nah dude you came in here saying that shit like it's fact. if you think about it, for only a second, you would realize that the argument is nothing but horse shit. does your car run stronger on cool days vs hot summer days? well according to your post it wouldn't matter, because the turbo heats it up to the same temp no matter what. Wrong!
[quote author=Steve0 link=topic=138252.msg2989418#msg2989418 date=1236832272]
If you wanna play with "n" variable, then you have the 2nd "argument" I gave. Hot air is less dense, and thus you are pulling in less oxygen, you're obviously going to make less power. I also said I was no chemist and was not sure the validity of the answer.
[1] How much less dense is 90 degree air than 80 degree air? [2] How much less power are you gonna make? [3] Enough to matter? I have no idea.
I also stand by my claims that part of the gain on many cars from intake systems is from the volume of air being ingested. There are many high horsepower turbo cars out there with an open element right next to the motor.
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to answer your questions, you first have to take into account absolute pressure and humidity. both of those will affect air density. if you were to assume 29.92 inches of mercury and 50% relative humidity,
[1] the density of 90° air would be 1.145 kg/m^3 and 80° air would be 1.17kg/m^3, a 2.14% change. lets assume mazda strapped the MZR DISI to an engine dyno, and dynoed the car using the standard reference conditions (22.235"hg, 0% RH, and 77°F)(as per SAE J1349) and came up with 263 peak horsepower. if the temp in the air went up to 90° leaving other variables unchanged,
[2] you can expect a drop of almost 4 horsepower. but also consider your pressure and humidity... those have an impact as well. So does it matter?
[3] I would say yes. Dread would say no. who's to say either of us are right? make up your own mind on that one. I prefer the best solution, some prefer the easiest solution. cp-e now caters to both types
and of course, a lot of the gain in power comes from REMOVING THE RESTRICTIONS. anytime you reduce the amount of power needed to move air through the cylinders (pumping losses), you will have more power available to spin the tires. the same theory applies to the exhaust side of the motor. this is probably the bulk of the HP gain, but definitely not the only variable in the equation of making power.