Why engine runs so good at night? - Toyota Nation Forum : Toyota Car and Truck Forums

JetspeedCamry · 03-09-2005, 04:37 PM

I've alwats wondered why my car runs so well at night.
Even if it's a cool/cold day..the night is always better...
What is it about night time that creates the better performance...coz it's not just temprature.
Was thinking air-density or something.

CamryPunk · 03-09-2005, 04:41 PM

^ Colder air means more dense air. Meaning more molecules for your car to ignite which makes it a bit more peppy.

Mike Gerber · 03-09-2005, 06:19 PM

CamryPunk is correct. Colder air is more dense. As a gas (or in this case, gas and air mixture) is cooled, it actually shrinks a little. This allows your cylinders to be filled with a slightly larger volume of gas and air. This is why you generally have more power in cooler temperatures. Back in my day (I won't tell you how long ago) drag racers would pack their fuel pumps with bags of ice between races to help lower the temperature of the fuel going through the fuel pump. Remember, these were external, mechanical fuel pumps back then.

Mike

whocares04 · 03-09-2005, 07:48 PM

sooo....mike....we should go buy a 99cent bag-o-ice and dump it in our gas tanks?!?!

p@nda · 03-09-2005, 07:56 PM

Quote:

Originally Posted by whocares04

sooo....mike....we should go buy a 99cent bag-o-ice and dump it in our gas tanks?!?!

hopefully you don't mean dumping the ice in the fuel tank.....but setting it on top....on the outside

whocares04 · 03-09-2005, 07:59 PM

^^^yea that was BIG sarcasm......i meant "dry ice" cuz it's alot colder

Toysrme · 03-09-2005, 08:25 PM

^^^
Drag racers still pack ice around their carburetor & intercoolers with ice, water injection & intercooler water spray use ice water.
Some people are using compressed air, co2, or nitrogen onto their intercooler piping to freeze it.

The ford lightning from the last few years using a small (underpowered) A/C unit to cool it's charge air.

dna59 · 03-09-2005, 09:12 PM

I used to experience this when i would be on the highway coming from my girls house at like 1 in the morn. Where she lives get's really cool at night and I could really feel the difference.

whocares04 · 03-09-2005, 09:34 PM

about that toysrme...the STi's have an IC spray from the factory...has any of u w/turbos added any kind of spray....like modified washer nozzles on the sides (if u have an IC)

Neon · 03-09-2005, 09:42 PM

Quote:

Originally Posted by whocares04

about that toysrme...the STi's have an IC spray from the factory...has any of u w/turbos added any kind of spray....like modified washer nozzles on the sides (if u have an IC)

Tony The Tiger !!!!!!!!!!!!

bowlofturtle · 03-09-2005, 11:37 PM

at our school we proved it right. we had a turbo mustang. We put a bag of ice somewhere near the intercooler not to sure where. ran it on the dyno. proven to be 20-30HP more. with that alone.

Toysrme · 03-10-2005, 12:03 AM

The thing about intercooler water sprays is that they're not effective in say 75 or 80% of boosted driving. The intercooler itself can soak up a large amount of heat.

If it has a nice bit of mass to it and can store a lot of heat energy, there really isn't much of a reason to run an intercooler spray in something like a drag race. Washer nozzels don't work well *at all*. You need a very fine mist, and full coverage.

Now if you're racing a setup on a track, or on the highway for more than around 15-20 seconds at a time, the intercooler is going to heat soak.

People have the wrong general idea about how intercoolers work. The metal absorbs the heat of the hot air. The vast majority of the time, the itnercooler itself isn't even noticably warmer. When you DO happen to heat the intercooler close to the air temperature, the Airflow around the intercooler has a tough time cooling it back off quickly (the capacity to cooler the intercooler is much slower than the intercooler absorbing the heat fro the air).

To divulge a great secrit, the agricultural industry has the most ass kicking atomizers. Very, very small particles can be achived that are perfect for spraying on coolers, and spraying into the engine for water injection.

SnakeyeS · 03-10-2005, 08:15 AM

My IC Engines professor was saying that driving in the winter(cold weather) alone doesn't give you that much of a power increase because the power gained by higher density air is lost in increased internal engine friction. It didnt' make complete sense to me, but he's been doing this for 35 yrs and has a PHD. What do I know?

CamryPunk · 03-10-2005, 10:13 AM

They do have that nitrous sprayer as well that cools down the intercooler.

ohnoyuji · 03-10-2005, 09:59 PM

I don't agree that Colder it gets the denser it is notion.
Colder doesn't mean denser dude.

Colder will only mean that the air molecule moves at a slower rate than the normal or higher temperature.
Then why colder air is better to engine? GUess what?
Colder air have lower temperature of ignition. This is from the very very basic Thermodynamic course in Mechanical Engineering. Especially for a 4 stroke car engine, the stroke will gets better if the induction air gets colder.

Here's the picture of the 4 stroke engine cycle. From this equation
Standard Gas equation PV = nRT , If T is lower, P has to be higher if V stay constant. thus Pressure need for the compression stroke is smaller, thus runs smooher