Oliver buffs: Is a Super 99 GM diesel supercharged??

Thanks!

Steven

The person below who said the supercharger was belt driven on the Detroit (GM) engines is wrong. They are driven off the accessory drive. When these "blowers" are adapted to gas engines they are usually belt driven althogh many years ago they were also positioned in tront of the engine and hooked directly to tht crank.

There are currently 5 types of superchargers. All superchargers are a form of one of the basic 5 types.

1) Roots type. These are what originally came out on the GM Detroit Diesel engines and made famous later by the Fuel (Nitro Methane) guys in the 60's. These are what dominate NHRA alcohol and nitro classes and are also widely used in monster trucks and tractor pulling. A variation of the roots blower is the screw type suprcharger like the PSI.

2) Centrifugal. These are best known from the Turbocharger which uses the remaining energy in exhaust gasses to drive a turbine wheel which is connected to a compressor wheel. The great advantage to the turbo is that it is non parasitic (draws no horsepower from the engine to drive it) and by being able to freewheel at speeds over 100,000 rpm it can have an exponential output. Another type of centrifugal super charger is the Paxton Mc Cullough which is a compressor wheel belt driven from the crank and geared up to great speed. These PMcC's were made famous by the 57 T'birds that Ford factory installed PMcC's on a few 312's.

3)Vane. These were basically drums with slots containing sliding vanes and placed in an eccentric. They were only used in low hp applications and suffered from a dire case of heat build up.

4)Axial Flow. Strange one. Basically the compressor section of a jet engine that is belt driven off the crank. Very rare, expensive, and difficult to adapt to an engine. But they say the sound alone is worth all the trouble and expense.

5) Comprex Pressure Wave Supercharger. Developed in the 70's by Brown & Boveri in Europe for use on diesel engines. Uses pulses from the exhaust to directly push air to the cylinders. Although it is belt driven it is basically non parasitic as the belt is used only to keep the unit in time with the engine. The output is close to being on par with a turbo but actually has a little more bottom end torque but gives up a little on the top end. The unit isn't widely used because of its cost and difficulty to plumb correctly to the enigine. The placement is difficult because of the need to have a short direct path for the passage of air from the unit to the intake.

By the way the Detroits were available from the factory with turbos for higher output applications.

The largest Detriot I've been around was 16V92T. That designation breaks down to 16 cylinder, V configuation, 92 cubic inches per cylinder and turbocharged. This one was basically two 8V92's cast into one block. The engine had two roots blowers and four turbos to on it and was driving a really large generator.

I've also worked on EMD's that are also built by GM, almost identical in design to the Detroit, but are gigantic in size. Largest I've seen was twenty cylinders, 715 cubic inches per cylinder for a total of 14,300 CID and about 6000 hp.

The Detroit has no way to move air to the cylinders nor to push the exhaust from the cylinders without the supercharger.

The Detroit does not have a sealed crankcase like a conventional 2 stroke gas motor which uses the piston movement to precharge the crankcase and push it into the cylinder on the next stoke through a transfer port. The Detroit does however have 4 exhaust valves (some have only 2) and since the blower pushes no fuel, just air. at the lower part of the stroke the exhaust valves are open and the air rushing in through the intake ports in the cylinder push the exhaust out the top. the exhaust valves close when the piston about passes the top of the intake ports and allows compression to begin followed by fuel injection near TDC.

One of the other things unique to the Detroit design is the small end of the rod is rather spindly if it even is there at all. Some of the larger Detroits actually bolt the rod to the bottom of the piston pin. The rod in the detroit is always in compression, except during start up and only needs to be strong enough at the wrist pin to move the pistons to start.

Hope this information is helpful.