Turbocharging
 
 
A couple of my rigs have been turbo'ed. I've been there and done that, so I will put my link  here in case anyone out there gets stuck on turbo problems. If I can't help, I can link you up with help.
 
 
The reason: diesel turbochargers do NOT have compressor inlet bearing seals.
The vacuum from a carburetor will draw lube oil through the compressor bearing seal until the crankcase runs out of oil!!
 
A waste gate does more than just control the manifold pressure. It will spool up the turbine much faster at low RPM and make torque earlier. You can leave your foot in the throttle without turbine runaway. The extra expense is worth every penny. With no waste gate at all, you have to size the turbine housing A/R ratio for maximum pressure, and then you have to "ramrod" the engine to make power. The torque will lack at the lower RPM range too.
 
The oil gets "whipped" into cream on it's way through bearings spinning at 65,000 RPM.
A small return line will cause oil to backup in the tube, and oil starve the bearings.
 
 
Turbochargers by Hugh MacInnes
Turbochargers  by Hugh MacInnes
 Turbo City, Orange California
 
I've done business with Turbo City for years. They know their stuff, and ship fast.
 
 
Toyota Land Cruiser Turbo
My first turbo setup
 
It made lots of power, but I had to buy fuel at the airport. It ran 25-30 PSI in the manifold on 130 octane, and made enough HP to twist drive lines into pretzels. I never had it dyno'ed, but I could run 70 MPH through sand dunes. 500 HP would probably be a conservative guess. It sounded like a logging truck when it wound up under load. I cut a hole in the front left corner of the hood for the air cleaner. With the hood closed, the offset air intake looked a bit strange. When I ran it off road in the dunes, everyone would be dying to see what was under its hood. This was a blow-through setup using an Impco inlet control valve. Note the chrome pipe from the compressor outlet to the Impco inlet. This is is a 2"  supply pipe for an old style toilet. As soon as friends found that out, it was forever known as the "Toilet-ah Land Cruiser."
 
 
 
This was my second turbo setup. It's a Dodge Power Wagon 4x4.
Turbocharged 318 front viewTurbocharged 318 side view
318 CID with a Carter 2 BBL carburetor, mounted on a homemade drop-down inlet tube. It has a water jacket pipe through the center to prevent icing. The 500 CFM  carb isn't a problem, because air is forcibly pumped through it. The rating applys for naturally aspirated engines.
 
This was a fun truck to own. It's one of the few 4x4 pickups that needs 'S' rated tires. We did a test run once on a back road. The speedo only goes to 85 and was long since pegged when the bug shield tore off and scraped over the windshield on it's way to oblivion. My friend and I thought we were dead for a split second!

This one is set up with a waste gate that keeps it at 7 PSI, and makes full pressure at 1,200 RPM. It's a trailer towing dream. Listening in on a CB radio is great while going up mountain passes at the speed limit while towing a 24' Prowler trailer. "My God! What's in that truck?" This, of course, coming from a trucker doing 15 MPH and belching black smoke, on Pipe Stone Pass.
 
 

Miscellaneous
You can expect 20-30% more horsepower without doing anything special to the engine. More than that amount, and you will have to start beefing it up internally.

If you have an engine with a turbo and you hear loud knocking - you have about 2 seconds to get off the gas pedal. Pre ignition with manifold pressure will take out a head gasket in a jiffy.

An odd thing about a turbocharged engine, is the turbine whine from one end, and the "siren" from the front. When the Dodge engine is getting it on, it sounds like a police car with a huge four barrel sucking air and running code. The compressor has about 1/2 the blades than the turbine, and the low pitch whine is from lots of air being pulled into the compressor.

Another thing, and this may be hard to believe, but the MPG will generally get better. (assuming you can keep your foot out of it) The turbo makes the engine more efficient in several ways. One is the compressor "chops up" the air/fuel mixture, and distribution to each cylinder is better. The manifold pressure "sweeps" the old air out through the exhaust valves and makes for much better mixture in the cylinders. This is done even better than four valve heads can do, because they still depend on vacuum flow from the decending piston to fill the cylinder.

Back pressure on the exhaust from the turbine isn't the problem some people think, because intake pressure will always be higher than exhaust pressure in a well matched turbo setup.

The best I ever got with the Dodge on a trip to Spokane, was 29.5 MPG. I actually drove the speed limit, and had a tail wind, but it's still a heavy full size 4x4 truck. It's a 200 mile trip from here. It gets about 12 -14 MPG pulling a big trailer.

Another nice thing about turbos, is on mountain passes, when every other engine is down as much as 20%, the turbocharged engine is still pumping out 98% of its sea level power.

The RPM limit will be higher. The Land Cruiser would easily rev to 6,500+ and be smooth as silk. Before the turbo, 4,000 RPM would feel like it was about to throw rods through the block. This is with a 262 cube inline six! Pressure from the manifold tends to help push the pistons down while they are in the intake stroke, and balance things out.

Turbo's don't run at 100,000+ RPM contrary to popular belief. They won't last long doing that. More along the lines of 60,000 to 70,000 RPM.  Compressor maps usually show the best efficiency zone between 60,000 and 80,000.

A turbocharger running at full speed, can produce more internal horsepower than the engine is putting out at the crankshaft.

According to a Pratt & Whitney manual I have, about 75% of the output of an aircraft jet engine is used to drive its own compressors. A turboprop with 2,000 SHP at the output shaft, will be making 1,500 HP internally just to run it's own compressors!
 

 
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