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Old 01-04-2008, 10:41 PM   #1
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On all the cars I've had I def. felt the inscrease in power in the winter compared to summer.

To me the most obvious thing is the throttle response. Almost seems like my car has individual throttle bodies when it's super cold and it seems like there's a dead rat in my intake when it's hot outside.
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Old 01-05-2008, 06:31 AM   #2
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I don't know if you feel it in normally aspirated cars, but any forced induction (i.e. turbocharged) motors, it makes a big difference; hence the intercoolers. Porsche learned this long ago on the 962 program where they went with water to air intercoolers to reduce intake temperatures.
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Old 01-05-2008, 07:03 AM   #3
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What is the reason non forced induction cars do not have intercoolers?
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Old 01-05-2008, 07:14 AM   #4
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Gary-

Good question I've never really considered, but I'd have to guess some of the reasons are:

cost added to engine package
added complexity to engine
lack of effeciency in NA motors vs. forced induction

I'm thinking about the induction temperature differences between a NA car @ 20F-110F max range vs. the turbo car working with exhaust which could be several hundred degrees F.

maybe other reasons too.
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Old 01-05-2008, 07:22 AM   #5
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Gary,

My guess is the temperature of the compressed air (whether turbocharged or supercharged) is hotter than normal. Maybe an intercooler lowers the temperature to a level equal to the air charge of a non-FI engine.

Your question is intersting. Is there a way to efficiently cool the temperature of air on a normally aspirated engine? Other than the traditional cool air intake systems that are so popular maybe there isn't anymore benefit from intercoolers, etc.

Just a guess.

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Old 01-05-2008, 08:53 AM   #6
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when i get my best 0-60 times its about 45 -50 degrees, so i think it can make a big diffrence.
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Old 01-05-2008, 04:35 PM   #7
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Quote:
Originally Posted by blkboxster
when i get my best 0-60 times its about 45 -50 degrees, so i think it can make a big diffrence.
It would continue to get better with lower temps but your tires grip starts to suffer as temps drop and traction suffers.
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Old 01-05-2008, 06:19 PM   #8
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"There's a few really good points made here. Forgive me if I go on a little, but I assure you that none of the following was copied from some other web site .

To start with, as everyone has said, horsepower, or more directly, torque increases with air density. To put is simply, the more mass of air you can get into a cylinder the more force the combustion process will have on that cylinder when it's lit. Typical fluids, air included, get less dense with higher temperature, meaning there is less mass of a given volume as the temperature of the fluid increases. The fuel metering system in the car can sense the increase or decrease in air temperature and volume and adjust fuel flow accordingly, allowing for the proper mixture for good combustion.

Topless, it's true that a turbine engine, such as a jet on an airplane can also make more power under cooler air conditions, but power isn't the reason for the longer runway needed for take-off. That's due to the differences in ar density providing differences in lift. Hotter air, being less dense, provides less lift so the plane needs to be going faster before the lift force is sufficient to raise the plane.

Gary in BR, an intercooler uses outside air to cool the intake charge of a turbocharged engine. The charge has been heated by the act of compressing the air. It is then passed a radiator that exchanges heat with air from the outside of the car to bring the charge temp closer to atmospheric. In a normally aspirated engine, there is no compression of the intake charge so air temp doesn't raise anywhere close to that of a turbocharged car Running the intake air through a radiator that can't lower temps below atmospheric anyway would serve little purpose. Intercooling is a huge airflow restriction that can only be justified if the effects of the pressure drop are offset by the effects of providing a cooler intake charge."

Could it be?

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