Post by: breeze on January 17, 2022, 08:18:44 am
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…
Post by: Clarkj93 on January 17, 2022, 08:53:48 am
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.
Post by: mjmallia on January 17, 2022, 09:20:14 am
Post by: breeze on January 17, 2022, 09:39:33 am
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.
Post by: breeze on January 17, 2022, 09:40:30 am
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?
Post by: pudding on January 17, 2022, 10:43:34 am
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.
Post by: breeze on January 17, 2022, 11:02:49 am
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.
Post by: pudding on January 17, 2022, 11:34:05 am
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.
Post by: LC5F on January 17, 2022, 05:17:22 pm
There is a seal in the turbo outlet/silencer that can blow out too -very shallow groove, a complete PITA to fit!
Post by: rich83 on January 17, 2022, 09:13:23 pm
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.
Post by: mjmallia on January 18, 2022, 07:38:54 am
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
(https://i.postimg.cc/Rh0KdsnM/Screenshot-2022-01-18-073714.png) (https://postimages.org/)
Post by: pudding on January 18, 2022, 11:29:19 am
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.
Post by: LC5F on January 18, 2022, 05:43:11 pm
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.
Post by: pudding on January 19, 2022, 10:11:20 am
I don't see how all of the K04 specific DV parts are cheaper than bolting a DV into the CHRA.
Post by: Hypertuned on January 19, 2022, 10:57:17 am
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Post by: pudding on January 19, 2022, 12:06:20 pm
The DV was moved back onto the turbo again for the EA888 engines, both on the BogWiener and IHI turbos, so it's clearly VAGs preferred dumping method.
Post by: Hypertuned on January 19, 2022, 12:12:29 pm
Probably why the K04s were more expensive - to recoup the tooling costs to make the DV parts :grin:Was that on the lower end models? I know the MK5 Edition 30, MK6 Golf R & S3 all had their DV moved to near the throttle.
The DV was moved back onto the turbo again for the EA888 engines, both on the BogWiener and IHI turbos, so it's clearly VAGs preferred dumping method.
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Post by: pudding on January 19, 2022, 12:23:59 pm
The K04 EA113 was a bit of a mongrel engine, both in terms of it's long block and it's ancillaries.
Post by: Hypertuned on January 19, 2022, 12:27:39 pm
Every car except the 6R, S3, ED35, TT-S, Scirocco R and maybe the K1 Cupra R. They all basically had a derivative of the EA113 CDL engine....BYD, CDL, CDLA, et al. All E888 engines have the DV on the turbo, even the high power ones.
The K04 EA113 was a bit of a mongrel engine, both in terms of it's long block and it's ancillaries.
Mongel..haha! But a good engine with a lot more character than the EA888.
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Post by: breeze on January 19, 2022, 01:20:31 pm
No change at all.
DV looks to still be fitted properly, next job is to remove and inspect.
Question: Should I be considering a revision D valve? Not keen on swapping as they break (if I find that the new G is split). Aware of the pros and cons and that the D valves can leak from the factory. I should say that VW did try and sell me the D and did say that it was recommended for the car.
Post by: Hypertuned on January 19, 2022, 01:26:37 pm
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Post by: breeze on January 19, 2022, 01:50:47 pm
I still need to confirm that it is the DV although that is looking most likely. I feel like I’ve read every single forum post involving GTI and ‘boost leak’ and it does point towards the DV or something big like a hole in the intercooler when the drop is as significant as it is.
Going back over the timeline, it looks like I had about an hour at the high boost before something failed. Expensive. :grin:
Post by: pudding on January 19, 2022, 02:31:02 pm
What are the other O rings like? Oil patches around the two intercooler connections? Assuming you still have the standard GTI one fitted of course.
Rev D works fine. The people saying they 'leak from the factory' are usually tuners running Stage 2+ boost levels. It's a plastic piston at the end of the day and has it's limitations. I've used it on Stage 1 tunes without any problems. Boost holds just fine.
I don't like the GFB either. I'm on my 3rd. They do work well but they need regular-ish maintenance. The fact the throttle response off boost is so much better with the GFB is the only reason I persevere with them.
Post by: breeze on January 19, 2022, 03:59:25 pm
There is a chance that what is causing the problem is electrical. I disconnected the battery in order to do the engine mounts, so I am thinking that could have reset something.
No fault codes prior to replacing the C or after fitting the G.
I had a good look around the turbo outlet pipe and it looked fine. Nothing obvious.
Stumped. I think the next port of call is probably something along the lines of a physical boost leak test. Possibly N75 or wastegate actuator.
I am very tempted to buy a cheap piston style DV just to completely rule it out.
Post by: pudding on January 19, 2022, 04:22:55 pm
A sharp drop off in boost along with a bigger than usual N75 duty usually means wastegate trouble.
Probably also worth logging the fuel pressure (LPFP) and actual & requested rail pressures (HPFP) just to make sure fuel starvation isn't causing a boost cut.
Post by: breeze on January 19, 2022, 06:21:01 pm
In the meantime, is there any kind of ‘soft limp mode’ that the car will go into if there are issues? Something that is reset when the battery is disconnected?
I’ve now pulled apart both the C and G DVs and the pistons and rubber seals both look fine. That doesn’t mean that they are fine, but does reduce the chance of issues. I think the swap of the DVs and the battery disconnect is what allowed me to hit full boost, but that is no longer available, hence the ‘soft limp mode’ thinking. Car still revs to the redline.
Post by: pudding on January 20, 2022, 09:28:30 am
There certainly is. Mine is currently flopping into and out of limp mode frequently these days. Some days it's a tarmac shredder, and other days it struggles to keep up with an Hyundai i20. As usual, zero fault codes. Just the ECU being all grumpy cat on me.
When you pull the battery, the adaptations and learned values are wiped from the ECU memory, so you get your peak performance back again. Then over some miles (it can take up to 250 miles to relearn) it gradually pulls the fun back. It's why most tuned GTIs feel epic after a remap, and pulls some mega hp/tq numbers on the first few cold dyno runs, and then a month later......meh.
Obviously if the car is a daily, this behaviour is far more noticeable than a weekend toy.
Anyway.....the only 'hard' limp modes I'm aware of are from throttle and crank sensor failures. The latter won't allow more than 3000rpm and the former won't allow any more than a 10mph crawl. Everything else (inc the cam and MAF sensors), the car drives relatively normally - hence why minor problems are so hard to track down. The ECU is too good at band aiding problems to get people home.
Keep us posted!
Post by: breeze on January 22, 2022, 03:03:58 pm
Post by: breeze on January 22, 2022, 10:56:38 pm
Long story short, the app (Car Scanner) that I was using was showing corrected peak boost pressures. In other words it was correctly deducting atmospheric. I thought it wasn’t, so was subtracting 14.5 PSI (ish).
The reason why I thought it wasn’t deducting atmospheric:
- With a brand new Rev G fitted, it showed ~34 PSI peak (and was briefly crazy fast). I read this as 20 PSI.
- After the first drive it started showing ~24 PSI peak (and was much slower). I read this as 10 PSI.
What I think happened is that the boost spiked massively after fitting the new Rev G diverter valve. This was a one-off. Maybe because the battery had been disconnected and all of the adaptations had been lost. That was enough to register on the app. It settled down to a much more normal level for a Stage 1 car after a little while.
I had VCDS delivered yesterday. With logging it was boosting to 20 PSI, with specified and actual matching very closely. In other words, there are (now) no issues at all.
Lessons learned:
- My old Rev C was probably fine.
- You may get a one-off spike with a new diverter valve/battery reset. If you do, it will be fun.
- Car Scanner reports corrected values. Not with perfect accuracy, but for £5 or so quite useful. Probably good enough to tell you if you have a significant boost leak (and whether you need to replace your DV).
- VCDS not offering a mobile app for £225 is ridiculous (sorry, it’s 2022… a laptop on the passenger seat makes no sense). And no, a WiFi web interface for £430 does not count…
Hopefully this is useful to someone. Got there in the end.
Thanks for all the help. :happy2:
Post by: pudding on January 24, 2022, 09:11:03 am
Yep, the wheels of progress turn very slowly at Ross-Tech. I have VCDS 'mobile', but it's basically just a sh1tty little XML thing that runs in a web browser. It can do 'Gauges' but only 4 at once from memory, and setting that up is buggy as hell. And of course, running that on a phone means you have to switch off auto screen lock before using it, or setup and automation.....but iOS doesn't seem to have an automation to disable screen screen lock on a per app basis.
So yeah, VCDS mobile is completely shat really so I use the laptop. Ross-Tech have a forum and if you ever mention how terrible it is, they just churn out the same indifference. "Oh it's a beta and not supported". Yeah, it's been in beta for years.
Until a rival can figure out to read and translate the VAG specific PIDs like they have, we are stuck with it.