GFB V2 VNT controller for MTDI build

[Paul18181818]

I’m assembling a 1Z engine for a 50 degree install on my 89 Vanagon, and I have yet to select a turbo. I’m planning on using a Lr 300tdi pump and I’d like to use a B5.5 passat VNT turbo.

I came across the GFB V2 part when searching for methods to actuate the turbo. It marketed like a stand-alone controller, but the reviews online seem to imply it’s used to tweak the factory ECU’s vane control system.

Does anyone have any experience with the GFB D-Boost V2 controlling a VNT turbo in this application? Will the performance be significantly limited compared to an electronically controlled VNT?

Also, has anyone tried bolting up a VNT17 to an AAZ exhaust manifold? I know that this manifold is preferred for the better drain angle vs the integrated VNT manifold.

Thanks in advanced, this forum has been an immensely useful resource in planning this build and I appreciate the effort people put in!

[MarkWard]

A few years ago we had a TDI ALH with an unmarked mechanical injection pump. It had a home made looking standalone VNT controller. The combo was junk drivability. I have a factory ECU controlling my N75 and VNT. It’s so smooth you can not detect it working.

I don’t recall the brand of standalone, but it did not play well with the N75 or VNT in my opinion. There can only be a couple out there and likely this is the same kit. It’s a clever idea, but didn’t seem ready for prime time.

Others will chime in. Bump. Ask member Waldo.
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[valvecovergasket]

Just to restate the obvious here - you're attempting to build an mTDI because as I've read here they're sooo super simple!
...but realizing that the "m" part indeed has limits you want to add some random VNT control?

Why not just.... build it to use an ALH ECU? and have actual boost and VNT control and the numerous other benefits of having an ECU?

This strikes me a bit like trying to build a digital abacus.
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MegaSquirt resource - SpitfireEFI.com

gone, but not forgotten: '83 tdi westy - swap thread

[MarkWard]

I totally understand the simplicity of a converted to manual injection pump on a TDI. 15 years ago, I was skeptical of a computer controlled injection pump. Almost 80,000 miles later, I had 2 problems. One is the pump head O ring would weep sitting in cold weather. Easily replaced with pump installed. The other took some time to figure out. It ended up being an intermittent fuel cut switch.

I accidentally bricked my stock ECU swapping a spare in and out. Long story. I sent the ECU to Tunezilla to have the chip socketed and a couple minor tweaks. EGR and Hard start hot crank specifically. I have Sprint Bozio 520 injectors. Everything else is stock from VW. It’s almost scary the power. I actually back pedal in first and second.

We use the van for traveling. I carry a spare ECU, but knowing everything else is available and bolt on is worth peace of mind. All I need is an address for shipping. Good luck getting it sorted. I always wondered how boost was handled when deleting the factory ECU. Post up your results.
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[Paul18181818]

Thanks for the feedback. I'll likely stick with a wastegate turbo with MTDI pump for the short term to get the van running unless anyone else chimes in with a better solution.

Fair point valvecovergasket, the ETDI setup for VNT could be a simpler way to go if I decide to upgrade in the future. The GFB part seemed like an easy solution to the VNT control problem, but I have my doubts about the part given what little I could find about it online.

[MarkWard]

I went ahead and searched the component name. Would have been nice if you added a link. This is definitely not what came across the shop. It looks strictly mechanical. No N75 required.

All I know is my VNT works. It gets full vacuum from the vacuum pump through the N75 valve. When the computer senses over boost, the N75 likely bleeds vacuum off allowing the VNT to open and bypass boost. In operation I don’t know if it’s constantly adjusting which I doubt because the vanes will seize in full position. So, if you did not overboost, you could likely just run vacuum direct to the diaphragm and watch a boost gauge and modulate with your foot.

They don’t really get into the science of their part, but it seems to have enough ports to accomplish what the computer and N75 are able to do.

Looks relatively inexpensive and you could run it up to the steering column for fine tuning. I’d say pull the trigger and let us know how it works for you. As I said, our van is scary fast. Wouldn’t want anymore torque or hp.
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