Temperature vs. Horsepower
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Temperature vs. Horsepower We had a dyno day this past weekend and I heard something interesting and wanted to see what everyone thought. I was told that for every degree of temp drop that you can expect 1-1.25 additional hp for N/A applications and 1.25-1.5 additional hp for F/I. How true is this? So my car put down 390rwhp in 96 degree weather which would mean that it would be putting down 420rwhp in 65 degree weather. Is this possible?
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I've used the Engine Tuner's Calculator found on this website: http://wahiduddin.net/calc/calc_hp_dp.htm.
You can play around with temp, humidity, altitude etc..
General rule of thumb is a ~1% change in HP per every 10 degrees.
PHX is 1290 feet..I'm coming up with a 3.2% change, using your 96f, and 65f temp (assuming humidity, pressure the same).
There are some interesting articles on that website. Thats my understanding of the process. Hope that helps..WeathermanShawn..
You can play around with temp, humidity, altitude etc..
General rule of thumb is a ~1% change in HP per every 10 degrees.
PHX is 1290 feet..I'm coming up with a 3.2% change, using your 96f, and 65f temp (assuming humidity, pressure the same).
There are some interesting articles on that website. Thats my understanding of the process. Hope that helps..WeathermanShawn..
For uncorrected numbers yes....but for corrected SAE numbers theoretically the difference should be zero. Of course the coorection isn't perfect so you will see some small changes but don't expect much....
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From: Was New Orleans, but swam to Baton Rouge
Originally Posted by cantdrv65
For uncorrected numbers yes....but for corrected SAE numbers theoretically the difference should be zero. Of course the coorection isn't perfect so you will see some small changes but don't expect much....
unless of course youre pinging in the hot weather, in which case youll have better results when its cooler and your motor is not pulling timing. Aside from that the correction factor is pretty good at what it does.
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From: Sunny London, UK
The ECM will also pull timing even if its not pinging when IAT temp hits certain values usually over around ~28*C (Dont ask me what that is in ancient legacy *F) 
Mainly because if spark isnt reduced it will ping due to hotter charge temps.
Thats why a 160* thermo is good as it helps keep heads etc cooler to reduce charge temp transfer.
Mainly because if spark isnt reduced it will ping due to hotter charge temps.
Thats why a 160* thermo is good as it helps keep heads etc cooler to reduce charge temp transfer.
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Originally Posted by cantdrv65
For uncorrected numbers yes....but for corrected SAE numbers theoretically the difference should be zero. Of course the coorection isn't perfect so you will see some small changes but don't expect much....
CF (correction factor) is just that. A computed factor/equation. It's not perfect, and cant really account for how much a certain motor may enjoy the added oxygen.
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