IAT and boosted horsepower?
IAT and boosted horsepower? if your intake air temp was guranteed to be 35 degrees or cooler (even if boost was increased 25%), compared to 110 degrees at the super or turbochargers discharge, how much more HP could you gain (with a tune)? How much HP gain is possible in a N/A application?
You want your IAT's to be accurate to ensure correct fueling. Tricking the PCM can lead to issues like detonation. Typically, horsepower losses are prevented with cooler IAT sensor readings because the IAT will start to pull timing at 100+ degree temps. Aside from the IAT, cooler charge temps produce more power because the air density is increased. More air plus more fuel equals more power generally speaking. That's why cooler boost (intercooled setups) makes more power. The more efficient the intercooler, the more power can be had. A good example might be to look at the difference between the intercooled and non-intercooled Magnachargers for your truck. I think the power differences are only in the 10~20hp range if I remember correctly. I know in my car (N/A stock internals Z28), I can see up to a 0.1 second difference in my ET for every 10 degrees difference in the weather. That's based on the fact that I turned a 12.5@109 (1.71 60') on a 60-degree day and a 12.9@107 (1.85 60') on a high 80-degree day.
I wasnt talking about tricking the IAT heh heh. 
I understand that cooler, more dense air makes more HP, im just curious as to how much. I know even my truck had a noticeable amount more ***** in 40 degree weather than it did in 80 degrees. the GTO was even more of a difference, due to the way the intake and engine bay is from the factory.
thats the info I was looking for on the 1/4 times. so is there a rule of thumb, like every 10 degrees cooler will get you X more HP? generally speaking of course...
I understand that cooler, more dense air makes more HP, im just curious as to how much. I know even my truck had a noticeable amount more ***** in 40 degree weather than it did in 80 degrees. the GTO was even more of a difference, due to the way the intake and engine bay is from the factory.thats the info I was looking for on the 1/4 times. so is there a rule of thumb, like every 10 degrees cooler will get you X more HP? generally speaking of course...
If I were to guess, I'd say it's somewhere close to being a ~2% increase/decrease in power for every 10*F change in temperature. But, that's me guessing...
**I say percentage too becuase I don't believe a smaller motor will see the same 10hp:10*F ratio that I have seen in my LS1.
**I say percentage too becuase I don't believe a smaller motor will see the same 10hp:10*F ratio that I have seen in my LS1.
Last edited by SSpdDmon; Sep 6, 2006 at 07:17 PM.
Mine is a non intercooled Vortech making about 5 PSI.
I dynoed it without and then with water/alcohol injection.
The IAT dropped by about 100F and gained 30 RWHP (380 to 410).
It's only physics: pV=nRT
Cooling the charge air you have more air in the same volume and proportionally more power. I calculated the theoretical gain and it matches the dyno numbers
I dynoed it without and then with water/alcohol injection.
The IAT dropped by about 100F and gained 30 RWHP (380 to 410).
It's only physics: pV=nRT
Cooling the charge air you have more air in the same volume and proportionally more power. I calculated the theoretical gain and it matches the dyno numbers
Teching In
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Using the first comparison, the air density gain from 110 degrees to 35 degrees is 15%. Don't forget that the vehicle will also be pushing it's way through the higher density air thereby consuming more power due to aerodynamic drag losses.
