Winter boost boost...

You are getting cooler denser air which means the turbo isn't working as hard as it would when it's warm and humid. So as you get warmer air...you technically lose a little performance. So it's not just your butt dyno...it's real.

Quote from Br4hm4

You are getting cooler denser air which means the turbo isn't working as hard as it would when it's warm and humid. So as you get warmer air...you technically lose a little performance. So it's not just your butt dyno...it's real.

It's a science thing, ideal gas law PV = nRT, where pressure (P) times volume (V) equals the actual number of gas molecules (n) times the gas constant (R) times the temperature (T). PV = nRT. If the Pressure and Volume side of the equation stays relatively the same and the temperature goes down then the number of gas molecules MUST go up so you end up with more oxygen to improve combustion.

Loving the nerds on the forum!

Quote from Doc&Ruby

Correct, ideal gas law is simple, but it's application to engineering processes is rarely so.

I realize that cold conditions MUST increase efficiency in a turbo/intercooler setup, my question is more about 'how much?'

I suspect Few of us could detect ssy a 5hp change, my question is has anyone else noticed this.

Also want to hear from our vendors who have experience with many setups vs my own experience with just one.

Yeap, as the outside air temp gets colder, the engine produces more power because of the reasons dewman mentioned. The ECM uses the IAT (intake air temp) sensor to add extra fuel to make up for the higher mass of air entering the engine. Also, the spark timing has modifications based on IAT also that will increase spark timing with lower IAT's. As for how much power is gained, the only way I could think to do that would be to run the same setup on a dyno, with no temperature correction on a really hot day and a cold night. That should get close to figuring it out between those 2 temps. Also, theoretically you could also use the calculated increase in mass to determine the increase in power also, since air mass to horsepower is a relatively easy calculation.

Nerds make the best music...

Quote from dewman

It's a science thing, ideal gas law PV = nRT, where pressure (P) times volume (V) equals the actual number of gas molecules (n) times the gas constant (R) times the temperature (T). PV = nRT. If the Pressure and Volume side of the equation stays relatively the same and the temperature goes down then the number of gas molecules MUST go up so you end up with more oxygen to improve combustion.

Just yesterday I was reading the effects of nonstandard pressure and temperature vs. indicated altimeter readings. It was easy the immediate effect was a headache! Hah

Everything Dave said is correct. If there is anyone reading this thread that found any of it a little confusing, Here’s the simple version:

8psi at 40* is going to make more power than 8psi at 80* because the colder air is more dense and therefore has more oxygen molecules per cubic inch (or whatever volume unit you choose).

This effect is felt even in naturally aspirated cars, and is why the fall/winter months are when we generally see a lot of 1/4 mile records get broken.

Doing an A B test would be cool. Sadly MI doesn't get many warm days and cold nights in the same day. It's generally either hot and muggy or baron arctic wasteland with a couple months of 40s and 50s between each one.

Quote from Kyle D

Everything Dave said is correct. If there is anyone reading this thread that found any of it a little confusing, Here’s the simple version:

8psi at 40* is going to make more power than 8psi at 80* because the colder air is more dense and therefore has more oxygen molecules per cubic inch (or whatever volume unit you choose).

This effect is felt even in naturally aspirated cars, and is why the fall/winter months are when we generally see a lot of 1/4 mile records get broken.

Doing an A B test would be cool. Sadly MI doesn't get many warm days and cold nights in the same day. It's generally either hot and muggy or baron arctic wasteland with a couple months of 40s and 50s between each one.

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...,.was hoping someone broke it down lol

Cold weather, more power, grunt, grunt grunt.

That should sum it up.

Quote from dewman

Cold weather, more power, grunt, grunt grunt.

That should sum it up.

So does this mean my supercharger is going to feel really slow come spring! 🙃