Every good running 6.2L deserves a turbo. Banks is the only company that I know of still offering a compelete kit.
However:
All that you really need from the Banks kit is the exhaust manifold and crossover pipe. Pick your turbo from there just as long as it has a straight exit like a TE06H or a T04E.
The Banks airbox is pretty, but it's not necessary as one can fab an intake easily using pipe and a cone filter. The plenum is neat as well, but a superior piece can be hand made at a fraction of the price.
Wrapping the crossover pipe keeps heat energy inside the exhaust before the turbo, and that decreases lag and helps overall efficiency.
If I had it to do over again, I would go with the Banks exhaust, manifold, crossover pipe, turbo oil feed/drain, but fab the rest myself. That cuts a few hunderd dollars of the price tag, and in my opinion one would end up with a better setup.
The Banks kit is a perfect option for someone that just wants basic turbo power, but isn't terribly interested in tuning past that.
As for which turbo, I like my TE06H, but will probably end up using a 60-1 T04E with a .68 a/r ratio and P trim wheel. Garret and Master Power make some of these turbos. Anything with a T3 flange will bolt up.
Adjusting the fuel rate:
Before tearing into the injection pump, make sure you've got clean hands and the area around the pump is clean as well; something as small as a piece of lint can clog an injector. With the cap of the pump removed and the diesel fuel drained from the bowl, look down through the sight window for the adjustment screw. We've found that it's not necessary to remove any of the pump linkage to access the sight. Using a 5/32" Allen wrench, turn the adjusting screw to alter the fuel rate. To increase, turn clockwise; to decrease, turn counter-clockwise. We chose to use a brand new t-handle wrench since the adjustment screw turns tight, and if stripped, then it's a bad day. Banks recommended a 1/4 turn increase, so that's where we chose to start. Depending on your DB2's plunger size and RPM, different adjustments may work better.
Some pics:
http://www.oliverdiesel.com/images/6.2TD/banksturbo/db2capoffdieselcleared.JPG
http://www.oliverdiesel.com/images/6.2TD/banksturbo/adjustingfuelrate.JPG
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