I'm sure there's some reason this wouldn't work (otherwise it'd be common) but I'm trying to find holes in my theory... so I thought I'd toss it out there, put my ignorance of all things boosty on display, an maybe learn something interesting.

Stock Nikki carb flows at something around 300cfm @ 14psi (ambient) based on what I've read around here.

Doubling that (IOW, 14lb boost) is a pretty high target for a boosted engine; seems like most I've read about run far below that, on the order of 5-9 psi boost.

Being an avid diver, I'm working with high-pressure air all the time. My primary tank I'm using right now is a high-pressure steel tank holds 100 cubic feet of sea-level air, compressed to around 4300 PSI to fit in a steel tank that is about 7x28 inches, weighs about 40 lbs, and cost about $300.

7 pounds of boost into that 300cfm Nikki would equate to using about 150cfm of sea-level air, which could be run from that tank for a total of about 45 seconds of WOT operation.

That's a pretty good run time for short-track antics, don't you think?

It'd be a cold dry shot, too, since the air was compressed and dried external to the tank; expansion cooling at the nozzle would be far more effective than any intercooler could hope to be.

A tank of air from a scuba shop only costs around $5 (I get mine for $1 a fill from my club).

Is there some reason I'm missing that tanked air, suitably valved and nozzled into the intake, couldn't be used to provide cheap, effective short-punch boost compared to the relative expense and complexity of super- or turbo-charging?

Notto mention that it would be a breeze to switch in and out of a "smog-compliant" config, as you'd not even be scraping gasket materials.

OK, where'd I go wrong? Pick it apart!

 

Actually I am curious to see how this COULDN'T work, since its actually something I have wondered before...

 

Problem is you are not pumping/forcing the air in. If I understand what you are saying, you want to just dump the tank at a controlled rate (150 SCFM) into the intake. What is going to happen is the engine will just consume you scuba tank air instead of the outside air. There will be no increase in manifold pressure. In fact, if the air from the tank was flowing faster than the engine was drawing it in, the excess would actually flow out the intake into the outside world.

This would cool the intake charge a bit, so some power may be gained.

In order to make boost you need a pump of some kind inline with the airflow. That pump has to be able to supply air faster than what the engine would naturally draw in on its own.

 

You would need a bigger valve on that tank. When I empty tanks, it takes forever at wide open.

Also, you might want to try pure oxygen, that will give it much boost Good luck finding someone to fill it in the tank for you though.

 

You would need a closed system for the boost; "carb in a box", "carb hat", etc.
A lot of effort for just 45 secs, IMO. Why not set up nitrous injection?
As for using straight oxygen, DON'T! You can get small enough tanks filled easily enough. I use an oxy-acetylene setup for gold jewelry, and the Oxy tank is about 9 in diameter and 28 inches tall. But that's just crazy. If anything ever happened, it could be a real catastraphuck.

Your idea isn't dumb, and it isn't impossible, but it would be a lot of trouble to get right for awful limited bursts of power. I think you might be about right on the 45 seconds, though.

 

yeah pure oxygen could be very bad . . . this is a pretty cool idea, the only thing i can see wrong and gsl-se has already pointed it out, the two pressures will equal each other out. unless you have some way of supercharging it into it . . .

 

I was thinking of something along the line of a pressure nozzle aimed straight down the venturis. Since the additional air would be coming at high nozzle velocity & coaxial to the flow, I was thinking that you'd get a good laminar effect going that wouldn't go turbulent until further down the intake.

In effect, you'd be creating a flowing "soft venturi" composed of pressurized air, that would carry atmo air along instead of replacing it.

Leastwise, that's what the daydream looks like in my head.

Well, Nitrous has problems that straight boost doesn't, as it's an enrichment technology and changes combustion chemistry. I was thinking of it as sort of a half-step.

And nitrous costs coin every time you use it, where air fills are dirt cheap.

Oh, hell, no... I'm a child of the Space Race; I remember Apollo One. Pressurized O2 is nothing to play with around flammables!

Yeah, it would require a higher-flowrate valve than a standard scuba rig. You could maybe just mill one to a larger bore diameter, but the needle is still the limiting factor.

& 45 seconds (or even a third of that) is a looooong dragstrip run.

Like I said, I'm sure there are reasons it wouldn't work or else it wouldv'e been done before. I'm just enjoying exploring the reasons with you guys!

 

i was actually thinking about this last night..... hook a compressor to the bottle, and youd have free refills, like the people do for bagged trucks.. except, their compressors straight feed the bags now that i think about it...

 

Fact: Oxygen makes up roughly 21% of the air we breathe...

Fact: Oxygen is the main reason things burn...

Fact: 100% Oxygen exposed to an all ready occuring process of rapid oxidation (burning) = Big hot fire that don't go out easy


Lesson?

Oxygen + Fire = one hell of a Roman Candle

 

Its been done. Similar to nitrous except the gains aren't as great. Guy at I know that drag races told me he fills up his nitrous bottles with compressed air for testing and tuning because its free. The thing is N20 is over 30% oxygen, and air is about 20%. And the reason they use N20 over pure oxygen is just what Sterling touched on, Oxygen is a very volitile gas that could spell disaster.

I have some of the equipment around to do this, I've debated it, but then I've read all the crap people running turbos (or nitrous) have to go thru with timing and preventative **** to keep your motor from popping I figure my motor would appreaciate if I didn't do it.

 

as already pointed out, there would be no way to direct pressure with this setup. its a valid idea and it could be done, but you would have to have some sort of electronic "flapper" in the air intake that closes when the bottle valve opens so that the pressure would have nowhere to go but through the engine. otherwise it would be marginally more effective than a ram air scoop.

regardless, nice to see people thinking outside the box. lets strap an oxygen bottle to a lawnmower and see what happens.

 

This is what would happen. Just replace the grill with the lawnmower.

http://www.youtube.com/watch?v=TBLr_XrooLs

 

Iron and aluminum in the presence of enough oxygen, and heat, becomes thermite.

Y'know, divers do use nitrox or "enriched air" (higher partial pressure of oxygen) to increase dive times. But that's back into the mo' money category for fills, as well as having to rejet.

 

How about a rebreather for the exhaust?

 

Very cool idea. That'd be interesting to see if it could work.

 

Uhhhyep! I watched my sisters Honda burn in our driveway. That **** was NOT going out until it was finished! Particularly the engine, trany & wheels, all aluminum. It all melted and kept burning as little pools of fire right into the blacktop. It was about 5 degrees out with high winds. Plenty of oxygen.

 

Isn't that what an EGR system does?

 

people thinking of ways to improve something is always awesome . . . i've thought about having an electric turbo, that way you can just flip a switch whenever you need/want it lol

 

it wont work because there isn't enough air volume to pressureize the manifold for any legnth of time not nearly enough when you compair how much air the engine digests. Also if the idea is just an extra shot of oxygen like N20, you'd also have to add fuel of you're creating a lean situation and boom..

 

exhaust gas recirculation

 

I thought about this but insted of injecting into the intake shoot it into a turbo to spin it up faster .then I thought about using a ac compressor to a tank

 

electric clutch off of an A/c compressor on a supercharger hooked up to RPM or toggle switch.

Mad Max style, eh? I love it when someone says something Mad Max