As a Huey slick pilot in Viet Nam all of 1969 I was often in situations where I was in marginal control of the number of persons getting into my aircraft and certainly did not have the option of waiting for a better density altitude to time my takeoffs...No one has a more visceral appreciation of Density Altitude than I ....

That cold air is more dense than hot was never the question.

"Therefore, the existing fuel charge burns
slightly more completely, resulting in more power!!!!!!! No additional fuel is
necessary as it was already there but just not being burnt as efficently." --Ridge

I find this a very interesting statement and assumption.... if it is true for some specific engine with which you are dealing I suggest it means that the sensors feeding the fuel injection circuit are not set at proper settings...

It would suggest that not enough oxygen is in that particular cylinder compared to the amount of fuel being injected...

I certainly agree that the word 'slightly' is appropriate in that case and is the reason I asked if anyone had done the math on these circumstances.....

If you put substantially more air into the chamber (as with the 18% lower figure mentioned earlier) I do not think it would be a measureable increase in power without the addition of fuel to keep the fuel/air ratio at near proper relationships...

If we go with the example of the air getting hotter due to the compression of the turbo fan... and needing cooling in order to place more air into the cylinder... then placing more air into the cylinder and heating it BY compressing it... brings to question how the temps inside the combustion chamber wind up being cooler rather than hotter... The working temps of the turbo diesel necessitated the addition of the oil squirters for the bottom of the pistons when that increase in air volume happened....why would additional air at the start of the compression stroke due to cooling of the air not produce the same effect... higher combustion chamber working temps ?

I just thought that after the performance figures were mentioned ( not that you claimed them for your unit or car ),, that an examination of the physics would be in order for all interested in Diesel engines...

Your construction implementation was truly beautiful... and is in NO way reduced by a review of the physics of the situation with regard to potential performance gains..... Greg