With our fuel turned up, nitrous...
With our fuel turned up, nitrous armed, and compressor upgraded, we were ready to roll. After the chassis dyno stopped spinning, we were rewarded with 340 horsepower at the wheels, with nitrous. Torque jumped from 601 lb-ft to 691 lb-ft. Since we were hoping for more, we'll continue to fiddle with the truck on the dyno in the coming months in hopes of breaking the 400hp mark.
We were looking for a cheap way to make more power on Project Rust Bucket, so we started looking into compressor upgrades. A compressor upgrade is basically where the front half of the turbocharger is replaced, which means you'll get a new compressor wheel, as well as a new housing. We figured this should make more power, but there are also a bunch of other fringe benefits that we hadn't initially thought of. In no particular order, we'll delve into them now.
More Airflow
This might be the obvious one, but a turbo that moves more air can really be helpful for an engine that is overfueled, or has no intercooler like our '89 Dodge. Providing the fuel can keep up, more air also equals more boost and more power.
Efficiency
Our new compressor wheel measured 60mm instead of the stock 56mm version, so that is where the extra airflow comes from. But the larger wheel also has a more efficient design, which means quicker spooling, and more boost. Improved efficiency means the air moved by the turbocharger is often cooler, which will increase power and decrease exhaust gas temperatures. We saw proof of this efficiency in our upgrade, as the larger wheel gave us an extra 5 psi of boost at the same fuel setting, as well as a 100-degree drop in EGTs.
 To start, our old turbo needed...  To start, our old turbo needed to come off, which required unbolting it from the exhaust manifold, as well as removing the downpipe. |  Next was the intake, as well...  Next was the intake, as well as the compressor discharge hose. Nothing tricky yet, just simple hand tool stuff. |  Finally, the oil drain was...  Finally, the oil drain was removed, and the turbocharger could be removed from the engine. |