In these pictures, you can see a few details of the engine. To most any "techie" they're self-explanatory, but for you non-techie types, I'll explain a bit.

The top left shows the location of the turbocharger. It sits atop the crossover pipe, mounted onto a bracket that's welded to the crossover pipe. Through this, the exhaust flows into the turbine housing exhaust inlet.

Top right, is simply the assembled engine on the motor stand. You can see the tuned intake runners, and undrstand how this engine has so much torque. The intake runners cross between each other and service the oppsite cylinder bank they appear above. Long runners lower the speed at which a "ram tuning" effect is noticeable. In english, all I'm saying is the longer the air tube between the air plenum, and the intake valve, the "better" the engine runs (to a point...). You can also see the crappy "rubber plug" oilcap. It leaks.

The middle two show the "short block." The deep dish in the center of the piston heads allows for a reduced compresion ratio, so the engine can handle the boost without excesive detonation. The bottom end is basically stock, except for a high volime/ high pressure Melling oilpump. Some astute GM techs will probably notice the reluctor ring in the middle of the crankshaft. It's as useful as one hand clapping, because my block doesn't even have the boss for the hole for a crankshaft position sensor! The crank came from a 3.1 I found junked out at the junkyard, which had DIS ignition, and my engine has a distributor.

Bottom left is the car after painting, before engine installation. Bottom right shows the turbocharger and head closeup. The heads are the best flowing factory iron 60º heads. They came from a Cavalier Z24, and have significantly larger valves than the lo-perf engines. In english, this amounts to more top end power, because the engine can flow more air through bigger valves. Not to mention, it has 8 psi of turbo boost forcing air into it!

A turbo is a type of supercharger, meaning it puts more air pressure into the engine's intake than atmospheric pressure alone can. This results in a dramatic increase in engine power. Turbos take the power to pump air from the heat and pressure of the engine's exhaust. Since exhaust increases with power, the turbo would continue increasing boost until smething failed, so it has a wastegate valve that bleeds off the extra exhaust to keep power at a safe level. This turbo is a Rajay 370. Rajay isn't in production anymore, so once it fails beynd rebuilding, I'll replace it with a Garrett. The turbine and compressor wheels, inside the turbo spin upwards of 100,000 rpm, when the turbo is "spooled up" and producing boost.

The turbo has a special 2 layer sleeve bearing. The oil films between each layer help keep the turbo spinning smoothly, and damp high frequency vibration, but the oil is heated up by the red-hot turbine shaft. This car has an oil cooler in it to combat oil breakdown, but regular oilchanges are an especially importnt part of turbocharged car maintenance. The only other maintenence of a turbo is keeping plunbing tight, and periodic inspection of the oil supply line and bearing feed slots to make sure burned, dried up oil isn't building up there. Use of a good quality turbo-approved oil is essential. I prefer Chervon's Delo multigrade oil. Aside from foreign objects entering the turbo, or a wastegate malfunction, lubrication failure is the only real cause of turbo failure.

The turbo only spools to high speeds when the engine is under a load, and at idle it barely turns. This engine builds up oilpressure in less than 2 seconds, even from an empty filter after an oilchange. So there's no special startup procedure needed after oilchanges with this car. Any engine that automatically revs up immediately when started (such as stationary governed diesels) needs to have the oiling system pre-primed before startup, because a turbo will typically seize in under 3 seconds if it spools to boost without oil pressure.

I recently disassembled and inspected the turbo bearing, after 30k miles of this type treatment. There was no evidence of shaft or bearing wear. You do the math, it's been started with an empty oilfilter every 4000 miles for 30,000.

The other "issue" with turbo engines is shutdown procedure. The turbocharger shaft has a turbine impeller welded to one end, that literally glows red hot during operation. Lots of heat is conducted into the shaft, and oil will rapidly burn to hard sooty deposits if it stays in contact with the shaft too long. If the turbo has been recently spooled up, it needs to have the engine idling, with oil flowing over the shaft for a minute or two before shutdown. This so the shaft will cool off and not glue its self in the bearing with cooked oil, or clog the oil supply line with cooked oil deposits. Some turbos have a water jacket which allows engine coolant to keep the housing cool, circumventing the need for an elaborate shutdown procedure. This turbo is not water cooled, but when it dies, its replacement will be.

You can buy a "turbo timer" which keps the engine running for a little while after you turn off the key, based on how recently it detected turbo boost. Eventually I plan to add one to this car.

If anyone's thinking about adding a turbo to their car, be forewarned, it's a very involved project, but the power increase is incredible. Don't consider it unless you have a second car to drive as you work the bugs out of the system. Was it worth it? Yes, especially when some highschool boy racer in a lowered pickup with a 4 inch ehcaust tip is beside me at a red light, playing hideous music too loud... The following 5 seconds after the light turns green make it all worth the while! :-)