The Silent Service
What I have been looking for in a turbocharger, and what the aftermarket vendors offer for my build are two very different things. About two years ago I started doing the research and seeking out a few experienced members on the ORG and other sites to build a one-of custom ‘charger with the explicit intentions of handling the air challenges of the higher altitudes while towing. Further I intended this turbo to be compatible with Fords stock programming and strategies, just to see if it could be done.
I wouldn’t be happy with just any Powermax turbo swap, unfortunately the whistle of the ’03 6.0Ls and the Powermax 10-blades isn’t what I am looking for here. So we’re keeping the 13 blades, both for early spooling, and my sanity.
It has become a standard in the 6.0L community that the 63.5x88mm – 64x92mm compressors are the largest one can really run with for stock injectors. I’ve matched that airflow to the largest 13 blade turbine shaft that I am aware of that will fit in the 6.0L single VGT’s. Depending on variables collected once this turbo is dialed in, I may attempt a second version with an even larger compressor wheel after an upgrade of injectors.
I selected a Garrett 6.0L Powermax turbo (GT3788VA) as the foundation for this build. It gave me a larger exhaust housing and vanes to assist in maximizing airflow over simply upgrading the compressor side only of my stock unit. When weighing the options and cost between the Powermax and upgrading the vanes of the stock unit for around, I felt the additional expense would pay off.
Next was the selection of the compressor and housing, and though the original plan has always been a Garrett GT4088 slapped into the front end, I ended up finding Charlie and KC Turbos after my search for an affordable GT4088 came up short. I went logically to their Stage 2 DIY Kit which includes 64x88mm 11-blade single plane compressor wheel, matched to a unique .72A/R race housing with drilled silencing ring.
The DIY kit from KC Turbos also included the 360* Thrust Bearing rebuild kit. At the same time I added the option of stainless steel Unison ring offered by KC Turbos to complement the build, and avoid future issues.
Here’s where the build may get some push back, and it went a different direction than most might expect. This turbo still has a 13-Blade exhaust turbine to aid in spooling this turbo up early in the RPM band. It turns out that Duramax crowd have been swapping Powermax exhaust turbines into their LLY 6.6L for a while, and the reverse is being applied here with a new OEM replacement turbine.
How the Powermax compares:
Stock: 57x82mm Cast wheel, 6 single plane blade.
Powermax: 63.5x88mm Cast wheel, 12 dual plane blades. Blade depth: 29.6mm/22.2mm
KC Turbos: 64x88mm Bilit wheel with tips extended out to about 92mm, 11 single plane blades. Blade depth: 36.5mm
Stock: .58 A/R for a 57x88mm wheel. Stock Silencing shroud.
Powermax: .58 A/R for a 63.5x88mm wheel. Garrett Silencing Ring.
KC Turbos: .72 A/R for a 654.88mm wheel. Drilled Silencing Ring.
Stock: 64x72mm, 13 Blade.
Powermax: 66.8x72.5mm, 10 Blade, 0.76mm thick.
DMAX LLY: 66.5x72.5mm, 13 Blade, 0.88mm thick.
Powermax: Steel, 5.56mm thick
KC Turbos: Stainless Steel, 5.48mm thick
NOTE: Still working on getting the turbo put together, I know you all want to see the pictures – and I’ll post those later this weekend.
Though not meant as a technical step-by-step procedure on the modifications to turn a Powermax turbo as listed. I can provide the source that I used in referencing as I conducted the rebuild upon request. Basically, if you follow the thread referenced above, and you omit the steps concerning the cleaning of the internals you will be able to handle this job.
Site the Rebuild Thread:
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