Forced Air? TURBO? Options

[bob91403]

Could someone tell me why a scoop can't increase air pressure, as you go faster, and create the same kind of HP "boost" you get from turbo or superchargers? Excuse me for being ignorant. But, isn't it just a matter of increasing air pressure to the intake, and pumping in the right amount of gas for mixture? What about a pressurized tank of air, or both air and propane tanks? Couldn't you use a small compressor for boost, or as a source to refill a "boost" tank? I really don't understand this obcession with tubocharging. Nitrous systems have been around for a long time, and are much simpler. I was told, by my top rated Porsche mechanic, that, "Yeah, higher compression heads, turbocharging, supercharging, nitrous oxide, will all increase horsepower. But, anything you do to increase the horsepower will seriously lower the longevity of the engine." He doesn't even recomend european compression heads for a rebuild. I do understand, tubocharging a smaller engine gives you increased horsepower, plus the weight advantage of not having to put in a 3.2L six. But, if you have to rebuild it every 50K, instead of 150K miles, doesn't conversion cost less? Curious to hear your replies.

[SLITS]

NAP is 14.7 lbs (sea level). A turbo, in theory, could produce unlimited boost - like Formula One engines, they ran at 80+ lbs of boost - it has to do with the compressor blade and the turbine blade design + the housing.

That said, a "normal" turbo on most production engines is limited at 7-10 lbs of boost by use of a popoff or bypass valve (exhaust gasses bypass the turbine blades). They usually have a stock CR of 7 - 7.5:1

Without a popoff/wastegate, the turbo will continue to build pressure till it blows the head off the engine or blows the crank out the bottom (IMG:style_emoticons/default/ohmy.gif)

In theory if you double the AP, meaning run 14.7 lbs of boost, you double the HP of the engine.

A scoop is great for getting cold (realtive) to the engine, but not much else.

And I forgot - superchargers take HP to produce boost (5 - 7 HP wasted) - turbochargers just run off the flow of exhaust gasses.