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Pig: '79 242 16vT

Figured that may be the case...been avoiding thinking about it as Currently the primary reason to keep boost down is engine management. May not be an issue soon enough. At any rate, if ai find downtime and an excuse I may just do that.
 
Found the sweet spot some more. Cranked down the MBC a little more and the turbo now feels nice and responsive. Car as a whole seems much less happy when the ambient temperature climbs past 85 degrees and it's sitting in traffic a whole bunch, which is fair enough.

Now I'm turning my attention to the PCV system. I have found that my Greddy catch can is not doing all that great of a job at separating oil and air and is just acting as a canister of sorts that accumulates a bunch of milkshake ( it worked much better with the valve cover port but that's not really realistic anymore. Currently I have it venting to atmosphere which has several advantages in terms of keeping the engine from detonating but I'm polluting much more as a result. The challenge with this early style block is that I only have a single 1" nipple coming out of where the oil separator box would rest in a later model block.

Toby Edelman suggests running an exhaust venturi port to have my crank case run as a negative pressure system. I like that idea, just don't know how effective it is.

What say you, TB? I want to convert to a negative crankcase ventilation system. How can I go about it?
 
Ordering a pro-vent and adding a nipple to the valve cover.

Parents are out of town for a month so I'm making use of the offending A4 as my runabout while the 242 squats in their garage on stands, leaking oil.

Taking the opportunity to do some work. Putting it here to refer to later
-passenger side poly engine mount with oil shield
-extension hose and adapter for oil pressure sender plus extra bit of wiring
-ported wastegate hole ~1mm and deshrouded a whole bunch (now that Inlook at it, I'm not surprised that creep was an issue. Looks way better now)
-tightening up rear suspension. There is something clunky out back
-240T oil cooler and Summit Racing filter relocation kit with a gigantic Royal Purple filter. Cooler itself does not fit the stock location so it will probably end up residing under the radiator support
-FRONT MUDFLAPS ARE GOING IN!!!
-fix horn wire
 
harribert said:
-ported wastegate hole ~1mm and deshrouded a whole bunch (now that Inlook at it, I'm not surprised that creep was an issue. Looks way better now)
Click to expand...

Good deal. Hope that works out for you. Keep in mind: the boost pressure you want to run with a particular turbo setup is inversely proportional to the wastegate flow capacity needed. Lower boost --> larger wastegate, since you are bypassing more flow around the turbine to reduce turbo speed. Might seem a bit counterintuitive at first, and easy to forget that particular relationship when you're playing with tuning.
 
For sure. I focused more on smoothing the path for the exhaust to flow into the wastegate. Before 1/3 was covered, forcing a lot of the gases to do a couple 90 degree turns. Should be good for moderate flow.

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On the other hand I found some light foreign object damage on the leading edge of some of the leading edges of the compressor wheel vanes. No idea as to how they may have gotten there...unsure as to whether I should put a new compressor wheel in there or not...

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What say you, o His Duderness? Is it safe to run or do I keep the thing off the road for another week while I get a new wheel installed?
 
Wheel damage looks pretty minor. You could clean it up with a sharpening stone or emery cloth or other very fine abrasive. I'd leave it for now, but make absolutely sure you determine the cause. If your air filter is dirty or coming apart, or there's some junk in the intake tube, you need to rectify that before it happens again.

Where would you get a replacement compressor wheel, and who would VSR balance the CHRA?
 
Duder said:
Wheel damage looks pretty minor. You could clean it up with a sharpening stone or emery cloth or other very fine abrasive. I'd leave it for now, but make absolutely sure you determine the cause. If your air filter is dirty or coming apart, or there's some junk in the intake tube, you need to rectify that before it happens again.

Where would you get a replacement compressor wheel, and who would VSR balance the CHRA?
Click to expand...

Replacement wheel from ATP and the rebalance would be done at Diesel Fuel Injection Service, around the corner from ex-RSI. I'll leave it until I get a replacement DD/a need for a rebuild becomes apparent, whichever comes first.

I'll just clean it up and run it.

I did see that there were one or two tiny chips left over from when the intake tube was put together. I'll make damn sure that it's squeaky clean (Thought it was already, but I digress).
 
Remember that your compressor is a slightly smaller trim than the production GTX2860R. If you get a replacement wheel you'll either need to down-trim it, or (better option) get a standard compressor housing to match.
 
Duder said:
Remember that your compressor is a slightly smaller trim than the production GTX2860R. If you get a replacement wheel you'll either need to down-trim it, or (better option) get a standard compressor housing to match.
Click to expand...

In that case I could also get a 63 or 71 wheel and housing, yes?
 
Not really. The wheel recess is machined into the cast iron center housing based on exducer diameter. It's an integrated backplate, with that thin aluminum ring to adapt it to the compressor housing.

Going to a different sized exducer will require a new center housing; not really an option.
 
If you had access to the parts bin for GT ball bearing center sections it would be no problem to switch center housings and compressor wheels, but at that point you're rebuilding the turbo. No rebuild kit is sold for these so it's not a viable option.

I'm sure you'd be perfectly happy with the standard 58-trim GTX2860R compressor stage if you need to replace your wheel. That's an IF.
 
I'm perfectly happy with it as is. Hoping that the porting and reshaping of the hotside will improve boost control. Meanwhile...





Used some vacuum hose to cover the edges of this hole. Oil filter lines will pass through here.



The end of a rather sweaty and slow-moving afternoon under the car. It's nice to be able to take my time while I work on things. So much more enjoyable than being pressured to have the car running by dinner time!

 
TB as hell. At any rate, access is excellent and the install went very well. Core support panel is sturdy enough to spin the oil filter on and off, which is nice. Oil cooler is in the stock location, albeit pushed to the side a bit. Not sure about trans cooler as the lines look hokey as hell. Hoping a manual trans swap will be the answer to clean it up.

 
YEP, that manual swap is calling your name.

I was looking for a sport for my filter relocation and wanted to mount it pointing stright down behind the radiator, unfortunately that doesn't work unless you move the IC in front of the A/C condensor. So I ended up mounting it just above the frame rail, pointing forward as a temporary solution.
 
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