The effects of altitude on your RX-1

[spray25]

I ran across this Horse Poser calculator and thought you might all find it interesting.

http://www.mtv411.com/auto/Stroke-Bore- ... #BasAltCal

Current Elevation is the elevation at which you know the HP. So that is 0.

Current HP is known HP at that elevation. So 140 to 145 should work.

New elevation is the elevation you want to know the HP at. For me it is 5000-8000.

Pretty interesting how much you lose.


Here is another formula that is interesting. It calculates the loss of compression at see level. I have it in a spreadsheet. If anyone would like it I can email it.

Altitude plays an important role in determining compression ratios. If the altitude in the area where the vehicle is driven is significantly higher than sea level, then the compression ratios will vary. To determine the effects of the altitude on a calculated compression ratio, us the following formula: Corrected Compression Ratio = CR - (altitude / 1000) x 0.2

using this formula the RX-1's compression ratio goes from 11.8 at sea level to 10.8 at 5000 ft and 10.2 at 8000.

So are we all shaving our heads now?

 

[1xr]

Is'nt it 3% loss for every 1000 feet.

 

[spray25]

That's pretty darned close.

The calculator says at 5000 feet it's a 17.24% drop or 3.45% per thousand feet.

At 8000 feet it is a 26.2% loss or 3.27% per thousand feet.

 

[LazyBastard]

Thats interesting about the "corrected compression ratio"....

That means that the absolute pressure obtained during compression is related on a 11.8:10.8 ratio when going from 0 to 5000 feet.

(For those who are not so swift.... this does not mean that the compression changes, that can only be done by modifying the combustion chamber or piston. It just means change in absolute pressure obtained).