Originally Posted by .boB

Ask your buddy if he's ever heard of a GMC 6-71 blower. Back in the fiftys and sixtys, hot rodders took the blower off of a diesel bus engine and adapted it to their gas engines.

TEchnology has advanced, and the belt driven blower has been left behind for most diesel applications. They are heavier, don't last as long, and are less efficient. I have seen some trick high performance and severe duty applications that have both a turbo and a belt driven blower.

The problem with a belt driven blower is that you get X boost at Y rpm. It's a fixed ratio. Loaded or unloaded, you get the same boost. And it's tough to get boost at low rpm's on a gas engine.

Watch the boost gauge on a turbo'ed anything. You get boost according to engine load. Cruising empty down the highway at 1800 rpm's you get 1-2 psi of boost. But start pulling a load up a hill, same speed and same rpm's, now you have 25-30 psi of boost.

More boost means more air volume. That increased air volume needs an increased fuel volume to keep the ratio the same. That's more important in a gas engine than in a diesel. That means the belt driven engine will burn pretty much the same fuel at that rpm regardless of load. The diesel engine will burn much less fuel, because of the lower boost.

Look at modern engine designs that are on the cutting edge - like Ford's new Ecotec engine. Lots of power, very efficient. Blower or turbo? Of course, it's a turbo.

Tell your buddy that you can easily put a blower on a diesel. But you don't want to lose that much power.