Damien00677

So one of the guys on here (TekViper) threw an idea at me earlier. What if we were to shoot a blast of compressed air down the intake. What if we would hook a hose or a few hoses to the intake somewhere (will probably need to be before the MAF) and shoot this blast of air into the engine. What kind of pressure would be needed to make any kind of boost. On a side note, I think it would be cool to shoot the air through 6 hoses down through the six seperate passages in the upper plenum so there would be a more direct shot of the air. I don't konw how functional that would be since i think it would cause the car to run lean as a result of no extra fuel going into the engine with the extra air. Also, I don't know how functional it would be but it would be cool to do the same thing just lower pressure and with good old propane. How realistic would all this be (mostly wondering about the first idea since the other ones are kinda outlandish)

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TomP

You'd need a lot of compressed air... don't forget about the volume needed.

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-Tom P (Hot rodded 1986 Firebird 2.8l)

MrDude_1

thats exactly how nitrous systems work.


the prob with compressed air is the volume needed.

a engine sucks ALOT of air.

the solution to this is to use less air, but have a higher oxygen content.
now if you used pure oxygen, you would burn a hole in the pistion quite quickly.

so you need somthing to stablize it..... like nitrogen..

thats why we use nitrous instead of air or oxygen... you can shoot some(with the approperate amount of fuel) and get more power without overheating everything.

Damien00677

i guess i didn't realize the amount of air needed.
Just out of curiosity could some body show me the calculations to find how much air our cars suck in and how much extra we'd need for say 7 psi of boost

I'm not doubting you guys or anything, just trying to further my knowledge of physics
So if some kind of genius on these boards could write all that out for me or even email it to me that would be great

Mark305TBI

Well, since this is the V6 board, let's use a 2.8L engine for our example. Volumetric efficiency for most street engines is about 80%, which means in one full rotation, the engine would ingest 2.24 litres of air. That's 13,440 litres a minute at 6000 rpms.

Atmospheric pressure is 14.7 psi, so to get 7 psi of boost (21.7 psi), you would have to cram 1.48 (21.7 / 14.7) times as much air into the engine. In one rotation, at 7 pounds of boost, your engine would ingest 4.14 (2.8 * 1.48) litres of air. Let's say you want to spin your engine to 6000 rpm. That's 24,864 litres in a minute. Better have a big compressed air tank .

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Damien00677

cool thanks

The_Raven

This idea was tried, way back in the '60s, when everybody had ideas and actually tried them out. Some were pretty far fetched, and some even worked. LOL

Anywaythe one car that comes to mind using the static compressed air theory (stored compressed air in a tank), was a rail, that I have or at least had a picture of, and a small article on. The rail was longer than any other rail of the time due to the volumn of air needed, I don't remeber the exact dimentions, but the tank was very large. The main poblem was storing enough compressed air for a full 1/4 mile run at a constant pressure. The testing of the rail showed that it ran out of stored air (high pressure) before the end of the run, I think they actually figured out they needed a tank with about twice the volumn to have a full run, which would have been way too long to actually use, and would also be quite a bit heavier, the needs then went up, and so on. It's kinda hard to explain, but if you want forced induction nothing beats turbo or supercharging, this is what they were designed to do.

Project: 85 2.8 bird

This sounds vaguely familiar..............

any way, if you shot the air down through the runners, you would create a lean sitiation.

AM91Camaro_RS

i have a slightly different idea but along the same lines... what about using a single NOS fogger in the intake tube but spraying racing alchol (not beer, sorry). racing alcohol would be a little safer to carry and probably less harmfull for the engine. plus, spraying a fuel doesn't require the injectors giving more fuel. possiblity??

The_Raven

That sounds a LOT like water/alcohol injection, used on forced induction engines mostly.

NHRATA01

Right, though I believe he is implying combusting the alcohol, whereas in FI setups it is used more for cooling the combustion chamber to prevent detonation. Which I think are different alcohols anyways - racing is nitromethane, but I don't think that is the same alcohol that FI guys use (I think methanol?) I'm not sure you could combust gasoline and alcohol under similar condtions in the cylinder. Alcohol is used in drag cars because it requires less air vs. gasoline for combustion. IE gasoline requires ~12 parts air for every 1 part gasoline - with alcohol the amount of air is less, allowing you to combust more alcohol (hence make more power) within the same displacement.

Brian Felts

The phase change when the alcohol changes from a liquid to a gas in route to the combustion chamber lowers the air temp of the incoming charge. This is why its very important to use a good pump and nozzle to get a infe mist. Then the alcohol also ups the octane rating of the fuel you are using. Combe more octane and lower temps and you can run more boost and more timing.

SSC

Its been done a long time ago. People would use rubbing alcohol with a small pump and inject it into the engine like a N2O system poor mans NOS. It does work but it looks like a home made meth lab setup in your car. Much easyer to go with a real N20 setup and forget about it.

__________________
1982 Firebird 350/700R4.
Crower Beast cam, RPM Intake, Edelcrap 1406 for the street, 14x3 open element air cleaner, Serpentine conversion, Carter rotary pump, Flowtech Headers 3" exh, cat delete with Ravin muffler. Modified B&M / Transgo shift kit with B&M cooler.

1995 Camaro T-tops 3.4l/4L60. Stock as can be.

D M N

Hey can you give more details i want to try it also how much rubbing alchol would you need for a couple 1/4 mile runs