Project Potential... variable vane turbo on 1.6l

[fspGTD]

In the middle of fabricating the downpipe:

[MrDave]

Jake,

looks very nice.   With the hours you currently have in this thing, be very glad you're not paying  a shop to build it for you...

And don't forget to install a support bracket for the bottom of the turbo.

-Dave

[fspGTD]

Thanks Dave - I've been meaning to ask where does the flange at the bottom of the turbo bolt to on the TDI motor?  I can't find an obvious place that looks like it should bolt to on the 1.6D motor, and I also can't find anything that looks like a turbo support bracket in ETKA for a 2001 TDI Golf.

[MrDave]

There are numerous bosses on the back of the TDI engine block.

This is the best picture I have, but it still doesn't show the boss that the support bracket bolts to:




The support bracket is simply just a short angle bracket, comes off the turbo, bolts to the block.

-Dave

[lord_verminaard]

Try an 038 145 535 B

It doesnt look like much in the picture (145-55) but the pic of the turbo is pretty much generic so who knows what it actually looks like.  There's also the one for the 1.8t, 06A 145 536 B but I doubt that would fit.  All else fails, get some angle iron and weld er up.  

Brendan
84 Scirocco 8v
00 Camaro L36 M49

[fspGTD]

Thanks for the turbo support bracket info and part numbers, guys.  Looks like it is not that expensive of a part; impex lists either one under $20.  I will have to check out what it looks like on a TDI.

The downpipe is now finished.  I managed to position the flex joint not too far away from the turbine outlet:



Installed:

[malone]

Nice job, I can't wait to see how the car performs!

[TDIMeister]

That's some top-notch fabrication work, Jake!! WOW!  :shock:

[Staley]

Jake,
what diameter pipe did you use for the downpipe?

[fspGTD]

Thanks guys!  

Update: I finished the installation of the under-car shift boot, which was a challenge with the EMPI Rabbit shifter.  Will post the details in the "EMPI Rabbit Shifter Review" thread: http://www.vwdiesel.net/phpBB/viewtopic.php?t=1146

I wanted the boot installed before I did the exhaust in that area, so I could make sure I routed the tubing in a way that didn't interfere with the boot.

Staley: I used a mixture of stainless 304 and 409 grade 2.5" OD tubing for my exhaust fabrication work.  The 2.5" tubing diameter will be maintained until after the under-car shift boot, where I will couple to the old 2.25" exhaust system.  There is an old resonator before the over-the-axle pipe; I could either adapt to that or cut it away and adapt directly to the 2.25" over-the-axle tubing.  I have very little doubt that it will be quiet either way with the 2.25" dynomax super turbo muffler.

[fspGTD]

Here is what I did for the turbo support flange.  I cut some electrical conduit, and pinched and drilled holes in the ends.  I mounted it to a boss on the block that was fairly close to the turbo support, where I installed an 8mm stud and shouldered locking nut.  To fasten to the turbo support flange, I managed to come up with a 10mm bolt and nut / lockwasher that fit pefectly.



I am almost done with the exhaust.  I cut away the old resonator, which was quite heavy and seemed to be pretty plugged with carbon (not sure if it was doing much!)  I just have one weld connection left to complete the exhaust system.  I had to take off the front antiswaybar to remove/install the exhaust piece I am working on.  It spans from the flex joint all the way past the under-car shift boot.  The new gauges are also now all wired in too (gauge lights and everything.)  Should be able to monitor EGTs now.

The Mann Provent arrived.  Looks like a high quality unit, but it is quite large!  :shock:  It's gravitating towards being installed next to the windshield washer fluid reservoir, behind the battery.  There is enough room for it there.  But I'll probably delay installing it until after I drive the car!

I want to take this VNT action out onto the road already!  :twisted:

[fspGTD]

I finished the exhaust and test drove the 1.6 VNT Rabbit today!  I'll post details of the latest exhaust work I did later, so skipping to the test results:  It turns out that the vane controls are not working right on this first iteration of the manual VNT controller.  What happens is that when RPMs and/or load get high, the boost pressure skyrockets, easily pegging my 15psi boost gauge (I tried to keep it from doing that.)  So I suspect the vanes are not opening (or if they are, they are not opening enough!)

But it worked fine on the test bench... so, what I suspect is that the exhaust airflow through the vanes is applying a rotational force on the vanes and preventing them from opening like they did on my test bench (completely open by 15psi: http://www.vwdiesel.net/phpBB/viewtopic.php?t=1306&start=28)  Pretty interesting results.

Luckily there is a lot of room behind the turbocharger, and I modified the can so it can be opened and closed again, so this means I might be able to try different iterations of the VNT controller without a whole lot of fuss.  Maybe I can even unbolt the VNT can from the turbo without removing it from the engine!  

Some good things from the first road test: the exhaust system seems aligned perfectly, no rattling at all.  The new motor mounts are nice and tight and engine idles quite smoothly with minimal vibrations.  All the coolant hoses and the coolant level held, so the new head gasket seems to be working.  No oil leaks anywhere.  Basically, everything besides the VNT controls worked great!

The engine even SOUNDED great with the VNT.  It was pretty unique and interesting sound.  Distinctly different from the low-pitched whine of a 1.6lTD.  You can hear a distinct sound out the muffler that sounds sort of like rushing air combined with a faint high-pitched whistle, but overall it's nice and quiet exhaust noise even without the resonator.

This turbo just spools up SO quick.  It's totally crazy.  If I can harness the VNT by figuring out a way to control it, this is going to really broaden the torque band down into the low RPMs.  I verified that it does put out boost pressure at idle.  I didn't even trust the gauge was working as this seems so amazing to me, so watched the gauge as I turned off the engine.  It dropped downwards, all the way to zero, right after being shut off!  When fully warmed up, it is probably putting out nearly 1/3 of a psi AT IDLE.  Amazing stuff.

The engine also seems like it might start and stop more abruptly, why exactly I don't know but seems different somehow with the VNT.  Either it's because maybe more pre-turbine backpressure... or maybe there is more compression during starting with the VNT assistance!

During the test drive I tried a short freeway section (didn't work very well with overactive VNT... had to keep speeds really slow to keep from overboosting) and anyway the cheap boost tube adapter I clamped on there blew off.  Nothing too traumatic - I've had this happen on my GTD Autocrosser 1.6lTD before I got the boost tubes beaded behind the hose clamps.  I knew what it was, and just put on the hazards and snailed very slowly to the nearest exit and parking lot.  Well when I kept the enigne idling and popped the hood to replace the blown-off boost hose, I was surprised how STRONG the wind coming out of that open boost tube was!  I mean I don't know how fast a 40mph wind is or whatever, but I can just say this was a really strong wind.  Not like what a 1.6lTD would be blowing at idle for sure!  It really seemed amazing.

Now that I've gotten a sense for how quick spooling the VNT is capable of, I wouldn't mind just hardwiring the vanes open now and driving it around like that to get a sense of what the VNT-15 is like with vanes open.  IE: see if I can get it to make any boost at all like that, or not.

I am not really sure yet exactly what I'm going to try next for the vane controller.  I must admit I am a bit concerned after learning that the only other non-TDI production car that came with a VNT turbo, the Dodge Shelby CSX, had also used computers to control the VNT vanes.  Knowing that no other manually-controlled VNT turbo'ed cars have been produced is not confidence inspiring!  :?

Edit:  here is the latest picture update...
fabricated center exhaust tube:

installed:

a little detail you Rabbit folks might like - I increased clearance for the exhaust by extending the bracket that holds the fuel tank mounting strap.  The strap now is held much closer to the fuel tank, allowing more clearance for the exhaust tube which passes underneath.  This worked wonders for aligning the 2.25" techtonics over-the-axle exhaust pipe.

[RedRotors]

Really interesting result Jake.. VNT spool in a blink of an eye and is capable of a 18-19psi substain w/o problem.. In the case that you can't make this thing work mechanically, i probably can make something for you.. Keep us informed! Good work!

Marc/

[jackbombay]

what I suspect is that the exhaust airflow through the vanes is applying a rotational force on the vanes and preventing them from opening like they did on my test bench (completely open by 15psi...

 

  Could you use a softer spring for resistance in th can to end up with fully open vanes on the bench by 6 PSI?

[TDIMeister]

Jake, you can adjust the VNT initial position by twisting the threaded VNT actuator rod.  You can find out more about it by searching TDIClub with the keywords "negative VNT twist" or some variation thereof.

You want the vanes to be more open initially.