's the short term spikes that bleed off easily. It still has enough sealing integrity to hold a certain amount of constant boost.

It may not be the O ring, but a fiver and 5 mins work, it's worth a shot!

Good job on the mounts. Previous owners of mine had already done the damage so I had to fit a new pipe and it's been bone dry ever since.

[LC5F]

I can see the benefits of of access and reduced heat, but if the K04 diverter location was that good, why would APR go against the flow and machine their K04 turbo's for the K03 location?

There is a seal in the turbo outlet/silencer that can blow out too -very shallow groove, a complete PITA to fit!

[rich83]

I can see the benefits of of access and reduced heat, but if the K04 diverter location was that good, why would APR go against the flow and machine their K04 turbo's for the K03 location?

There is a seal in the turbo outlet/silencer that can blow out too -very shallow groove, a complete PITA to fit!

Cost.

[mjmallia]

I relocated my K03 DV to the K04 location for ease of access....works well and is a cooler working environment for it.

That is interesting. Can you say a bit more? What did you buy - a kit or just the parts?

It cost me about £50 in parts from an S3 that was being broken.....you can use a harness extension, but I unpicked the original from the loom and relocated without issue......just time and patience needed.

I had to also get the alloy bung that blocks off the old DV hole in the turbo.

Had it all fitted about three years now without issue, and it definitely is a lot easier to check now

[pudding]

I can see the benefits of of access and reduced heat, but if the K04 diverter location was that good, why would APR go against the flow and machine their K04 turbo's for the K03 location?

There is a seal in the turbo outlet/silencer that can blow out too -very shallow groove, a complete PITA to fit!

Cost.

This.

CNC'ing is cheap in America as a lot of workshops/tuners have access to one, so it's probably cheaper for APR to run an end mill through their K04 housings than it is to source all the K04 specific DV parts. 

As for the K04's DV location being better or worse than K03's, it was a move VW were forced to make because, for whatever reason, BorgWarner chose not to machine out the compressor housing for a DV on the K04-064 turbo.  I can't think of a single other reason why they would remote mount it.  It certainly wasn't for performance reasons, and VW don't give a rat's about end user maintenance - that was just a positive side effect of fitting it there!

I can imagine VW doing the sums and figuring out it's cheaper to cobble together the remote DV parts than send all the 1000s of K04-064s back to BW for re-machining.

[LC5F]

To me, that's not making sense - considering how many VAG variants with 2.0 TFSI's are out there - the K03 to K04 ratio has to be something like 3 or 4 to 1
If it was such a financial burden, why would they not standardise the cheaper K04 diverter location on the K03? or just use the more expensive on-turbo location for the K04?

Seem to recall reading this mod gave a quicker on/off throttle response - the response improved by the charge air having not to fill / travel along the long pipe doing the "reach around" the engine.

[pudding]

Because the K03 cars came first.  Makes sense to me. If the turbo supplier changes the CHRA design after production has already started, what else can they do?

I don't see how all of the K04 specific DV parts are cheaper than bolting a DV into the CHRA.

[Hypertuned]

The K04 was only standard equipment on later models, think Audi S3, Golf R which inherently were the most expensive models (using a 2.0 FSI / TFSI engine)  in their respective ranges. Having the DV next to the throttle would definitely cost more and there are more parts than just having the DV connected to the turbo.

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