I was just doing a little googling and thinking because of this super cold weather we have right now in upstate New York, its 0 degree's F

So according to yahoo answers the difference between running a car in 30 (86) C to 0 (32) C is as much as a 10% Hp gain? Considering its 0 degrees F here that would mean its more like 15% for my location in this temp.

So does this really mean I would an extra 30 hp (If I had 200 hp) more then if I was driving in 86 F degree weather like Hawaii which is where I used to live and drive my R56.

In closing, I'm about to get an RMW tune, would it be actually possible to Tune for extreme cold weather driving?

 

Air density is the issue. Cold air is denser than warm air so when the engine is sucking in air, what it gets at 0° is more OX than at say 85°. Lots of guys increase the power output by substituting a cold air intake to their superchargers (but those things, sadly, are a thing of the past). Cold, dense air influences other things as well. Golf ***** don't fly as far in cold weather. Airplanes lift off the ground in a much shorter distance, greater lift.

 

So considering it is a turbocharged car, is what I said above correct as far as HP gains?

 

The cars are pretty good and adjust for air density. They have Mass Air Flow, Air intake, and Manifold Absolute Pressure Senors. With all the information they pull the car will actually pull less boost because of the denser air. Without having a proper tuner, you won't really see a big difference unlike a NA motor that would vary quite a bit. Plus i'ts not condisdered a good idea to tune for weather considering it can change and change quickly. Plus as the engine gets warm your IAT will rise with it.

 

Griswald is correct. The car makes adjustments to achieve certain power target values. They do this for consistency in the driving experience.

For example in cold weather you might make 10 psi boost to hit target values where as in the summer you might be boosting to 16 psi.

 

Oh, for the good old days of Lucas electricals, triple SU carburetors and the balancing needles.

 

Of course that new found horsepower is now spent trying to push the car through the thicker, colder air.

There's no such thing as a free lunch... Especially in fluid dynamics!

 

Yahoo answers, the definitive automotive authority.

 

Changes in air density does (more or less) directly relate to power. So if you increase air density by 10% then power will also increase by 10%. But in today's microprocessor controlled engines this is usually not the case (as I stated above the car is trying to hit certain power targets so it varies boost to accomplish that) but for example...let's say you are tuned to always boost to 18 psi then yes it would be true (more or less).

 

Then why are we buying big intercoolers to cool the intake charge better than the factory unit?

 

I really don't know, same power with less boost which equates to less wear and tear. The larger intercoolers will decrease temperatures in the 10-15F range compared to stock. Not a huge difference. Also less susceptible to heat soak.

Now with a tune you might be able to get something from them but then I think meth injection is the better route due to the octane boost.

For those that are doing the density calculation, don't forget to convert to absolute temperatures (Rankine or Kelvin).

 

So after I get a RMW tune the cold would make a difference then?

 

You need to ask them. For consistent drivability, some factor that it in. With the JB+ piggyback tune you could turn up the dial in cold weather.

 

With the colder air/bigger but not too big intercooler you will/may gain alittle HP don't think it will be 10% unless it was a poor managed ECU/engine to start with. What it will do is help you to maintain that/your HP for a longer period of time due to less Heat Soak..

 

We buy Large intercoolers to prevent heat soak and power loss. They do not add power to the system.

 

Someone who hasn't posted in quite a while had this quote on his signature:
"If you can't go fast with 90 HP, 900 won't help you."
Not quite sure how that equates to the weight to power ratio but there is an obscure sense of logic to it.

 

Big intercoolers flow better as well (potentially adding power by removing bottlenecks and obstruction, but not much on an otherwise stock engine until you're pushing more air in).

The real reason for the intercooler is as-stated, to prevent heat soak and keep the power near stock levels when things get hot.

 

Usually the bigger intercoolers introduce a pressure drop into the system which is indicative of flow restriction.

The inlet and outlet are the same size.

The helix version has about a 0.5 psi drop.

 

Fly'n Brick's quote about 90 & 900 makes sense in so many ways...usually (in Michigan at least) cold weather equals lousy driving conditions. It's close to 0 degree F today, but the roads are covered with snow and ice. Everybody's either goin' slow or in a ditch today.

 

I should have mentioned I was relating intercooler experiences from other cars (Saab, Volvo) in which intercooler upgrades typically expand inlet/outlet 1-2" in diameter and have better-flowing cores.

I haven't even looked at Mini intercooler options, so I defer