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Frank Grunthaler and myself have been discussing his 2.0 Audi turbo project and also mulling over Vanagon diesel engine mount substitutes. On these pages I'll post Franks comments and pictures and I hope get some comments and suggestions about the two projects.

Is it necessary to say that the text and pictures included on these pages are copywrite Frank Grunthaler?

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August 18, 2003

...There are several developments on the Vanagon front (or rear more accurately). I'm on a roll trying to finish up the Turbo Audi details and to get the engine in.

I just posted a comment on the exhaust manifold. The Audi 80 with single port exhaust fits nicely (no room to spare and the same relieving of the mount that you encountered.). The SAAB exhaust looks like it was designed for this application. Quick right angle and then into a 2 7/8 exhaust pipe. I had to extend one of the flange tips at a bolt hole. Fortunately I had a good cast iron specialist weld on the addition. The adapter flange fits like a glove. I've ported the manifold (just smoothed the interior surface and matched the final exhaust port to the adapter flange and T3 turbo inlet. Next step is ceramic coating
and the exhaust system is done.

I have solved the engine mount problem. I have a simple mod to add the SAAB hydraulic mounts, while keeping the aluminum mounts at the same place. The change can be reversed if for any reason one would want to go back to the original diesel mounts. I've slotted the original carrier right at the internal base of the reinforced segment that is welded to the carrier. I cut a vertical clearance cut up from the frame that anchors the crossstrap to intersect the upper cut at 90 degrees. As a result, the SAAB mount slides in to the carrier. I then welded hefty l-brackets on the flat side of the carrier cage to bolt in the SAAB mount. I then made a spacer ti thread down on the SAAB mount post and added a M10 stud (pinned) to the top to the same height as the VW mount. Even added a locating pin for the VW mount. The top surface of the spacer is now exactly at the top surface of the former VW mount. Even with the SAAB retainer bars (safety feature least the hydraulic mount break apart) there are no clearance issues with the mount or manifold. I should be able to mount the carriers on the existing 1.8 setup as early as next weekend. I'll do a vibration frequency spectrum test before I announce completion.

I'm also finishing a baffled oil pan system to control oil better. The basic diesel pan is a terrible design as oil just sloshes everywhere. Found a way to fit the internal cover and trapdoor assembly to the windage tray. I placed the antisloshing baffle at 0.250 inches above the full oil static level. The system uses the new pickup tube I designed to get closer to the regular VW water-cooled system. Also completed the oil introduction tube redesign and fab. This
incorporates an oil level sensor that tells me the mean oil level in the pan and warns at a level equivalent to the old add oil mark. This system lets me use the license plate door filling mechanism even with the belt driven scavenger pump. Still use the center mounted TD oil dipstick level.

Completed the redesigned fuel rail for the Audi manifold with Bosch injectors and variable fuel pressure regulator and fuel pressure sender. I'm using a G60 throttle body with integral mechanical bypass circuit so turbo boost only comes on at 5 degrees before full throttle. No turbo overrun problems.

Still using the dual oil filter system with thermostatically controlled external oil cooler from the Audi 5000T. Made a new oil filter mount flange that lets me use the oil to water heat exchanger as well.

August 23, 2003

Nonetheless I thought I'd use this question to add some comments regarding turbo manifolds and turbo conversions on I4 engines for Vanagon use, whether gas or diesel.

I have obtained and studied the Quantum TD manifold (cited here), the regular stock Golf/Jetta TD manifold, the Audi 5000 TD manifold, the Golf/Jetta single downdraft gas manifold, the Golf/Jetta dual downdraft (4 and 6 bolt flange) gas manifold, the Audi 80 single and dual downdraft gas manifolds and the ATP aftermarket 8V turbo exhaust manifold. I have examined all from the perspective of turbocharging my Audi 3A 2.0L 8V engine. There are several issues.

Simple mount interference questions:

1. For diesel engines using the original VW/KKK or Garret turbochargers, the quantum TD manifold will fit with an airflow quenching inlet tube (rubber) to jog around the close Vanagon engine mount. Turbo oil return is below the static oil level in the pan. Short life predicted despite factory Vanagon TD configuration.

2. Again for diesels, the golf/jetta manifold will clear with minor machining. I believe it works best inverted and places the turbo oil return in the right configuration for simple gravity drainage to the oil sump. Details need to be checked as I'm doing this from ancient memory and haven't looked at the diesel configuration in several years. The clearance key here is the diesel intake manifold.

(Comments 1 and 2 related to use of either the Quantum TD intake or the Golf/Jetta TD intake configuration.)

3. The Quantum TD manifold needs an adapter to mount a Garrett T3 turbo for a gasoline motor application and the Vanagon stock mount must be extensively modified or a custom design used (see archives for several solutions). Oil drain problem persists. Custom inlet and exhaust fab required. Machining of Quantum TD manifold required for clearance with any gas intake manifold.

4. The Golf/Jetta TD manifold requires the turbo to be mounted below the horizontal axis of the manifold because of the intake manifold bulk and causes severe interference with the Vanagon engine mount.

5. The Audi 5000 TD manifold strongly interferes with the engine mount.

6. The aftermarket ATP 8V turbo manifold strongly interferes with the Vanagon engine mount.

(For 4-6 a custom engine mount is the only solution and in some cases, the engine cradle and motor mount point must be changed.)

7. The gasoline exhaust manifolds for the Golf/Jetta including the single and dual downdraft units can be fitted with flange adapters, but the turbo mounts low, the oil return problem remains and exhaust and intake plumbing is a nightmare.

8. The Audi 80 gasoline manifolds are unusual in that the downpipe flange face is actually about 45 degrees from the horizontal plane of the manifold (in contrast to the parallel location in the Quantum TD and the other gasoline manifolds). With an appropriate flange adapter, one can mount a T3 turbo level in the true horizontal plane of the vehicle. The turbo is perpendicular to the long axis of the block. Oil return remains low. The turbo inlet now faces the block requiring a short radius coupling. In my configuration, the exhaust downpipe from a SAAB 900T fits perfectly, directing the exhaust path to the front of the vehicle with no interference with engine cradle, engine mount or motor mount. I'm currently porting the single downdraft Audi 80 manifold and should have installed pictures available soon.

But, the proper choice of manifold requires assessment of more than just interference!

The questions of flow and of thermal stresses are critical. Of all the manifolds discussed above, the flow through the Quantum TD is literally the worst - even worse than the standard Golf/Jetta single downdraft ball mount. The highest flow was obtained with the Audi 80 dual downdraft manifold. The Audi 80 single downdraft tied with the 6 bolt Golf/Jetta dual downdraft. These results were qualitative (taken on my crude airflow bench).

The next (and arguably most important issue) is that of thermal stresses. For both gas and diesel applications, the manifold can glow red. In the case of the diesel, the Quantum TD manifold glows for an area of 3 to 5 inches back to the head from the turbo mount flange. For gasoline engines, the whole manifold is emitting. Manifold casting thickness of the Quantum manifold is significantly less than the G/J TD and the gas turbo manifolds but similar to the G/J single downdraft unit. Extensive cracking is found with the G/J unit and similar problems have been reported with the Quantum manifold with gasoline applications. The Audi 80 manifolds are far more massive than any of the VW counterparts.

In conclusion, the Audi 4 to 2 manifold would be the optimal choice for non-turbo gas engines or for turbogas engines using the split input turbines like the T4. The optimal turbocharged system (my POV) is the single downdraft (California emission spec) Audi 80 manifold. The single outlet tube matches the input area for the T3 turbine and the adapter flange shows no reduction in flow. I would also council the use of interior and external ceramic coatings to minimize heat load on the engine and engine compartment.

October 26, 2003

Finally got around to taking some pictures. I enclose the modified vanagon diesel mount to accommodate the SAAB hydraulic mounts. You should be able to see everything, including the cuts I made to keep the stabilizing bar and to retain the SAAB mount. The adapter wings are chosen to be able to reversibly return to the diesel mounts if necessary. The SS adapter spacer is threaded for the SAAB mount stud on the bottom and for the VW stud on the top. Don't have the anti-rotation 6 mm bolt hole threaded or drilled yet. The top surface of the mount spacer is placed at the same location as the top mount surface of the standard diesel mount.

I also enclosed the photos of the single hole Audi 3A manifold, modified with the adapter for the mounting of the Garrett T3 turbo from the SAAB 9000T. When mounted on the adapter plate/manifold, the shaft axis of the turbo is horizontal (with the block mounted at the standard Vanagon diesel angle of 55 degrees) and perpendicular to the surface of the block. The Compressor is parallel to the block surface. The SAAB 900 downpipe drops down from the wastegate/exhaust exit cleanly missing the engine cradle and directed to the front of the vehicle. No mod needed for the AL engine mounts or for the hydraulic mounts.

More pictures as I finish the sump and intake manifold.