1.6lTD long-runner intake manifold

[greggearhead]

Keep up the good work.  This makes me happy I will likely be mounting my turbo lower.

[fspGTD]

Pic update...

Turbocharger gasket / spacer, fabricated out of 1/8" copper:


Intake manifold adapter piece progress (rough-cutting is almost done)



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Air die grinding tools doing most of the work, from left to right: grinding stones, die grinder (with cartridge roll mounted on long mandrel), large cross-cut carbide burr (for steel), 2 small aluminum cutting carbide burrs, 2 short cartridge roll mandrels (one with cartridge roll mounted), small cross-cut carbide burr for steel, 2 flap wheels.


My recently acquired air compressor, providing the grunt labor for all the cutting and shaping, after being modified with an added 32 watt cooling fan (in rear, at left in pic) and aluminum sheet shrouding (visible in front) to direct needed cooling air to the cylinder head for hours of flat-out metal shaping fun.  :twisted:

[malone]

Jake this is awesome, I love watching your work

[fspGTD]

Dvst8r asked to post up some pics of my oxy-acetylene aluminum welding, so here you guys go...

This is a really big hole that needed to be plugged.  It was where the EGR piping (which is now cut off and ground away) entered into the plenum.  I opened it up until the wall thickness around the hole was uniform and made a "keystone" shaped cross-section so I could make a plug that fit securely without falling through:

Here is the plug fabricated out of 1/4" 6061 (and the tighter the fit-up, the better):


The area pictured above just welded (flux resides also washed off with hot water and soap):


... and now after grinding the beads down flush we can see how good the fusion really is.  What a successful weld will look like here is uniform metal.  This looks pretty good, but there is one area in the upper-right of the weld bead where a telltale thin line of non-shiny oxides shows that the molten metal didn't flow together correctly:


There are a couple little holes (originally brake booster vacuum line and valve cover crankcase vent return lines on the gasser application) that I wanted to plug so I started by fabricating tight fitting plugs and hammering them snugly in:

then, the view after welding:


And after being ground down:

The weld beads on both of these plugs had perfect fusion all the way around on both!  I think the reason they came out so well was I had my flame set very hot when doing them.

But another area I tried welding (an attempt at repairing a previously botched weld) didn't come out quite so well.  I didn't use enough heat so didn't get good fusion.  I might have to try re-welding it... again. :roll:

Previous botched weld ground out ready for repair attempt:

After welding repair attempt - before cleaning off flux and oxide residue:

After cleaning off flux (just soap and water):

And after being ground down flush.  Yikes, this doesn't look much better than it started.  The metal has many areas that didn't get fused together.  This is because I didn't use a hot enough flame.


This has been good practice, so I feel more prepared for taking on the more challenging aluminum welding jobs needed elsewhere on the manifold.

[RabbitGTDguy]

Jake, just to give you an idea of "how" i'm refining my manifold idea this time around with the TDI vs. the plenum style I had before...here is what I'm working on...may help with your project too as far as an inlet piece and "what" i decided to use....

I'm going to be using the G60 manifold. The ports need ported out rather heavily to match the D ports of the TDI, but I believe there is enough material...i'm going to work on marking it tomorrow.
Here is the manifold fresh and clean ready to mark and port



However, the inlet piece is a bit more interesting. The one problem i had before was getting the very "crude" inlet flange I had made for the GTI manifold was getting it to seal well. This time around I thought about my experiences with the Corrado G60, then Lysholm I had and built. I remembered that the throttle body consisted of two parts. the TB itself and a section that bolted to it that was for boost return from the supercharger. With a little modification this is going to work well IMO. I don't have a pic up tonight of what it looked like prior...but you'll get the idea when you see this...
The piece


Here is a shot of the bottom where I cut off and removed the butterfly valve for the boost return. I'll only need to have a cap welded over this hole after I smooth it out and its finished...


Fitted to the manifold....




How is yours coming along?

[fspGTD]

Hey Joe - nice G60 boost tube adapter piece!  What is the inside and outside diameter of that boost tube connection?  It looks very good and I'd be all over finding one just like it to use on my project if my plenum weren't so tight against my valve cover.  But since mine was so tight to the valve cover (I had to hack off a corner of the throttle body flange, including a bolt hole, to get it to fit), I will be doing something necessarily more tricky.  I will weld material inside the opening at one area to build up the sealing surface and also will tap a new bolt hole.  I'm also planning on re-using 2 of the original throttle body bolt holes, for a triangular shaped bolting pattern.  To make the boost tube adapter piece, I'm planning on using an aluminum boost tube piece I got from a Saab which has close to exact the same diameter as my current boost tubes (about 1 7/8" OD).  I will cut the beaded end off and weld it to an aluminum plate and bolt that to the plenum.  I decided that the boost tube will be off center from the old throttle body opening to position it better.  To achieve this, I hacked out some of the throttle plate sealing surface and even some of the plenum wall.  :shock:  (I'll build back up new plenum wall spaced farther away by welding on some aluminum plate.)

I've also cut off the v-band blow off valve flange from my scrap pieces of old 1.6lTD intake manifold plenum, and will be welding that to my new manifold's plenum wall just around the corner from the bolted on boost tube connection.  I test fitted everything in the engine compartment first, which I'm glad I did, because the original blow off valve position I had in mind farther away from the throttle bolting surface would have been in the way of the LDA.  The newly planned place I have for it has comfortable clearance.

I also took a close look at the planned boost tube routing from the intercooler to planned plenum connection, and it is looking great... much shorter than my old boost tube setup.  There is a long section of my old boost tube, probably about a couple feet that I won't use at all with the new intake manifold, and I might not have to modify the boost tube that couples compressor outlet to intercooler inlet at all!

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I did some successful welding last weekend, repairing almost perfectly the previously botched welds.  After being ground down, you can't even tell it was ever welded in the first place...    I am learning how important it is to vary the heat when welding aluminum, and the heat this big manifold needs to get up to welding temperature at first is tremendous... but using essentially all the heat I can muster from my torch setup cuts my pre-heating time and gas usage considerably.  Of course then there is the problem of having to dial the heat down after welding starts, to keep the molten puddle from growing too large.

[RabbitGTDguy]

Jake, the ID on the G60 boost return section of the throttle body is 2.25 in. and the OD on that same inlet side is 2.5in . The portion of the plate that mounts to the manifold itself uses the same port design and gasket that a standard 8v throttle body uses... very nice...should flow very nice Let me know if you want more detail pics or something...there are a few up for sale on the vortex... Just post looking for a "G60 boost return valve off the throttle body"



Joe

[fspGTD]

Plenum work update pics from today...

here is the plenum cut out to reconfigure the throttle inlet plate for the boost tube inlet:

I cut pieces away squarely, so I could weld in tight-fitting pieces of 1/4" plate.

Here is the first piece of plate set in place, all prepped and ready for welding:

The round hole by the way is where I'll be put the blow off valve.

Here is welding progress with the first and second pieces successfully welded:


Now there's a third piece welded on on top of the second to build up the flange area:


Here is how the built-up flange area looks with the boost tube coupling held where I want it to be located.  I know the location seems kind of random just from looking at this picture, but when I get it done and mounted in the engine compartment, you will see why I chose this position.


And here's what the flange looks like without the boost tube coupler:

I've still got to weld in some more plate to build up the flange some more, and then I'll file it flat and make a boost tube coupler piece that will bolt on.  Very much a work in progress...  

[fspGTD]

I did some more fileing and shaping on the plenum.  I made a plate (pictured below), which I'll weld into the plenum opening to partially close it off.  I'll re-cut a new hole in an offset position so the boost tube inlet won't be so tight against the valve cover.


Hopefully all this plenum fabrication work will end up making sense when I'm done. :shock:

[DVST8R]

Makes perfect sence to me. Now as long as it still makes sence to you, your set.  

[fspGTD]

Well, it makes a little more sense now.  The design is definitely evolving a bit as it's being built. :oops: The blow off valve flange is now welded onto the plenum, the the air inlet flange is just about done.

When I first tried welding the BOV flange to the plenum, I tried my usual procedure of just going at the massive aluminum piece with a very large tip with very hot flame setting.  Well, this caused problems with the lightweight blow off valve flange coming up to melting temps much quicker than the relatively massive intake manifold piece which conducted heat away from the weld area.  Despite doing my best to direct the temperature of the flame to the manifold, the heat control was very poor, and I melted away some areas of the BOV flange - some where the v-band clamp touches, and one melt through was so bad even part of the critical o-ring sealing surface fell away!  :shock:  By the time that happened, I knew what I was doing just wasn't working, and so I stopped before the damage became irreversable.  I then came up with a new strategy: I would try pre-heating the manifold to 400 degrees F in an oven, then see if the larger piece would melt easier.  I used a smaller flame and less heat.  The pre-heating method worked so well, I manage to pull off a perfect 360 degree weld that perfectly fused and sealed the inside diameter of the blow valve to the plenum!    The molten puddle was much easier to control.  I'll have to remember to pre-heat more often when welding dissimilar metal thicknesses.  I also successfully built up a weld bead to replace the areas that had fallen away.  I'll have to shape them carefully with a file to restore the original surfaces.

The air inlet flange is coming along nicely.  With a hole saw, I made about a 2" hole in the face of the air inlet flange.  I'll enlarge that to at least the ID of the 2.25" boost tube to allow me to move one step up from 2" boost tube size if I wanted, and the larger hole will also give me better access to inspect and clean out the inside of the plenum.  To accomodate the larger hole size, I am leaning towards using a 4-bolt (trapezoidally shaped) sealing flange instead of a 3-bolt / triangular shape.  The material where I'll need to drill and tap one of the bolts is a little thin walled and I might only get about 1/4" of threaded meat though - worst case scenario is to add more threaded area, I'll need to cut the section away and replace it with a thick aluminum chunk in its place.

I am trying to figure out what to do with the boost tubing.  Here's what the old configuration of the engine bay and boost tubing looks like:


The intercooler outlet diameter is 2.25", and the old configuration of boost tubing has the air go through a crappy nonreinforced rubber 90 degree hose (would really like to get rid of this) before transitioning down to a 2" tubing size.  Even though I found the intercooler and boost tubes weren't highly restrictive after installing them as measured by my boost gauge, I'm thinking a little airflow optimization here might be worth my while.  Not sure yet if I'll stick with 2" OD boost tubing to the intake manifold, or step it up to 2.25" OD.

[935racer]

Looks like a lot of work hopefully it all pays off  When I do intercooler fabbing I make the piece from the compressor to intercooler 1 piece and the piece fromt he intercooler to the intake 1 piece. Always, which sometimes means I fab up some pretty crazy looking snakes but I think it is worth it for optimal flow. Also why not try a cross flow IC? I am in the middle of fabbing the charge piping for a 16vturbo in a rabbit right now and we ordered this great cross flow IC that fits in front of the rad. I'll see if I can get some pics up soon.

[fspGTD]

All an intercooler can hope to do is cool the intake air to nearly ambient temp while giving nearly zero pressure drop.  Based on tests done with my current intercooler (Audi5000) at pressures up to 14.5 psi being tested, there is just too little room for improvement left on the table to warrant any changes.  The intercooler was already 85% efficient at cooling the charge and had less than half a psi pressure drop.

However, I will continue to monitor its performance at the higher boost pressures I plan to run at, as it will get more heat thrown at it it will need to cool, it is likely that it won't keep up quite as well.  I've added good baffling and radiator fan pulling air through it I will let run in grid to keep it cool though :twisted:

I am a little concerned about how much boost pressure the plastic end tanks are OK at, but I am looking into adding some reinforcements.  Just got a lot of other things to do to prepared for 2006 racing season, and time is ticking away.

I'm always interested in seeing other Rabbit intercooler installs, and would be even more interested in hearing about other intercooler test results.

[caddy]

what did you think about this setup?

[Black Smokin' Diesel]

That's from the almighty Zonker right?? This intercooler setup is really cool and functionnal.