This is exactly where my numbers came from in a previous post. I do my tuning on a daily basis. That is how we can compare apples to apples across many engines varying in spec to spec.

 

Good info here.
http://www.proficientperformance.com...conditions.htm

 

I live in Colorado.. Single digit humidity is the rule here. I can tell you as a fact that humidity makes power.. By that.. I mean.. 30-40 percent humidity as compared to 4-5 percent.. I run a Big block 454 LS4 with 10.25:1 compression and high flow heads with stock exhaust manifold. Cool air coupled with some double digit humidity makes power.. A lot of power !! I am not sure of all the dynamics involved as my statement is anecdotal. Seat of the pants.. And I mean it.. Seat of the pants ! I feel it.. It has scared me on occasion. My postulate is this.. Humidity in the right amount can make more power for 2 reasons.. Hydrogen and Oxygen. IF you have a high enough temperature and just the right amount of water vapor, it can be split into its single components of Hydrogen and Oxygen. Both are very explosive components. Key is... Splitting them. Too much water vapor, it will not split and hurts power, a smaller amount can be split and pow baby pow !! So.. MY conclusion is.. Does Humidity or water vapor make more power ? My conclusion is.. It can.. But it depends..

 

wow. 10 year bump. interesting read

 

My previous built subaru with 100% meth injection off a m95 nozzle maxxed out on flow would drop my intake temps to 65-75* down from 110-150* depending on how much heat soak I had in the intercooler. Meth drops IAT's like crazy.

So with temp no longer a factor, during a 90-100% humidity night with my subaru and another c6z06. Our times were crap. The subie couldn't break 13.0 with 1.7 60ft and the vette right beside me at 12.8-13.0. My subaru normally ran 12.5 with 1.6 60ft and the c6z06 does an easy 12.0 -12.2 with normal conditions.

Your theory is flawed


Just realized how old this was...

 

my mommas camry goes stronger with higher humidity.yes humidity=good.

 

1st - Champion Necro Post


2nd - Humidity displaces oxygen per cubic foot of air, replacing it with water vapor. Water is not high octane or infinite octane.

That is baloney.

All factors need weighed in to see what effective DA is for a given combo and then you can see that it doesnt "add" power it just doesnt hurt it. Its the cold air that made the power not humidity.

http://www.small-block-chevy.com/WE.htm

I tune cars in the PNW where I can have 30% humidity in the morning with ambient temps of 57-67* and then that afternoon have rain and relative humidity of 85% and the same temps. Guess what is better weather to dyno in.

 

For Power reasons, you are only at the altitude known when humidity is 50 percent. For example, if you are at 5000 feet and humidity is only 5 percent, you are equated at 9000 feet for hp reasons because of the lack of humidity. If Humidity is 50 percent, then for hp reasons, you are at 5000 feet. Remember this, you lose around 4 percent of hp for every 1000 feet. Those of us that live at high altitude and also pilots know this. Once humidity gets over 50 percent, it could be that the water molecules begins to displace the air and then you start to lose power. I suspect this is the case, but have not studied it since this rarely happens in Colorado where I live..

 

I dyno'd a car yesterday that was originally dyno'd at 26% Humidity and made 468whp. Yesterday at 80% it made 436whp. Your DA calculator needs fine tuned I think. 5000 ft and 5% is a DA of 6300 ft at 60*F, and the current altimeter reading for Denver International of 29.85". Its 6934 ft if it was at 70*F with the same conditions.

Using the Wallace calculator with those numbers, the sea level power correction is 1.247 for 5% and 1.266 for 50%. On a car that makes 1000whp at sea level this would mean it would be dynoing at 802whp and at 1.266 the same motor would be 789.8whp. In theory thats a rough estimate, In practice I saw far greater losses at sea level.

That means it lost 1.9% power in 45% humidity, it went from 81.5% air density to 80.4% meaning a loss of 1% oxygen. Bump it to 80% and we are at 1.279 correction, so 3.2% lost at the same ambient temp conditions. This would bring that 1000whp motor down to 781whp. Again refer to real world results at only 470whp and you can see that humidity plays a far greater role.

 

Thank you, can you post logs from both runs?

 

I can look for the logs from the other day but the 26% humidity run was awhile ago and I am not sure I saved them.