Building the perfect 90

erover82

Well-known member
however, and this is my only critique… ditch those horrible slit compression bands and go v-band clamps on exhaust. You’ll never go back. And it always should have had the vibration sleeve…all mine did…

Critique away - easier to make improvements now than later. However, I’m not sure which clamps you mean. There’s only one clamp on the exhaust, the Norma clamp at the turbo pipe, and I’ve replaced the nut with a better copper lock nut. I also used the factory specified Loctite exhaust sealant that most people forget.

Never seen a 200 Tdi exhaust with a flex coupler, but they were standard on 300 Tdi. The rear pipe route is much more elegant as well and created space for a rear tank.
 

MountainD

Technical Excellence Contributor
I really should have said flange, but here:
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you could probably do it at the turbo too— I hate the slip clamp. Need to be a stout v clamp and most likely a nickel derivative rod like a cronacast or cronamig perhaps, but not 100% on best rod or if heat is an issue right there.

it’s entirely possible that the PO installed the flex couplers— I can guess why. I’ve only had one D that was a 200, and worked on friends which had them but were aftermarket I’m sure at that point. I used them on my R2.8 as well and I just assumed it was best practice…
 

Z.G

Well-known member
First, the shifter bushing. Jesus man, really? You make me want to disassemble my newly assembled shit. Stop it.

however, and this is my only critique… ditch those horrible slit compression bands and go v-band clamps on exhaust. You’ll never go back. And it always should have had the vibration sleeve…all mine did…
Agreed, all of them should have a vibration sleeve, but I've never seen anyone offering 200 front pipes with them, genuine as well.
 

erover82

Well-known member
Building the cooling pack

Choosing a radiator was a tough decision that came down to three options:
  • Traditional brass
    • Theoretically more durable
    • Theoretically field repairable
    • More expensive
  • Plastic / aluminum
    • Theoretically better cooling
    • Lightest
    • Least expensive
    • Questionable quality
  • Welded aluminum
    • Theoretically better cooling
    • Lighter
    • Most expensive
    • Questionable durability (weld cracks)
Ultimately it came down to a few factors
  1. Repeated observations of issues with custom welded radiators online/in person and across several vehicle makes.
  2. Fewer observations of issues with brand new LR brass radiators, but some nonetheless
  3. Feedback from vendors indicating the there had been few, if any, issues with the plastic / aluminum radiators
  4. All modern vehicles use plastic / aluminum with excellent reliability
In the end I took a chance on a plastic / aluminum radiator. I view it as an informed experiment, and I'm willing to be wrong.

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I'm not into the bright aluminum (non-OEM) look however, so first it received deoxidation and Alodine baths. You can just make out the post-process yellow tint below.

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Then into the paint tent where it received several coats of radiator enamel.

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The cooling pack frame parts had been blasted and refinished in previous batches. An Airtec double row intercooler was acquired.

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The lower frame piece was actually new as the old one was beyond efficient repair. However, this meant as it was a newer part intended for 300Tdi setups, the outlet notch was in the wrong place. Some gentle work with the die grinder fixed that issue.

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Much better

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The original intention was to fit this SPAL PWM-controlled fan into a 300Tdi shroud and revel in how elegant the solution was, except..

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I'd forgot to factor in the additional thickness of the double row intercooler. Doh!

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erover82

Well-known member
I'd come up with a few ideas to solve the shroud problem, but didn't feel great about how the solution would look. Instead, I headed off to CAD to develop my own shroud.

It took a while to get the details right - fastening strategy, pipe clearance, fan opening size, fan orientation, closing off air leaks, triple checking measurements, CNC bending limitations, etc.

I wanted a solution that included the intercooler as the factory shroud does, ensuring some airflow at low speeds. However, I wanted to do a better job at allowing maximum airflow space after the intercooler, as the factory shroud is very restrictive over the intercooler.

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All pieces back from laser cutting and bending. One edge (seen left) had to be stitch cut for manual bending, as I couldn't ensure a collision wouldn't occur in the press. The stich gaps would be sealed up later.

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Fully assembled and loosely test fitting everything. Some dimensions were just a hair off, but overall it fit great.

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Large diameter, ribbed, adhesive-backed rivet nuts for fan mounting. Made this flange bushing to ensure they collapse centrally. Otherwise, they're a pain in the ass to keep centered.

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Test fitting fan with completed rivet nuts and spacers.

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Next - disassemble, clean, prep and off to the paint booth.
 

Eliot

Well-known member
I'd come up with a few ideas to solve the shroud problem, but didn't feel great about how the solution would look. Instead, I headed off to CAD to develop my own shroud.

It took a while to get the details right - fastening strategy, pipe clearance, fan opening size, fan orientation, closing off air leaks, triple checking measurements, CNC bending limitations, etc.

I wanted a solution that included the intercooler as the factory shroud does, ensuring some airflow at low speeds. However, I wanted to do a better job at allowing maximum airflow space after the intercooler, as the factory shroud is very restrictive over the intercooler.

View attachment 26809


All pieces back from laser cutting and bending. One edge (seen left) had to be stitch cut for manual bending, as I couldn't ensure a collision wouldn't occur in the press. The stich gaps would be sealed up later.

View attachment 26810


Fully assembled and loosely test fitting everything. Some dimensions were just a hair off, but overall it fit great.

View attachment 26811


Large diameter, ribbed, adhesive-backed rivet nuts for fan mounting. Made this flange bushing to ensure they collapse centrally. Otherwise, they're a pain in the ass to keep centered.

View attachment 26812


Test fitting fan with completed rivet nuts and spacers.

View attachment 26813

Next - disassemble, clean, prep and off to the paint booth.

Sweet mother Mary.
 

erover82

Well-known member
Alodine, expoy, and semi-gloss urethane. Made a bracket to hold the fan controller too.

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Black silicone to seal the stitch cut.

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Trim seal to close any gaps. This seal profile actually fit other gaps better than the one shown, but it worked.

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Assembled

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Radiator came with O-ring type oil-cooler fittings, but I needed the flare type. Purchased a set and painted them to match/ prevent corrosion. Seen here curing under a lamp.

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Apprentice helping fit adapters and lines.

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Added a genuine decal to the shroud to give it that OEM touch.

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Restored the original rusty intercooler pipes.

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Then wondered if I could find aluminum pipes that would be lighter, wouldn't rust, and lacked the bends/pinches only needed for LHD steering boxes. After some searching I found a set of similarly sized aluminum pipes from CXRacing, which I then etched and painted as well.

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Need a few more hose clamps, but all pieces fit together well.

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KND

Well-known member
Wow, very detail photos and awesome built, Where do you get all the time? I wish, I have more time and skill.
 
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erover82

Well-known member
Where do you all the time?

Been asking the same question lately, as due to a litany of reasons it seems to have become scarce. Another factor has been the weather. We've had a relatively wet spring and the project is at a point where progress depends upon having certain parts painted. However, there are several sub-projects at various stages of completion, some stretching back years, that I hope to complete and share soon. Now that I think about it, some are completed, but waiting for the right time.

Upcoming:
  • Body paint - Much prep completed over winter/spring. Plenty of agonizing over color.
  • Front bulkhead - Changed directions
  • Rear bulkhead - Frankenstein of parts
  • Tub build up
  • More original parts restorations
  • More custom parts
  • Modified fuel system
  • And more..
 
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