Diverter Valve Upgrade - GFB DV+ T9381

[nermal]

I replaced the OEM diverter valve today with a GFB DV+ T9381 - it's an all in one unit with solenoid that completely replaces the factory part.



The GFB DV+ is a more precisely engineered and shorter than the OEM DV (makes installation easier than OEM removal). The OEM DV piston is plastic and had a bit of play in it... Red piston clip on the DV+ has to be carefully removed prior to oiling and installation.



I think it was a worthwhile upgrade. There seems to be an improvement in throttle response - seems like a bit more torque is more readily available, feels like it builds/holds boost more readily and there are less turbo noises (the sounds have also changed somewhat).

The installation would have been a ~15 min job IF I had the right tools, but given that the larger/upgraded turbo elbow partially blocked the lower bolt, all my tool options wouldn't reach the lower bolt properly (top 2 were easy).. so, it actually took me over an hour (closer to 2 hours).



Would have been handy to have a universal joint extender for my socket, or maybe a perfectly-sized allen key (which I tried to make by hack-sawing a longer one)... so I made a franken-socket using a fence-screw drill driver/bit, a 1/4" socket and some electrical tape.. even though I had a telescopic magnet to fish out any dropped tools/screws, I still didn't want to try it out if possible (hence the electrical tape).



Anyhow, the steps were relatively simple:
- remove the inlet hose
- remove the OEM DV plug (has a tab to release first)
- undo the bolts (swear at that bottom bolt a few times - seems to help, make dodgy custom tools)
- remove the factory DV, add some oil (from the dipstick) to the GFB DV+ piston
- position and bolt in the DV+ in place
- connect the DV+ using the adapter/extension plug
- replace inlet hose
- test drive
- smile

[nermal]

I ended up removing the DV+ last night. I'd noticed some rough gear changes and a light shuddering at times when backing off the accelerator. Thinking the DV+ may be sticking, I decided to remove it and see if it needed re-lubricating or something.

Upon removing it, it looks like the oil had dissipated and the piston had started to wear/scratch - likely leading to the 'sticky' behaviour. There was also wear on the inside of the piston, from the rough/ground spring surface. I also noticed some small bits of metal debris on the mounting plate (where some oil residue had also accumulated) - but this is likely from some slight wear I noticed between the bolts and the mounting plate.



When installing, I had followed the instructions and applied a generous coat of oil from the dipstick to the (entire) brass piston part. There weren't any noticeable scratches during installation either.

It's quite disappointing as the DV+ was a great upgrade when first installed. I really enjoyed the (incremental) improvement in throttle response and would have preferred to keep it, if it had continued to perform. I didn't think to check the turbo DV mount/manifold for corresponding wear/damage, but I'm thinking (hoping) the scratches are most likely from the piston sliding inside the DV+ and not my turbo manifold.

It seems the DV+ has some real lubrication/wear issues to solve - perhaps it needs a dry lubricant (eg. graphite, teflon spray) or a permanent non-stick coating (eg. ceramic, teflon) that isn't affected by heat and doesn't dissipate over time.. or perhaps even some sort of wet lubricant reservoir (maybe grease topped up via a nipple, if not too sticky?)...

[genebaby]

That's sad to hear. I was thinking of one of those down the line. I'll need to hear some good reports they have fixed this before I think about getting one now.

[nermal]

Yeah, I really liked it when it was first installed and operating smoothly...

I've been wondering if I can get the piston re-polished and coated with ?some? dry, heat-proof, anti-friction material. Would love to put it back in if I could be confident it'd continue operating as expected.

Though, I also don't want my engine to be the guinea pig or to be pulling diverter valve in and out multiple times. Not sure if those bolts are meant to be single-use too...

[REK]

Doesn't this part have a lifetime warranty?

[nermal]

Sort of - it seems to be Australian consumer law marketed as lifetime warranty: Warranty - GFB Performance turbo tuning products

I want to see if there's a solution to the oil starvation/scratching before I install it back onto my (expensive) engine. The DV is angled and gets hot, so any lubricant applied will eventually drain into turbo manifold. I just didn't expect it to happen so quickly.

Hoping there may be a suitable anti-friction dry coating solution or something...

Edit: these look interesting (up to 300/315°C).. but again, I prefer not to be the guinea pig.
MOLYKOTE(R) D-7409 Anti-Friction Coating
MOLYKOTE(R) 3400A Anti-Friction Coating LF

[petemac110]

I'd strongly suggest getting in touch with Brett @ GFB via the tech support link below - if they product isn't functioning as intended, let them know and ask them to solve it! Without a feedback loop such as this, they'd be none the wiser.

Tech Support - GFB Performance turbo tuning products

[nermal]

Yeah, you're right.. I should see if they have a solution.

[genebaby]

Would be good to hear what they say.

[nermal]

GFB got back to me and it seems that the scratches and wear are normal after the initial bedding in.

Not sure what was causing the hard shift/light shuddering after it'd been in a few weeks, but one of my engine mounts is starting to sag a little, so that could have been be amplifying things. Symptoms weren't that severe and calmed down after putting the OEM diverter valve back in.

Just to be sure, GFB want to swap it out under warranty and check the part over/investigate further.

[genebaby]

Good to see they got back to you. Wondering what they will say when they inspect it.

[nermal]

Received the replacement unit and sent the old one back.

I've been thinking about how the newer VW oil grades are thinner and if this may have affected the initial lubrication and wear in..

Also, the brass metal filings from inside the piston (created from the rough spring grinding against it) would have to go somewhere - this could be a possible cause of the scratching on the outside of the piston.