Single Engine Speed Increase Tecniques

[DGdaPilot]

You mean a RATO bottle?

Sorry, I couldn't resist.

 

[Rogue5]

Why not just take a tip from the guys who race at Reno and just reduce drag as much as is humanly possible...

 

[troy]

correct me if I'm wrong, but I believe that the percentage of 02 remains the same with an increase in altitude. What decreases is the atmosperic pressure. Less dense air means less 02 per piston stroke/less air per blade revolution/etc. That is why turbo/superchargers are so common with high perfomance engines and standard O2 delivery systems don't work at extremely high altitudes.

 

[TDTURBO]

correct me if I'm wrong, but I believe that the percentage of 02 remains the same with an increase in altitude. What decreases is the atmosperic pressure. Less dense air means less 02 per piston stroke/less air per blade revolution/etc. That is why turbo/superchargers are so common with high perfomance engines and standard O2 delivery systems don't work at extremely high altitudes.

Troy,

That was the whole gist of my question. Since a normally aspirated engine at altitude is "starving" for air, why wouldn't adding O2 improve performance? I realize turbos and superchargers are the answer but I was thinking of a simpler solution and you just answered it.

Thanks!

 

[A Squared]

Troy,

That was the whole gist of my question. Since a normally aspirated engine at altitude is "starving" for air, why wouldn't adding O2 improve performance? I realize turbos and superchargers are the answer but I was thinking of a simpler solution and you just answered it.

Thanks!

TDturbo *theoretically* you're right. What matters is not the pressure of the intake air, but the number of oxygen molecules in the intake air charge. As I'm sure you're aware, there isn't really that much oxygen in air (21%) theoretically, if you could supplement the oxygen content of the air flowing into the engine (say to 42%) and you had the ability to supply the correct amount of gasoline for the amount of oxygen molecules, you could operate at an altitude where the air density is half that of sea level (approximately 22,000') and still make sea level power.

As a practical matter, no. Even if you had some method of regulating fuel flow to match the amount of oxygen present in the cylinders, you just wouldn't be able to carry enough oxygen to make a diffference. Your 540 running unthrottled at 2400 rpm will have about 375 cubic feet of air running through it each minute. To supply even a small percentage of that flow would require a huge cylinder of oxygen. (as Corona pointed out a scuba tank holds 80 cubic feet)

If you were using a scuba sized tank to double the oxygen content of the intake air, it would last about a minute.

 

[PropsForward]

Warning! Pure oxygen and petroleum products (oil, fuel, grease, etc) don't mix. If the O2 hits the smallest bit of oil the wrong way, then you could become a greasy spot!
This is why that automotive folks use nitrous-oxide. You get the same results your are seeking with a safer gas around an oil covered engine.


If you do decide to add NO2, you need to add more fuel as well, and lots of it! Going "full rich" will not be sufficient - or you would have to severely restrict the amount of NO2 you provide to balance out with the amount of fuel available at full rich.

This whole topic screams of getting some high altitude training. It same concepts that affect your physiology is affecting the engine. This is why turbo charged airplanes don't necessarily go faster, but rather they can go higher.

Regards,