2005-2014 Mustangs Discussions on the latest S197 model Mustangs from Ford.

HP gain with cooler weather?

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Old Nov 13, 2012 | 12:38 PM
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kevinmalec
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Question HP gain with cooler weather?

I noticed since the weather has dropped significantly in the mornings, the Mustang feels a lot quicker and is pulling a lot harder as well. During the hot summer season here in GA, my car sometimes ran like dog....

What is the general rule of thumb when it comes to HP gain with cooler weather?

Is it like a 1% gain in hp for every 10 degrees cooler it is?
Old Nov 13, 2012 | 01:49 PM
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Yep. Not sure if they change seasonal gas formulas in GA, but that would also have an effect.

High Humidity levels really mess with these cars too.

Another old rule of thumb is dropping 100 pounds is equivalent to gaining 10hp
Old Nov 13, 2012 | 02:00 PM
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Originally Posted by jpplaw
Yep. Not sure if they change seasonal gas formulas in GA, but that would also have an effect.

High Humidity levels really mess with these cars too.

Another old rule of thumb is dropping 100 pounds is equivalent to gaining 10hp
Thanks for chiming in! I am not sure if they change gas formulas here in GA either. However, I do notice on hot humid days, I feel like I am down to 3 cylinders. LOL
Old Nov 13, 2012 | 02:09 PM
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I cant say what are the hp gain but lemme tell you i usually read 8 lbs on boost gauge but with this cold temp it alway boosting at 10lbs, if this car could push same in hot weather this would be awrsome
Old Nov 13, 2012 | 02:16 PM
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Well Kevin, I'd have to suspect so. Research 'work' in a thermodynamics book and you'll see that efficiency is directly related to system temperature and environment temperature. Or if you look at a heat transfer book, hot components in cooler atmospheres (relatively speaking) transfer heat to the surrounding environment (called a 'heat sink') a little quicker due to the increased temperature gradient of a hot car and a cold environment, compared to a hot car and 80 degree temps. Humidity also plays a huge role in this as humidity retards the rate of heat transfer between two bodies and thus negatively effects engine efficiency. Sorry for the lesson, I just loved thermodynamics class and am happy that I finally stumbled upon a real world application on accident haha.

As for the gasoline blend, however, I don't have a clue. That's chemical engineering and I'm for the most part in the dark there haha.
Old Nov 13, 2012 | 02:35 PM
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Originally Posted by MadStang40
Well Kevin, I'd have to suspect so. Research 'work' in a thermodynamics book and you'll see that efficiency is directly related to system temperature and environment temperature. Or if you look at a heat transfer book, hot components in cooler atmospheres (relatively speaking) transfer heat to the surrounding environment (called a 'heat sink') a little quicker due to the increased temperature gradient of a hot car and a cold environment, compared to a hot car and 80 degree temps. Humidity also plays a huge role in this as humidity retards the rate of heat transfer between two bodies and thus negatively effects engine efficiency. Sorry for the lesson, I just loved thermodynamics class and am happy that I finally stumbled upon a real world application on accident haha.

As for the gasoline blend, however, I don't have a clue. That's chemical engineering and I'm for the most part in the dark there haha.
Impressive. Thanks for the scientific educational point of view! ;-)

Last edited by kevinmalec; Nov 13, 2012 at 02:37 PM.
Old Nov 13, 2012 | 02:40 PM
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Originally Posted by mighted1987
I cant say what are the hp gain but lemme tell you i usually read 8 lbs on boost gauge but with this cold temp it alway boosting at 10lbs, if this car could push same in hot weather this would be awrsome
Nice! Giddy up!
Old Nov 13, 2012 | 02:41 PM
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Cooler air = Denser air! More air, more fuel to compensate, more power! It's the same reason why people run intercoolers or have ice packs sitting on their intake before 1/4 mile runs .
Old Nov 13, 2012 | 02:45 PM
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Originally Posted by siggyfreud
Cooler air = Denser air! More air, more fuel to compensate, more power! It's the same reason why people run intercoolers or have ice packs sitting on their intake before 1/4 mile runs .
True...colder air contracts so there are more oxygen molecules per cubic foot of air...so the more O2... the more fuel can be added...
Old Nov 13, 2012 | 03:02 PM
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Originally Posted by siggyfreud
Cooler air = Denser air! More air, more fuel to compensate, more power! It's the same reason why people run intercoolers or have ice packs sitting on their intake before 1/4 mile runs .
Besides cooler air being denser, your ecm will pull some timing with a hotter air intake temp. Timing = power. I don't think colder air will affect the amount of fuel being delivered at WOT, you'll probably run a little leaner, but it will at part throttle, that's why you generally get worse mpg in the winter.

Last edited by moosestang; Nov 13, 2012 at 03:31 PM.



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