I was just thinking, which can be dangerous sometimes, but I had a thought. If turbos and superchargers just force more air into your engine, couldn't you just plumb in some compressed air? I imagine you would need a compressor that could keep up with the motor, or a tank that holds enough to get you down the track if thats what you are after. I don't know much if anything about turbos/supers, so I may be just crazy, but like I said it was just a thought. Any feedback would be welcome.

 

That's what a supercharger/turbocharger ultimately is - an air compressor.

The difference is your home air compressor provides 15 cfm @ 40psi, and a supercharger could provide 10psi, but at 500-800 cfm.

Pressure is nice.... that's what forced induction is about... but you need the cfm to keep up that pressure with the engine.

Just some random numbers to illustrate the point. Obviously a 1.8L would need less cfm at 10psi than a 500cid engine.

 

That makes sense, thanks. I can put that thought to rest now.

 

Yeah, it would be nice, but you'd waste the weight in keeping the onboard tank setup to what you want, if you could regulate the output to get the desired result. Although this is very similar to giggle gas in thought. It's just that nitrous provides more bang than simple compressed air.

-Kerry

 

Adding forced induction of any kind increases the amount of ambient air in the engine, which in turn increases the amount of oxygen since there is oxygen in ambient air. Take a deep breath See? Oxygen!

More available oxygen allows us to inject and burn more fuel, to keep the optimum air/fuel ratio for a given RPM/load.

Nitrous Oxide has two nitrogen molecules and one oxygen molecule, and under heat and pressure it breaks apart very easily, and of course combustion engines have plenty of pressure and heat.

So that leaves additional oxygen molecules floating around in the piston chambers, just waiting to help additional fuel burn. So guess what - we add more fuel to an engine that's "on the bottle" and magically we have more power.

The advantage of nitrous oxide injection is that the overall pressure inside the engine isn't significantly increased. If your engine is a 10:1 ratio, with a 250HP shot of nitrious your virtual C/R is still very close to that. The drawback is obviously that the bottle empties and requires filling.

Superchargers and turbochargers provide this additional oxygen by pumping more ambient air which of course contains oxygen. The atmosphere is made up of 78% nitrogen, 21% oxygen, and the remaining 1% is other gasis which include argon, neon, helium, krypton, xenon, hydrogen, carbon dioxide, methane, nitrous oxide, water vapor and ozone.

So if ambient air is 21% oxygen by volume, and you double the pressure (1 bar or 14.7psi) you've doubled the oxygen volume in the engine - which means you can double the fuel to maintain the proper a/f ratio. More air/fuel, more power.

The drawback of supercharging/turbocharging of course is complexity, maintanence, additional weight, and of course the engine has to be engineered and built to operate at the much higher pressures.

Ask anyone who has a piston with a hole in it as a paper weight

Now, we can think about more interesting things. Here is the basic formula of gasoline burning, ignoring all the other irrelevent molecules.



Like with most math formulas, you can increase the left by a factor, and the right side (output) will increase by the same factor. More gasoline/air, more carbon dioxide and water. And, more power.

I think gasoline sucks. I burn a lot of it in the various vehicles I own(ed) over the years. In mowers, generators, weedwhackers, and other things.

I think the answer is hydrogen and oxygen, injected at a 2:1 ratio, which after it explodes the output will be H2O - water. No carbon.

And it's easy (but not cheap) to make your own hydrogen:

Making Hydrogen

Collecting Hydrogen

One can also buy hydrogen in tanks, like any other gas, though I'm not sure of the paperwork requirement or if permits are necessary. A friend of mine "obtained" some hydrogen from his employer into several disposable propane cylinders, which probably wasn't the smartest thing we've done, but we did feed it through a check valve into a lawnmower engine with tremendous, overspeeding to destruction results.

I like.

 

The problem with hydrogen is it typically costs more power to produce it than you gain, and it has far less usable energy per volume than gas. Like it or not, hydrocarbons have huge power to weight advantages.

 

I don't disagree.

I just like experimenting and blowing stuff up!

 

I need more time to do that... it takes me forever to clean up.

-Kerry

 

I always had the same kind of thought...except grab an oxygen tank from an oxy-axcetalyne torch and inject it into the intake lol.

 

That works absolutely fine Pud. You can even use NOS parts to achieve this.

Just make sure you REALLY pay attention to how much additional fuel you add!

 

yeah you would have to add alot more fuel if you dumped straight O2 in there. I wonder what the ratio would be?...and if you matched the line size and used propane instead of gasoline if using the ratio in PSI would be adequate. VERY hypothetical example of what I mean by that: 1psi O2 : 2psi LPG.
Oh man, I got another Im itching to try now...like redneck nitrous, lol welding truck nitrous.